微细磨削文献译文
平面磨床中英文外文翻译文献
平面磨床中英文外文翻译文献(文档含英文原文和中文翻译)Surface grindingSurface grinding is used to produce a smooth finish on flat surfaces. It is a widelyused abrasive machining process in which a spinning wheel covered in rough particles (grinding wheel) cuts chips of metallic or non metallic substance from a workpiece, making a face of it flat or smooth.ProcessSurface grinding is the most common of the grinding operations. It is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or nonmetallic materials to give them a more refined look or to attain a desired surface for a functional purpose.The surface grinder is composed of an abrasive wheel, a workholding device known asa chuck, and a reciprocating table. The chuck holds the material in place while it is being worked on. It can do this one of two ways: metallic pieces are held in place by a magnetic chuck, while nonmetallic pieces are held in place by vacuum or mechanical means. Factors to consider in surface grinding are the material of the grinding wheel and the material of the piece being worked on.Typical workpiece materials include cast iron and minor steel. These two materials don't tend to clog the grinding wheel while being processed. Other materials are aluminum, stainless steel, brass and some plastics. When grinding at high temperatures, the material tends to become weakened and is more inclined to corrode. This can also result in a loss of magnetism in materials where this is applicable. The tolerances that are normally achieved with grinding are ± 2 × 10−4inches for a grinding a flat material, and ± 3 ×10−4 inches for a parallel surface.The grinding wheel is not limited to just a cylindrical shape, but can have a myriad of options that are useful in transferring different designs to the object being worked on. When surface grinding an object, one must keep in mind that the shape of the wheel will be transferred to the material of the object like a mirror image.Spark out is a term used when precision values are sought and literally means "until the sparks are out (no more)". It involves passing the workpiece under the wheel, without resetting the depth of cut, more than once and generally multiple times. This ensures that any inconsistencies in the machine or workpiece are eliminated.EquipmentSurface Grinder with electromagnetic chuck, inset shows a Manual magnetic chuckA surface grinder is a machine tool used to provide precision ground surfaces, either to a critical size or for the surface finish.The typical precision of a surface grinder depends on the type and usage, however +/- 0.002 mm (+/- 0.0001") should be achievable on most surface grinders.The machine consists of a table that traverses both longitudinally and across the face of the wheel. The longitudinal feed is usually powered by hydraulics, as may the cross feed, however any mixture of hand, electrical or hydraulic may be used depending on the ultimate usage of the machine (i.e.: production, workshop, cost). The grinding wheel rotates in the spindle head and is also adjustable for height, by any of the methods described previously. Modern surface grinders are semi-automated, depth of cut and spark-out may be preset as to the number of passes and once setup the machining process requires very little operator intervention.Depending on the workpiece material, the work is generally held by the use of a magnetic chuck. This may be either an electromagnetic chuck, or a manually operated, permanent magnet type chuck; both types are shown in the first image.The machine has provision for the application of coolant as well as the extraction of metal dust (metal and grinding particles).Types of surface grindersHorizontal-spindle (peripheral) surface grinders The periphery (flat edge) of the wheel is in contact with the workpiece, producing the flat surface. Peripheral grinding is used inhigh-precision work on simple flat surfaces; tapers or angled surfaces; slots; flat surfaces next to shoulders; recessed surfaces; and profiles.Vertical-spindle (wheel-face) grinders The face of a wheel (cup, cylinder, disc, or segmental wheel) is used on the flat surface. Wheel-face grinding is often used for fast material removal, but some machines can accomplish high-precision work. The workpiece is held on a reciprocating table, which can be varied according to the task, or arotary-table machine, with continuous or indexed rotation. Indexing allows loading or unloading one station while grinding operations are being performed on another.Disc grinders and double-disc grinders Disc grinding is similar to surface grinding, but with a larger contact area between disc and workpiece. Disc grinders are available in both vertical and horizontal spindle types. Double disc grinders work both sides of a workpiece simultaneously. Disc grinders are capable of achieving especially fine tolerances. Grinding wheels for surface grindersAluminum oxide, silicon carbide, diamond, and cubic boron nitride (CBN) are four commonly used abrasive materials for the surface of the grinding wheels. Of these materials, aluminum oxide is the most common. Because of cost, diamond and CBN grinding wheels are generally made with a core of less expensive material surrounded bya layer of diamond or CBN. Diamond and CBN wheels are very hard and are capable of economically grinding materials, such as ceramics and carbides, that cannot be ground by aluminum oxide or silicon carbide wheels.As with any grinding operation, the condition of the wheel is extremely important. Grinding dressers are used to maintain the condition of the wheel, these may be table mounted or mounted in the wheel head where they can be readily applied.LubricationLubricants are sometimes used to cool the workpiece and wheel, lubricate the interface, and remove swarf (chips). It must be applied directly to the cutting area to ensure that the fluid is not carried away by the grinding wheel. Common lubricants include water-soluble chemical fluids, water soluble oils, synthetic oils, and petroleum-based oils. The type of lubrication used depends on the workpiece material and is outlined in the table below.Types of lubricants used for grinding based on workpiece materialEffects on work material propertiesThe high temperatures encountered at the ground surface create residual stresses and a thin martensitic layer may form on the part surface; this decreases the fatigue strength. In ferromagnetic materials, if the temperature of the surface is raised beyond the Curie temperature then it may lose some magnetic properties. Finally, the surface may be more susceptible to corrosion.Trends of the Surface grinding machinesThe current trend is grinding shift shape, step, cut, fast jitter, three-dimensional curve surface grinding. It can be said, flat grinding mill is the largest class of machine tools in the evolution of the potential of a model.First, the development trend of surface grinding machine1. From the specification point of view, mainly with small grinding. The following table 200mm wide, almost 50%, small size and the mounting of the machine easier to transport; relatively small size machine tools, precision easy to do very high; in the international market upper, middle and small size of the potential demand for large flat grinding.2. From the control point of view, more than 70% for the NC type, there are uniaxial, biaxial and triaxial NC, up to five-axis control, especially of more than 400 large-size models, all for the NC type. Due to technological level of development lead to functional changes from the traditional flat grinding mill grinding to shape change, conventional control has been difficult to achieve functional requirements. CNC grinding has become amarket trend.3. From the functional point of view, more than 50% of the grinding process not only for the horizontal plane, and turned to shape, step, cut, fast jitter, three-dimensional curve surface grinding process, such as the ELB, BLM-based company to change grinding made of five-axis grinding center, enabling non-planar complex surface grinding; Unison, Trutech company's flexible grinding system can achieve forming, centerless, cylindrical, tool, contour grinding, etc.; there Yu Fu, Parker rapid jitter companies, such as grinding, grinding class reflects the grinding machine is the greatest potential in the evolution of a model.Second, the development shows four major changes1. High-speed, complex, high precision and high rigidity is still the main theme of the development of metal cutting machine tools, but there are new changes. Compound, from the original compound into the compound and the main consideration from the practical and efficient, such as cars, milling, turning, milling, drilling of the composite, the composite milling and EDM; from a functional point of view, for the compound machine highly considered for certain parts; from accuracy point of view, positioning accuracy <2μm, repeat accuracy ≤ ± 1μm the machine has been found everywhere; from the spindle speed point of view, 8.2kW spindle of 60000r/min, 13kW of 42000r / min, spindle speed is not the exclusive features of low power; from rigid point of view, there have been 60HRC hardness, machinability of materials processing center.2. Modular design has been applied in machine tool manufacturing had reached a pinnacle. Horizontal line, vertical line, the whole series, cross-Series modular design,whether it is Okuma, Makino, represented by Japan Machine Tool, or Haas, Cincinnati, represented by the U.S. machine tools, like point of view exactly the same shape, but the function is completely different modules posed by many is universal.3. The concept of automatic change. The traditional automatic machine is a pneumatic or hydraulic manipulator to achieve automatic workpiece, cutting, and now with the true meaning of multi-joint robot series to achieve the workpiece, the cutting, including the completion of parts stacking. Increase the scope of control of the group to enhance the flexibility of line, and auxiliary machinery greatly reduced.4. Increasing environmental requirements. In the exhibits, the vast majority of machine tool products are all-closed shell, absolutely no chips or cutting fluid splashing phenomenon. On the other hand, a large number of industrial cleaning machines and cutting fluid processor systems on display, modern manufacturing also reflects the growing demands of environmental protection.References1. Tool and Manufacturing Engineers Handbook (TMEH), 4th edition, Volume 1, Machining. Societyof Manufacturing Engineers, 19832. TMEH, Volume 1.3. Todd, Allen & Alting 1994, p. 141.4. Todd, Allen & Alting 1994, p. 139平面磨床维基百科平面磨床是用作在生产平面上加工工件的设备。
常用研磨机外文文献翻译、中英文翻译、外文翻译
常用研磨机外文文献翻译、中英文翻译、外文翻译Grinding machine is a crucial n processing method that offers high machining accuracy and can process a wide range of materials。
It is suitable for almost all kinds of material processing。
and can achieve very high n and shape accuracy。
even reaching the limit。
The machining accuracy of grinding device is simple and does not require complex ___.2.Types of Grinding MachinesGrinding machines are mainly used for n grinding of workpiece planes。
cylindrical workpiece surfaces (both inside and outside)。
tapered faces inside。
spheres。
thread faces。
and other types of ___ grinding machines。
including disc-type grinding machines。
shaft-type grinding machines。
ic grinding machines。
and special grinding machines.3.Disc-type Grinding MachineThe disc-type grinding machine is a type of grinding machine that uses a grinding disc to grind the ___。
机床加工外文文献翻译
机床加工外文文献翻译(含：英文原文及中文译文)文献出处：Shunmugam M. Basic Machining Operations and Cutting Technology[J]. Journal of the Institution of Engineers, 2014, 1(2):22-32. 英文原文Basic Machining Operations and Cutting TechnologyShunmugam MBasic Machining OperationsMachine was developed from the early Egyptian pedal car and John Wilkinson's trampoline. They provide rigid support for workpieces and tools and can precisely control their relative position and relative speed. Basically, metal cutting refers to a sharpened pry tool that removes a very narrow metal from the surface of a tough workpiece. Chips are discarded products. Compared with other workpieces, the chips are shorter, but there is a certain increase in the thickness of the uncut parts. The geometry of the workpiece surface depends on the shape of the tool and the path of the tool during machining operations.Most machining processes produce parts of different geometries. If a rough workpiece rotates on the central axis and the tool cuts into the workpiece surface parallel to the center of rotation, a rotating surface is created. This operation is called turning. If a hollow tube is machined onthe inner surface in the same way, this operation is called boring. When the diameter is evenly changed, a conical outer surface is produced, which is called taper turning. If the tool contact point moves in a way that changes the radius, then a workpiece with a contour like a ball is produced; or if the workpiece is short enough and the support is very rigid, then the forming tool normally feeds one outside the axis of rotation. Surfaces can be produced, and short tapered or cylindrical surfaces can also be formed.Flat surfaces are often required and they can be produced by radial turning of tool contact points with respect to the axis of rotation. It is easier to fix the tool and place the workpiece under the tool for larger workpieces while planing. The tool can feed reciprocally. The forming surface can be produced by a forming tool.Multi-blade cutters can also be used. Using a double-edged groove drilling depth is 5-10 times the hole diameter. Regardless of whether the drill rotates or the workpiece rotates, the relative motion between the cutting edge and the workpiece is an important factor. During milling, a rotating tool with many cutting edges comes into contact with the workpiece and the workpiece slowly moves relative to the tool. Flat or shaped surfaces may occur depending on the tool geometry and feed method. A horizontal or vertical axis rotation can be generated and can be fed in any of three coordinate directions.Basic machineThe machine tool produces parts with special geometry and precise dimensions by removing chips from plastic material. The latter is waste, which is a change from the long continuous strip of plastic material such as steel, which is useless from a processing point of view. It is easy to handle cracked chips produced from cast iron. The machine performs five basic metal removal processes: turning, planing, drilling, and milling. All other metal removal processes are modified from these five basic procedures. For example, boring is internal turning; reaming, tapping and counterboring are further machining of drilled holes; gear machining is based on Milling operation. Polishing and sanding are deformations that grind and remove the abrasive process. Therefore, there are only four basic types of machine tools that use specially controllable cutting tools: 1. Lathes, 2. Drilling machines, 3. Milling machines, 4. Grinding machines. The grinding process forms chips, but the geometry of the abrasive particles is uncontrollable.The amount and speed of material removal through various processing steps is enormous, just as high facets are removed in large turning operations, or in extremely small grinding and ultra-precision machining. A machine tool fulfills three major functions: 1. It supports work pieces or fixtures and tools 2. It provides relative motion to work pieces and tools 3. In each case provides a range of feeds and generallyup to 4-32 species Speed choices.Processing speed and feedSpeed, feed, and depth of cut are three major variables in economic processing. The other quantities are tapping and tool material, coolant and tool geometry. The speed of the metal removal and the power required are dependent on these variables.Depth of cut, feed, and cutting speed are the mechanical parameters that must be established in any metalworking process. They all affect the force, speed and speed of metal removal. The cutting speed can be defined as the radius of the velocity recording surface that spreads radially at any instant during one revolution, or the distance between two adjacent grooves. The depth of cut is the depth of entry and the depth of the trench.Turning in the center of the latheBasic operations completed on a motorized bed have been introduced. Those operations that use a single point tool on the outside surface are called turning. In addition to drilling, reaming, and grinding of internal surfaces, the operation is done by a single point tool. All machining operations, including turning, can be categorized as roughing, finishing or semi-finishing. Finishing removes a large amount of material as quickly and efficiently as possible, while a small part of the material left on the workpiece is used for finishing. Finishing isThe workpiece gets the final size, shape and surface accuracy. Sometimes semi-finishing leaves a predetermined amount of material for finishing, which is prior to finishing.In general, longer workpieces are simultaneously supported by one or two lathe centers. Conical holes, so-called center holes, are drilled at both ends for the center of the lathe - usually along the axis of the cylindrical workpiece. The end of the workpiece near the frame is usually supported by the center of the tailstock. At the end near the main bearing is the center of the main bearing or clamped by the jaw plate. This method can firmly tighten the workpiece and can smoothly transmit the force to the workpiece. The auxiliary support provided by the chuck to the workpiece reduces the chattering tendency during cutting. If the chuck can be carefully and accurately used to support the workpiece, then Accurate results can be obtained.Supporting the workpiece between two centers can give very accurate results. One end of the workpiece has been machined, then the workpiece can be turned. The other end is machined on a lathe, and the center hole serves as a precise positioning surface and a supporting surface for carrying the weight of the workpiece and resisting the cutting force. When the workpiece is removed from the lathe for any reason, the center hole will accurately return the workpiece to this lathe or another lathe or a cylindrical grinder. Workpieces are not allowed to be clampedon the main bearing by the chuck and lathe center. However, the first thing that comes to mind is a method of quickly adjusting the workpiece on the chuck, but this is not allowed because it is impossible to hold the center of the lathe while holding it by the chuck. The adjustment provided by the center of the lathe will not continue and the claw plate pressure will damage the center hole and lathe center, and even the lathe spindle. The floating claw plate provides an exception to the above statement. It is used almost exclusively for high production work. These chucks are real job drivers and are not used for the same purpose as ordinary three-jaw, four-jaw chucks.While large-diameter workpieces are fashioned in two centers, they are preferably held by the panel at the tail of the main bearing for smooth energy conversion; many lathe chucks do not provide sufficient energy conversion, although they can be used as special energy conversions.Mechanical processing introductionAs a method of producing a shape, machining is the most commonly used and the most important method in all manufacturing processes. The machining process is a process of producing a shape in which the drive device removes some of the material on the workpiece as chips. Although in some cases, the workpiece is supported using mobile equipment without support, most machining operations are performed by equipment that supports both the workpiece and the tool.Small batch, low cost. Machining has two applications in the manufacturing industry. Casting, forging, and pressure work produce each special shape, even one part, almost always with a higher mold cost. The shape of the weld depends largely on the raw material. By using equipment that has a high overall cost but does not have a special mold, machining is possible; starting from almost any kind of raw material, the shape is designed from any material as long as the external dimensions are large enough. Processing is therefore the preferred method. When producing one or several parts or even in mass production, the design of the parts logically leads to the casting, forging or stamping of the product. High precision, surface accuracy. The second application of mechanical machining is based on the possible high precision and surface accuracy. If mass production occurs in other processes, many low-volume components will produce low but acceptable tolerances. On the other hand, many parts produce general shapes from some large deformation processes and are only machined on selected surfaces with very high accuracy. For example, the inside process is seldom produced by any other machining method and the hole on the part may be processed immediately after the pressure operation.The main cutting parametersThere are four factors that fully describe the relationship between the basic tooling work during cutting: tool geometry, cutting speed and depthof cut. The tool must be made of a suitable material; it must have a certain strength, roughness, hardness and fatigue resistance. The tool geometry is described by face and angle and is correct for each cutting operation. Cutting speed refers to the speed at which the cutting edge passes through the work surface, which has been expressed in feet per minute. For machining efficiency, the cutting speed must be of an appropriate scale relative to the particular working combination. In general, the harder the work, the lower the speed. Feed is the rate at which the tool enters the workpiece. When the workpiece or tool rotates, the feed rate is in inches per revolution. When the tool or workpiece moves back and forth, the unit of feed is inches. In general, the feed rate is inversely proportional to the cutting speed in other similar situations. The cutting speed is expressed in inches and is represented by the distance the tool enters the workpiece. It refers to the width of the chips when turning or the thickness of the chips when cutting in a straight line. The depth of cut during roughing is greater than the depth of cut during finishing.Effect of Cutting Parameter Change on Cutting TemperatureIn metal cutting operations, heat is generated in the primary and secondary deformation zones and these results in complex temperatures throughout the tool, workpiece, and chips. A typical isothermal as shown in the figure, it can be seen that as predicted, when the workpiece materialundergoes major deformation and is reduced, there is a very large temperature gradient throughout the entire width of the chip. When the chips in the second deformed zone still have a short distance, the maximum temperature is reached.Because almost all of the work is done with metal cutting converted to heat, it can be predicted that the increased energy consumption per unit volume of metal removed will increase the cutting temperature. Therefore, when all the other parameters are unchanged, the rake angle becomes larger and the energy and cutting temperature per unit volume of metal removed will be reduced. When considering the increase in the thickness and speed of the non-formed chips, the situation is even more complicated. Increasing the thickness of the cut will often greatly affect the amount of heat transferred to the workpiece, the number of tools, and will keep the chips at a fixed amount, and at the same time the change in cutting temperature will be small. However, increasing the cutting speed will reduce the amount of heat transferred to the workpiece. This will increase the temperature rise of the main deformation of the chips. In addition, the second deformation zone is relatively small, and in this deformation zone it will increase the temperature. The other changes in cutting parameters hardly affect the removal of energy consumption per unit volume and the cutting temperature. It has thus been shown that even small changes in cutting temperature have a significant effect on toolwear rate, and it is appropriate to estimate the cutting temperature from the cutting data. The most direct and accurate method of testing high-speed steel tools, Trent gave detailed information on the temperature distribution of high-speed steel tools. This technique is based on the data detection of high-speed steel tools and is related to the microscopic changes in thermal history.Trent has described the measurement of cutting temperature and the temperature distribution of high-speed steel tools when machining a wide range of workpieces. Using scanning electron microscopy to study fine-scale microstructure changes, this technique has been further developed. This technique is also used to study the temperature distribution of high-speed steel single-point turning tools and twist drills.Tool wearBrittle fractures have been treated and there are basically three types of tool wear. Back flank wear, boundary wear and flank wear. Face wear occurs at the major and minor cutting edges. The main cutting edge is responsible for the removal of large amounts of metal, which increases the cutting force and temperature, and if left unchecked the vibration of the tool and the workpiece can be caused, and this can no longer be cut efficiently. The secondary cutting edge determines the workpiece size and surface finish. Wear of the flank causes poor surface accuracy in a large number of products. According to the actual cutting conditions, the mainreason for the unacceptable use of the tool is that the wear of the main flank before the secondary flank is very large, which results in the generation of an unacceptable portion. Due to the stress distribution of the tool, the frictional force in the sliding area is maximized between the chip and the surface at the beginning of sliding, and the final frictional force is zero. Therefore, abrasive wear occurs in this area. More wear occurs between the chip and the disengagement area adjacent to the area, which is more than adjacent to this point.This results in a localized pitting of the tool face at a certain distance from the face, which is usually partly arc-shaped. In many respects and based on actual cutting conditions, the boundary wear is a less severe wear than the flank, so that the wear of the face is a relatively common blunt standard. Then, as various authors have shown, with the increase of cutting speed, the increase of surface temperature is more than the increase of the blade surface, and because the temperature change seriously affects any type of wear rate, boundary wear usually occurs at higher cutting speeds. Situation.Where the tool is in contact with the uncut surface, the wear of the trailing portion of the main flank is more pronounced than that along the remaining wear surface. This is because the local influences such as the uncut surface are caused by the work hardening caused by the previous cutting, oxidation scale, and local high temperature. This localized wearis generally related to the wear of the boundary and is sometimes severe. Although the occurrence of a notch does not seriously affect the cutting performance of the tool, the notch is often deeper, and it is likely that the cutting tool will break if it continues.If any form of gradual wear continues to make its dramatic existence, the tool will face catastrophic failures, such as the cutting tool can not be cut, in good condition, the workpiece is scrapped, at worst, the mechanical tool may cause damage. For cemented carbide tools and various types of wear and tear, the maximum service life limit is reached before a catastrophic failure occurs. However, wear on high-speed steel cutting tools is uneven. It has been found that when wear continues and even catastrophic failure occurs, the most meaningful and reproducible results are obtained, but in practice, the cutting time is much less. At the time of failure. Several phenomena occur when a catastrophic failure occurs. The most common is a sudden increase in cutting force, a bright ring in the workpiece, and a significant increase in noise.Surface finishing mechanismThere are five basic mechanisms that affect the processed product: (1) The basic geometry of the cutting process, the single-point turning tool will advance axially a constant distance, the resulting surface will be on it, and the tool will feed in the vertical direction. A series of sharp points form the basic shape of the cutting tool. (2) The efficiency ofcutting. It has already been mentioned that an unstable tumor will produce a face that contains hardened tumor segments. This fragment reduces the surface finish. It can also be proved that under heavy cutting conditions, large feed rates, small rake angles and low cutting speeds can be used. In addition to these, the production conditions can also lead to unstable BDE products. The cutting process becomes unstable rather than continuous cutting in the shear zone. , Shattered, uneven discontinuous chips appear, and the surface is not smooth enough. This is especially true when working with ductile materials. (3) The stability of the machine tool. According to certain combinations of cutting conditions, workpiece dimensions, clamping methods and stiffness relative to the machine structure, instability is a tool-induced chatter. Under certain conditions, this kind of vibration will reach and maintain a certain amplitude, and vibrations based on other conditions will also be generated, unless the cutting prevents considerable damage or both the cutting tool and the workpiece may vibrate. This phenomenon is called chattering.Axial turning features a long spiral band on the workpiece and short pitch fluctuations on the temporary machined surface. (4) Remove the effectiveness of cuttings. In intermittent chip production processes, such as milling and turning of brittle materials, it is expected that whether due to gravity or cutting fluid, chips will leave the cutting zone and in any case will not affect the cutting surface. Consecutive chips are obvious,and if no measures are taken to control the chips, they may affect the cutting surface and leave marks. Inevitably, this marks only expectations.(5) The effective relief angle of the cutting tool. For small cutting edges and relief angles with a certain geometry, it is possible to cut at the main cutting edge and polish at the secondary cutting edge. This will result in good surface accuracy, but of course this combination of strictly metal forming cannot be recommended as an actual cutting method. However, due to occasional occurrence of these conditions, tool wear can cause changes in the surface properties.Limits and tolerancesMechanical parts are manufactured so they are interchangeable. In other words, each mechanical part or device is made to a size and shape suitable for other types of machines. In order to make the parts interchangeable, each part is dimensioned to fit the corresponding part in the right way. This is not only impossible, but it is impractical to make many parts into one size. This is because the machine is not perfect and the tool wears. A slight deviation from the correct size is usually allowed. The size of this deviation depends on the type of part being manufactured. For example, a part may be 6 inches and the upper and lower deviation is 0003 inches (one thousandth of a thousandth). So this deviation can be between 5,997 inches and 6003 inches and still maintain the correct size. This is bias. The difference between the upper and lower deviations is theThe tolerance is the maximum amount of change in part size, and the basic size is the size limit derived from the allowable variation and tolerance range. Sometimes the deviation allows only one direction to change. It allows the tolerance to change in the hole or axis without seriously affecting the fit. When the tolerance changes in both directions, it is called full deviation (positive and negative). The full deviation is separate and there will be on each side of the basic size. The limit size is only the largest size and the smallest size. Therefore, the to lerance is the difference between these two dimensions.Surface accuracy and size controlProducts have been completed in their proper shape and size, and often require some type of surface accuracy to enable them to perform their own functions. In some cases, in order to resist scratching and scratching, it is necessary to improve the physical properties of the surface material. In many manufacturing processes, dirt, chips, grease or other harmful substances are left on the surface of the product. Mixtures of different materials, the same materials processed in different ways, may require some special surface treatment to provide a uniform appearance.基本加工工序和切削技术Shunmugam M基本加工的操作机床是从早期的埃及人的脚踏动力车和约翰·威尔金森的镗床发展而来的。
机械类英文文献+翻译
机械类英文文献+翻译20.9 MACHINABILITYThe machinability of a material usually defined in terms of four factors:1、Surface finish and integrity of the machined part;2、Tool life obtained;3、Force and power requirements;4、Chip control.Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.20.9.1 Machinability Of SteelsBecause steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels.Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels.Phosphorus in steels has two major effects. It strengthens the ferrite, causingincreased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with built-up edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous stringy ones, thereby improving machinability.Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In non-resulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and alumin um and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section 32.11) and is smeared over the tool-chip interface du ring cutting. This behavior has been verified by the presence of high concentra tions of lead on the tool-side face of chips when machining leaded steels.When the temperature is sufficiently high-for instance, at high cutting spee ds and feeds (Section 20.6)—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Le aded steels are identified by the letter L between the second and third numeral s (for example, 10L45). (Note that in stainless steels, similar use of the letter L means 〝low carbon,〞a condition that improves their corrosion resistance.)However, because lead is a well-known toxin and a pollutant, there are se rious environmental concerns about its use in steels (estimated at 4500 tons of lead consumption every year in the production of steels). Consequently, there is a continuing trend toward eliminating the use of lead in steels (lead-free ste els). Bismuth and tin are now being investigated as possible substitutes for lea d in steels.Calcium-Deoxidized Steels. An important development is calcium-deoxidize d steels, in which oxide flakes of calcium silicates (CaSo) are formed. These f lakes, in turn, reduce the strength of the secondary shear zone, decreasing tool-chip interface and wear. Temperature is correspondingly reduced. Consequently, these steels produce less crater wear, especially at high cutting speeds.Stainless Steels. Austenitic (300 series) steels are generally difficult to mac hine. Chatter can be s problem, necessitating machine tools with high stiffness.However, ferritic stainless steels (also 300 series) have good machinability. M artensitic (400 series) steels are abrasive, tend to form a built-up edge, and req uire tool materials with high hot hardness and crater-wear resistance. Precipitati on-hardening stainless steels are strong and abrasive, requiring hard and abrasio n-resistant tool materials.The Effects of Other Elements in Steels on Machinability. The presence of aluminum and silicon in steels is always harmful because these elements com bine with oxygen to form aluminum oxide and silicates, which are hard and a brasive. These compounds increase tool wear and reduce machinability. It is es sential to produce and use clean steels.Carbon and manganese have various effects on the machinability of steels, depending on their composition. Plain low-carbon steels (less than 0.15% C) c an produce poor surface finish by forming a built-up edge. Cast steels are mor e abrasive, although their machinability is similar to that of wrought steels. To ol and die steels are very difficult to machine and usually require annealing pr ior to machining. Machinability of most steels is improved by cold working, w hich hardens the material and reduces the tendency for built-up edge formation.Other alloying elements, such as nickel, chromium, molybdenum, and vana dium, which improve the properties of steels, generally reduce machinability. T he effect of boron is negligible. Gaseous elements such as hydrogen and nitrog en can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions; the higher the oxygen content, the lower the aspect ratio an d the higher the machinability.In selecting various elements to improve machinability, we should consider the possible detrimental effects of these elements on the properties and strengt h of the machined part in service. At elevated temperatures, for example, lead causes embrittlement of steels (liquid-metal embrittlement, hot shortness; see Se ction 1.4.3), although at room temperature it has no effect on mechanical prop erties.Sulfur can severely reduce the hot workability of steels, because of the fo rmation of iron sulfide, unless sufficient manganese is present to prevent suchformation. At room temperature, the mechanical properties of resulfurized steels depend on the orientation of the deformed manganese sulfide inclusions (aniso tropy). Rephosphorized steels are significantly less ductile, and are produced so lely to improve machinability.20.9.2 Machinability of Various Other MetalsAluminum is generally very easy to machine, although the softer grades te nd to form a built-up edge, resulting in poor surface finish. High cutting speed s, high rake angles, and high relief angles are recommended. Wrought aluminu m alloys with high silicon content and cast aluminum alloys may be abrasive; they require harder tool materials. Dimensional tolerance control may be a pro blem in machining aluminum, since it has a high thermal coefficient of expans ion and a relatively low elastic modulus.Beryllium is similar to cast irons. Because it is more abrasive and toxic, t hough, it requires machining in a controlled environment.Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating to ols with high toughness. Nodular and malleable irons are machinable with hard tool materials.Cobalt-based alloys are abrasive and highly work-hardening. They require sharp, abrasion-resistant tool materials and low feeds and speeds.Wrought copper can be difficult to machine because of built-up edge form ation, although cast copper alloys are easy to machine. Brasses are easy to ma chine, especially with the addition pf lead (leaded free-machining brass). Bronz es are more difficult to machine than brass.Magnesium is very easy to machine, with good surface finish and prolong ed tool life. However care should be exercised because of its high rate of oxi dation and the danger of fire (the element is pyrophoric).Molybdenum is ductile and work-hardening, so it can produce poor surfac e finish. Sharp tools are necessary.Nickel-based alloys are work-hardening, abrasive, and strong at high tempe ratures. Their machinability is similar to that of stainless steels.Tantalum is very work-hardening, ductile, and soft. It produces a poor surf ace finish; tool wear is high.Titanium and its alloys have poor thermal conductivity (indeed, the lowest of all metals), causing significant temperature rise and built-up edge; they can be difficult to machine.Tungsten is brittle, strong, and very abrasive, so its machinability is low, although it greatly improves at elevated temperatures.Zirconium has good machinability. It requires a coolant-type cutting fluid, however, because of the explosion and fire.20.9.3 Machinability of Various MaterialsGraphite is abrasive; it requires hard, abrasion-resistant, sharp tools.Thermoplastics generally have low thermal conductivity, low elastic modul us, and low softening temperature. Consequently, machining them requires tools with positive rake angles (to reduce cutting forces), large relief angles, small depths of cut and feed, relatively high speeds, and proper support of the work piece. Tools should be sharp.External cooling of the cutting zone may be necessary to keep the chips f rom becoming 〝gummy〞and sticking to the tools. Cooling can usually be a chieved with a jet of air, vapor mist, or water-soluble oils. Residual stresses m ay develop during machining. To relieve these stresses, machined parts can be annealed for a period of time at temperatures ranging from to ( to ), and th en cooled slowly and uniformly to room temperature.Thermosetting plastics are brittle and sensitive to thermal gradients during cutting. Their machinability is generally similar to that of thermoplastics.Because of the fibers present, reinforced plastics are very abrasive and are difficult to machine. Fiber tearing, pulling, and edge delamination are significa nt problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful rem oval of machining debris to avoid contact with and inhaling of the fibers.The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processi ng parameters, such as ductile-regime cutting (Section 22.4.2).Metal-matrix and ceramic-matrix composites can be difficult to machine, d epending on the properties of the individual components, i.e., reinforcing or wh iskers, as well as the matrix material.20.9.4 Thermally Assisted MachiningMetals and alloys that are difficult to machine at room temperature can be machined more easily at elevated temperatures. In thermally assisted machinin g (hot machining), the source of heat—a torch, induction coil, high-energy bea m (such as laser or electron beam), or plasma arc—is forces, (b) increased too l life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter.It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machi ning are in the turning of high-strength metals and alloys, although experiment s are in progress to machine ceramics such as silicon nitride.SUMMARYMachinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends n ot only on their intrinsic properties and microstructure, but also on proper sele ction and control of process variables.20.9 可机加工性一种材料的可机加工性通常以四种因素的方式定义：1、分的表面光洁性和表面完整性。
文献翻译-非传统的加工工艺
外文资料翻译NON-CONVETIONAL MACHININGNon-conventional machining has been well known in ceramics processing due to their high productivity and cost effectiveness. In the past，many researchers have studied machining of advanced ceramics conducted by chemical machining(CM), electrical discharge machining(EDM)，laser beam machining(LBM) and ultrasonic machining(USM)．Non—conventional machining utilizes other forms of energy different from mechanical energy. The energies used in non—conventional machining are thermal energy, chemical energy and electrical energy.Chemical machining is one of the oldest micromachining technologies．This process applies reactive enchants to remove unwanted part from the work piece surface. It is a corrosive-controlled process. Many studies have been done on CM to investigate its etching rate, surface roughness and dimensional accuracy. CM includes photochemical machining. PCM is a method of fabricating component using reactive etchings to corrosively oxidize selected areas of the component. This process can produce highly complex products with very fine details, at high accuracy and low cost. They present a number of advantages，such as simple set up，quick preparation and no tool required; hence problems such as tool wear, machine tool deflections, vibrations and cutting forces are eliminated. In addition, chemical machining minimizes the effect of ceramics brittleness and low fracture. Disadvantages of chemical machining include chemical disposal，the presence of uncontrollable parameters, especially material structure and their rate of chemical reaction with solutions. In addition, high attention is required during processing. ZUBEL studied the silicon anisotropic etching process in water solution of KOH and TMAH with and without both organic and inorganic addition．This study shows that the etching rate is affected by the attendance of organic and inorganic agents．KIM employed the etching process with alower oxygen gas flow ratio and found that this action reduces etching damage to the low—k materials.Abrasive water jet (AWJ) is a technique that involves forceful impingement of abrasive particles to achieve the removal of surface material. AWJ depends on the water jet pressure ，stand—off distance，abrasive type’s size and flow rate. However, these choices are significantly affected by extreme factors such as the machined material structure and geometry of the jet nozzle. The most common advantage of AWJ is that it yields little heat during machining process therefore no heat affected zone(HAZ) happens，hence the process does not require heat treatment and no damage is reported．Compared with traditional machining technologies. AWJ offers the following advantages：fast speed，able to cut thick material，good accuracy, finishing surface and it cuts virtually anything with no HAZ．Unfortunately, some burr will occur near the cutting area. AWJ is widely used in metal, glass, ceramic，marble and granite cutting machines. GI and GI made a conclusion in their research that AWJ had a great potential as a machining method for brittle and hard materials. Unfortunately, they found a large—scale fracture that easily developed on the backside of the work piece and affected surface finish. Although AWJ has been recognized as the most efficient method to machine ceramics , result showed that the damage in surface always happens in the lower zone of the surface , where a lot of pits were found and lower the surface quality. To overcome this problem，a new cutting head oscillation technique has been introduced. This technique applied to the cutting process produces superior results and shows that the smooth zone depths increase by more than 30％with oscillation as compared with that without oscillation. However, a further study is required to reduce the pits effect that occurs at the lower surface layer.Electrical discharge machining uses spark erosion to remove small particles from electrically conductive material.The acceleration of EDM material removal rate increases with the discharge current and working voltage, but decreases with increasing pulseduration. EDM is especially well—suited for cutting intricate contour that would be difficult to produce with traditional machining. Advantages of EDM include high dimensional accuracy, good surface finish，lack of burr .Ti3SiC2 with excellent electrical conductivity and thermal conductivity is easily machined by EDM but high power is needed. In order to obtain a high material removal rate and better surface roughness，LIU suggested using a suitable chemical additive, dielectric strength，washing capability and viscosity of the machining fluid. They also suggested using a water-based emulsion as the machining fluid as harmful gas is not generated during machining，and the equipment is not corroded. Another suggestion by MUTTAMARA to improve the material removal rate is by employing positive polarity in the case where the conductive layer is sufficient. Study on the EDM of conductive ceramics shows EDM performance is purely dependent on the level of intensity. It has been observed that increasing intensity will tend to increase surface roughness and electrode wear.HU investigated EDM on Ti3SiC2 using water as dialectic and found typical thermal shock cracks and loose grains in subsurface, which result in about 25％of strength degradation. Results of EDM reveal a wide variation in removal rates and surface finishes, as shown in 4 and 5 shows the material removal and tool wear for EDM under roughing condition；and Fig-6 indicates the TIB surface after EDM.Electrochemical discharge machining(ECDM)is a modification of EDM. Materials are removed or deposited with the transferring of ions based on the anodic dissolution mechanism, so that high precision is achievable and it has the feasibility of micromachining. In order to obtain better machining accuracy and smaller machining size，many research works have been done on electrolyte, electrode’s insulation and systematic control of machining process. BHATTAC HARYYA found that the machining rate and accuracy could be enhanced through effective and precise control of the spark generation. Taper side wall and flat front tool tip are the most effective parameters for controlled machining. The advantages of ECDM include higher material removal rate , use of nontoxic electrolyte components withvery little changes in their composition during operation ，minimal waste disposal ，monitoring and control of electrolyte .Laser assisted machining is a thermal process. The laser is used as a heat source with the beam focused on the un—machined section of the work piece .The addition of heat softens the surface layer of the material, so ductile deformation happens rather than brittle deformation during cutting. LAM power requirements depend largely on the material and the nature of the machining process. In LAM ，cutting force is obviously significantly reduced and the ease of cutting is increased accordingly ，resulting in evident improvement in surface roughness. The possibility of vaporizing material during LAM may cause surface problems due to its severity in much the same way as in discharge machining. The advantages of laser are that it provides high speed and precise cut when cutting thin material ；Laser yields no burr and a little HAZ. LAM has demonstrated its ability to reduce cutting force and lower dynamic forces，less sharp segmented chip and smooth surface finish is produced .It is suitable to cut non—reflection mild steel．LAM disadvantages include it requires high energy, high cost and must be conducted in a specify condition .The power of laser must be controlled properly to obtain a satisfactory result and a lot of power is needed to conduct this machining .CHANG and KUO showed that LBM clearly appropriate for predicting the temperature distribution of difficult—to—machine materials during the LAM process．Tool wear is a major factor affecting the surface roughness of the work piece．Data shows the comparison of tool wear in LAM with conventional machining. They found that cutting resistance of processing aluminum oxide ceramics is extremely large, thus increasing the tool wear and affecting surface quality. BLACK showed that surface glaze usually possesses a different linear expansion rate to the underlying substrate．The large thermal gradient due to laser beam causes the lower substrate to expand at a different rate，resulting in cracking of the glaze．Ultrasonic machining (USM) is a process where material is removed primarily by repeated impact of the abrasive particles .the main parameters, which are staticforce, vibration amplitude, and grit size, have significant effects on the material removal rate .Material removal occurs when the abrasive particles, suspended in the slurry between the tool and work piece, impact the work piece due to the down stroke of the vibrating tool. It is mentioned in many reports that, for deeper cut, a vacuum-assist to ensure adequate flow of the suspension is strongly recommended. Another type of USM is rotary ultrasonic machining .The difference between USM and RUM is the tool used. USM uses a soft tool and slurry loaded with hard abrasive particles, while in RUM the hard abrasive particles are handed on the tools .The major advantage of USM is that it is a non-thermal, non-chemical, and non—electrical process．Therefore，metallurgical，chemical or physical properties of work piece remain unchanged．However, in USM．The material removal rate is considerably slow and even stops as penetration depth increases；the slurry may wear away the wall of the machined hole as it passes back towards the surface，which limits the accuracy; and considerable tool wear happens，which in turn makes the process very difficult to hold close tolerances. Efforts have also been made to develop models to predict the material removal rate in RUM from control variables. ZENG concluded that RUM tools could be designed in a way so that the lateral face is shorter. Tools with shorter latter face use less diamond grains and hence lower manufacturing cost.非传统的加工工艺非传统加工已得到很好的处理，由于其高效率及成本效益陶瓷闻名。
超精密磨削加工技术外文翻译文献
超精密磨削加工技术外文翻译文献超精密磨削加工技术外文翻译文献超精密磨削加工技术外文翻译文献(文档含中英文对照即英文原文和中文翻译)原文：Precision internal grinding with a metal-bonded diamondgrinding wheelJun Qian, Wei Li, Hitoshi OhmoribNanjing University of Aeronautics and AstronauticsAbstractA metal-bonded grinding wheel, compared with conventional grinding wheels, offers the advantage of high hardness, high holding ability and finer usable abrasive grit mesh sizes. The truing and dressing of a metal-bonded diamond (MBD) wheel, in practice, are very difficult. To grind small-diameter internal cylindrical surface with MBD-wheels, an interval electrolytic in-process dressing (ELID) method was utilized. Experiments were carried out on an ordinary cylindrical grinding machine with an attached internal grinding set-up, and straight type grinding wheels of different grit sizes were used. The grinding wheels were trued, using the electrical discharge method, and the effects of electrode shapes, grinding parameters, and grit sizes were evaluated experimentally. Mirror surface grinding of different materials was carried out with a #4000 CIB-D wheel, incorporated with this interval ELID (ELID II) method. The experimental results are reported # 2000 Elsevier Science S.A. All rights reserved.Keywords:Cylindrical grinding; Metal-bonded grinding wheel; Dressing; Electrolytic in-process dressing；Precisiongrinding1. IntroductionAlong with the technological advancement of ultra-precision grinding, applications and requirements for precision cylindrical surfaces have increased significantly in the recent years [1]. As a principal processing method for an internal surface, cylindrical grinding has been commonly utilized as a final operation in the production of precision components. Since grinding is usually the most costly of all manufacturing processes, considerable attempts have been focused on the analysis and optimization of the grinding process to minimize machining time [2-6], and on various compensatory control strategies to improve workpiece quality[7-10]in the cylindrical grinding. However, few researches on mirror-surface internal grinding have been reported [5,6,11], probably due to the limitation of abrasive grit size applicable to non-metallic bond grinding wheels [5,7,8,10].Research on high efficiency grinding of advanced materials, by utilizing high-rigidity grinding machines and tough metal-bonded superabrasive wheels, has led to the successful development of cast iron bonded diamond (CIB-D) grinding wheels [12]. These wheels are manufactured by mixing diamond grits, cast iron powder or fiber, and a small amount of carbonyl iron powder. The wheels are compacted to a desired form under high pressure and then sintered in an atmosphere of ammonia. These wheels are not suitable for continuous grinding for a long period of time for the following reasons: (1) As tougher metal-bonded wheels exhibit poor dressing ability, it is difficult to achieve efficient and stable dressing simultaneously. (2) Higher rate of material removal in the grinding promotes wear of the abrasive grains, therefore, more frequent redressing of thegrinding wheel will be required by stopping the grinding process.(3) While machining metals such as steel, wheel loading (embedding of swarf) occurs, making effective dressing of metallic bond wheel difficult in practice. Although a diamond slab incorporated with an abrasive jet sharpening method is able to dress a bronze-bonded wheel to the same topography as an electroplated wheel [12], complex equipment must be added inevitably which cause working-environment problem. Dressing by electrical discharge is a good method, but it is difficult to conduct on-line dressing, and dressing stripes appear on the wheel periphery when a pair of parallel electrodes is used [13,14]. Electrolytic in-process dressing (ELID) has so far served as the most successful dressing method for metal-bonded wheels. It has been devised and applied successfully in precision surface grinding [15-17]. However, its application to internal grinding has not been well investigated; especially when the internal diameter of the workpiece is just slightly larger than that of the grinding wheel, it is very difficult or even impossible to fix a dressing electrode mounted parallel to the wheel surface as in ordinary ELID grinding [15]. A novel method to carry out ELID grinding of internal cylindrical surfaces on an ordinary grinding tool is presented in this paper. The principle and process of this method, namely interval ELID (ELID II) grinding, is also discussed. Applying ELID II grinding to an ordinary grinding machine, some preliminary experiments have been carried out. Two types of dressing electrodes were used and their dressing effects were investigated. With this technology, four specimens of alumina ceramic, hardened steels SKH51 and SKD11 and bearing steel, were ground to mirror finish. The results of this research are presented in the following sections.2. Principle of interval ELID grindingThe interval dressing of an abrasive grinding wheel itself is not a new technology. In fact, using the common mechanical dressing methods, the wheel is usually dressed at intervals. The grinding process is stopped to dress the wheel after grinding one workpiece or several work pieces. The tool life limit can be chatter vibration, surface roughness and burning marks, etc. [2]. However, with the ELID II method, the wheel is dressed at intervals and the abrasives remain protruding, enabling the grinding process to go on without any interruption and consequently realizing high efficiency grinding.The interval ELID system is essentially composed of thefollowing elements: (i) a metal-bonded grinding wheel, (ii)an ELID power source, (iii) electrolytic coolant, and (iv) a pipe dressing electrode.The most important feature of this process is that no special machine is required, and in fact the experimental system we used is an auxiliary internal cylindrical grinding attachment on an external cylindrical grinder.The fundamental principle of interval ELID grinding is same as that of ordinary ELID grinding [15]. Fig. 1 shows a schematic diagram of the interval ELID grinding system. The metal-bonded grinding wheel, which is electrically conductive, is connected to the positive terminal of a DC-pulse power supplFig. 1. Schematic diagram of interval ELID grinding.-y with a smooth brush contact, and a fixed electrode is made negative. A proper clearance of approximately 0.1 mm is originally set between the positive pole (wheel) and the negative one (dressing electrode). By virtue of electrolysis between twoelectrodes, the wheel and the dressing electrode, the grinding wheel is dressed and a non-conductive film is formed on the wheel periphery. This occurs upon the supply of current from the power source and the electrically conductive coolant. During the interval ELID grinding process, the protruding grains grind the workpiece and as a result, the grains and the oxide layer wear down. The wheel's electrical conductivity increases, due to the wear of the non-conductive oxide layer. The current in the circuit increases, thus increasing the electrolysis. The abrasive grains therefore become more protruding and an insulating layer is formed.3. Experimental procedureUsually, interval ELID grinding consists of the following steps.(i) Truing: truing is required to reduce the initial eccentricity of the wheel, especially when a new wheel is used for the first time. It is difficult to apply conventional truing methods, such as brake dresser, to metallic bond wheels due to the high bond strength. In this investigation, the cast iron bonded wheel was trued by the electrical discharge (ED) process. (ii) ELID dressing, also known as pre-dressing by electrolysis, presently performed at a much lower wheel rotation speed and higher electric settings. (iii) Grinding: intervalELID grinding. The conditions of electrolysis, during the last two steps, differ due to change in the wheel state and grinding conditions.3.1. ED-truingTo true a cast iron bonded diamond wheel at high speed and with high precision, an electrical discharge truing (ED-truing) method was used in this study. Fig. 2 shows the details of this method. A special ED-truing wheel,made of high temperaturealloy and insulated from its central shaft, was mountFig. 2. View of the ED-truing set-up.-ed on the three-jaw chuck of the grinding tool. The ED-truing wheel was connected to the negative pole of an ELID power source originating from ordinary ED power supply, whilst the grinding wheel was linked to the positive pole. Both the ED-truing wheel and the grinding wheel, especially the latter, rotated at a fairly low speed and the ED truing wheel reciprocated along with the machine's saddle. Little and sometimes even no coolant was supplied to the working area to prevent electrolysis to the full and to pursue high truing precision.3.2. Pre-dressingFollowing the ED-truing, pre-dressing was carried out before starting ELID grinding (see Fig. 1). When the pre-dressing began, the surface of the trued wheel showed a good electrical conductivity. Therefore, the current would be very high and the voltage between the wheel and electrode would be low, varying in accordance with the wheel size and dressing settings. After several minutes, the cast iron fiber bond material, which is mostly ionized into Fe+2, is dissolved by electrolysis. The ionized Fe+2 will react with nonconductive ferrous hydroxides and oxides to form a layer on the wheel periphery. This insulating oxide layer would grow on the wheel surface, whereby its electrical conductivity would be reduced. Consequently, the current would decrease and the working voltage would remain quite high (90 V, in case that the originally set open voltage is 100 V) after 20 min. The color of the wheel change-d to dark pink, due to the formation of ferrous oxide.3.3. Interval ELID grindingDuring the grinding process, the protruding grains grind the workpiece and as a result, the grains and the oxide layer, wear down. The wheel's electrical conductivity increases, due to the wear of the oxide layer. The current in the circuit increases, accelerating the electrolysis, making the abrasive grains more protruding and forming an insulating layer. In the case of internal cylindrical grinding, the metal-bonded grinding wheel is dressed at intervals, i.e. the wheel is dressed when it departs away from the workpiece. When very fine grit size abrasive wheel is used and the infeed rate is very low, the insulating layer and the abrasive can finish the work surface in a way similar to lapping, achieving a super smooth surface.4. ConclusionsInternal surface grinding with metallic bond grinding wheels, incorporated with electrolytic in-process dressing, was carried out on an ordinary grinding tool. Pipe and arcdressing electrodes were used first to verify their dressing effects and some experiments were conducted to optimize the grinding parameters. Finally, mirror internal surface grinding was accomplished on both metallic materials and alumina ceramic. Based on these experiments, the following conclusion were down:(1) The pipe dressing electrode is superior to electrodes of other shapes in the case of internal grinding with ELID.(2) The grinding conditions have the same effects on grinding qualities in ELID II grinding as in ordinary cylindrical grinding.(3) Mirror internal surface grinding is practicable on ordinary grinding machine using cast iron bonded diamond (CIB-D) wheels with ELID II.5.References[1] B. Komanduri, D.A. Lucca, Y. Tani, Technological advances in fine abrasive processes, Ann.CIRP 46 (2) (1997) 545-589.[2] J. Peters, R. Aerens, Optimization procedure of three phase grinding cycles of a series withoutintermediate dressing, Ann. CIRP 29 (1) (1980) 195-199.[3] S. Malkin, Y. Koren, Optimization infeed control for accelerated spark-out in plunge grinding,ASME J. Eng. Ind. 106 (1984) 70-74.[4] H.K. Toenshoff, M. Zinngrebe, M. Kemmerling, Optimization of internal grinding bymicrocomputer-based force control, Ann. CIRP 35 (1) (1986) 293-296.[5] G. Xiao, S. Malkin, K. Danai, Autonomous system for multistage cylindrical grinding, ASME J.Dyn. Syst. Meas Control 115 (1993) 667-672.[6] G. Xiao, S. Malkin, On-line optimization for internal grinding, Ann. CIRP 45 (1) (1996) 287-292.[7] I. Inasaki, Monitoring and optimization of internal grinding process, Ann. CIRP 40 (1) (1991)359-362.[8] H. Kato, Y. Nakano, Transfer of roundness error from center and center hole to workpiece incylindrical grinding and its control, Ann. CIRP 34 (1) (1985) 287-290.[9] Y.S. Liao, L.C. Shiang, Computer simulation of self-excited and forced vibrations in the externalcylindrical plunge grinding process, ASME J. Eng. Ind. 113 (1991) 297-304.[10] K.H. Kim, K.F. Eman, S.M. Wu, Development of aforecasting compensatory control system forcylindrical grinding, ASME J. Eng. Ind. 109 (1987) 385-391.[11] E. Salje, H.-H. Damlos, H. Mohlen, Internal grinding of high strength ceramic workpiece materialswith diamond grinding wheels, Ann. CIRP 34 (1) (1985) 263-266.[12] T. Nakagawa, Y. Hagiuda, K. Karimori, Cast iron bonded diamond grinding tool and itsapplication to hard materials, in: Proceedings of the Fifth ICPE, Tokyo, 1984.[13] K. Suzuki, T. Uematsu, T. Nakagawa, On-machine truing/dressing of metal bond grinding wheelsby electric-discharge machining, Ann. CIRP 36 (1) (1987) 115-118.[14] J.Tamaki,K.Takahashi,M.Kubota, Electrical dressing of metal bonded grinding wheels, in:Proceedings of the ISEM-X, 1992, pp. 510-515.[15] H.Ohmori, T.Nakagawa, Mirror surface grinding of silicon wafers with electrolytic in-processdressing, Ann. CIRP 39 (1) (1990) 329-332.[16] H. Ohmori, Electrolytic in-process dressing (ELID) gridning technique for ultraprecision mirrorsurface machining, Int. J. Jpn. Soc. Prec. Eng. 26 (4) (1992) 273-278.[17] H. Ohmori, I. Takahashi, B.P. Bandyopadhyay, Ultra-precision grinding of structural ceramics byelectrolytic in-process dressing (ELID) grinding, J. Mater. Process. Technol. 57 (1996) 272-277.金属结合剂金刚石砂轮的精密内圆磨削摘要金属结合剂砂轮与传统砂轮相比，具有高硬度、高抓底能力以及更好的磨料粒度尺寸的优势。
切削技术-加工基础外文文献翻译、中英文翻译
外文资料CUTTING TECHNOLOGYIntroduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece.Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.Primary Cutting ParametersThe basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all otherparameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.Wears of Cutting ToolDiscounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and highertemperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds.At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture.If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, theworkpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset of catastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level.Mechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. These are:1、The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the workpiecc and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.2、The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.3、The stability of the machine tool. Under some combinations of cutting conditions; workpiece size, method of clamping ,and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under someconditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and workpiece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the workpiece surface and short pitch undulations on the transient machined surface. M4、The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking5、The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size arc derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is shown in only one direction from the nominal size. Unilateral tolerancing allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size it is known as a bilateral tolerance (plus and minus).Bilateral tolerancing is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions arc shown. Thus, the tolerance is the difference between these two dimensions.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance.Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of: environments. The type of protection procedure will depend largely upon the anticipated exposure, with dueconsideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a 'fitter' in the literal sense. J It is obvious that the two parts would have to remain together, and m the event of one having to be replaced, the fitting would have to be done all over again. In these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used 'off the shelf' to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, 'fiddling' operation, and it benefits the customer in the event of the need to replace worn parts.Automatic Fixture DesignTraditional synchronous grippers for assembly equipment move parts to the gripper centre-line,assuring that the parts will be in a known position after they arc picked from a conveyor or nest. However, in some applications, forcing the part to the centre-line may damage cither the part or equipment. When the part is delicate and a small collision can result in scrap, when its location is fixed by a machine spindle or mould, or when tolerances are tight, it is preferable to make a gripper comply with the position of the part, rather than the other way around. For these tasks, Zaytran Inc. Of Elyria, Ohio, has created the GPNseries of non- synchronous, compliant grippers. Because the force and synchronizations systems of the grippers are independent, the synchronization system can be replaced by a precision slide system without affecting gripper force. Gripper sizes range from 51b gripping force and 0.2 in. stroke to 40Glb gripping force and 6in stroke.GrippersProduction is characterized by batch-size becoming smaller and smaller and greater variety of products. Assembly, being the last production step, is particularly vulnerable to changes in schedules, batch-sizes, and product design. This situation is forcing many companies to put more effort into extensive rationalization and automation of assembly that was previously the case. Although the development of flexible fixtures fell quickly behind the development of flexible handling systems such as industrial robots, there are, nonetheless promising attempts to increase the flexibility of fixtures. The fact that fixtures are the essential product - specific investment of a production system intensifies the economic necessity to make the fixture system more flexible.Fixtures can be divided according to their flexibility into special fixtures, group fixtures, modular fixtures and highly flexible fixtures. Flexible fixtures are characterized by their high adaptability to different workpieces, and by low change-over time and expenditure.Flexible fixtures with form variability are equipped with variable form elements (e. g. needle - cheek, multileaf, and lamella - cheek), modular workpiece nonspecific holding or clamping - elements (e. g. , pneumatic modular holding - fixtures and fixtures kits with moveable elements), or with fictile and hardening media(e.g. ,panic late- fluidized - bed - fixtures and thermal clamping - fixtures).Independent of the flexibility of a fixture, there are several steps required to generate a fixture, in which a workpiece is fixed for a production task. The first step is to define the necessary position of the workpiece in the fixture, based on the unmachined or base pan, and the working features. Following this, a combination of stability planes must be selected. These stability planes constitute the fixture configuration in which the workpiece is fixed in the defined position, all the forces or torques are compensated, and the necessary access tothe working features is ensured. Finally, the necessary positions of moveable or modular fixture elements must be calculated- adjusted, or assembled, so that the workpiece is firmly fixed in the fixture. Through such a procedure the planning and documentation of the configuration and assembly of fixture can be automated.The configuration task is to generate a combination of stability planes, such that fixture forces in these planes will result in workpiece and fixture stability. This task can be accomplished conventionally, interactively or in a nearly fully automated manner. The advantages of an interactive or automated configuration determination are a systematic fixture design process, a reduction of necessary designers, a shortening of lead time and better match to the working conditions. In short, a significant enhancement of fixture productivity and economy can be achieved.With the full preparation of construction plans and a bill of materials, t time saving of up to 60% in achieving the first assembly can be realized. Hence, an aim of the fixture configuration process is the generation of appropriate documents.The following sections will describe a program procedure for automated fixture design and an application example.中文译文切削技术加工基础作为产生形状的一种方法，机械加工是所有制造过程中最普遍使用的而且是最重要的方法。
文献翻译原文-通过实验设计优化微注射成型工艺
编号：毕业设计(论文)外文翻译（原文）学院：机电工程学院专业：机械设计制造及其自动化学生姓名：学号：指导教师单位：姓名：职称：2014年 5 月26 日1.IntroductionMicro Injection Moulding (MIM) is a relatively new technology which is popular in the industry for micromanufacture because of its mass production capability and low component cost. In order to achieve the highest quality components with minimal costs using MIM it is important to understand the process and identify the effects of different independent parameters. One of the methods that can be employed to investigate the overall operation of MIM is Design of Experiments (DoE). In general, DoE can be used to collect data from any process and gain an understanding of the process through data analysis. This procedure can help to optimise the process and eventually lead to quality improvements.This paper is organized as follows. The MIM process is described in Section 2. In Section 3 the DoE is introduced. The collection of experimental data is explained in section 4 followed by results and dataanalysis in section 5. The discussion of results is presented in section 6. Finally the paper ends with conclusions given in section 7.2.Micro Injection Moulding (MIM)Micro-injection moulding [1] is a relatively new technology in the manufacturing world, and as such, it needs to be thoroughly investigated. According toMicro-powder injection moulding, conducted by Liu et.al. [2], micro-system technology were widely used in the new 21st century because of its successful applications in many different fields, e.g. in fluidic, medical, optical andtelecommunications. Presented with massproduction capability and low component cost, make the MIM technology to be one of the key production processes for micro manufacturing. The Components of MIM fall into one of the following two categories:Type A: Overall size less than 1mmType B: Micro feature less than 200um.Initial work on DoE and data analysis on MIM, conducted by Sha et. al. [3], primarily focused on the analysis of 5 different factors (the melt and mould temperature, injection speed, pressure and flow status) affecting the achievable aspect ratios in three different polymer materials. The aspect ratio is the ratio of a longer dimension to its shorter dimension of a specially designed micro feature for this experiment. Their study concluded that Melt Temperature (Tb) and Injection Speed (Vi) were the key factors affecting the aspect ratios achievable in replicating micro features in all three polymers materials.The effect of tool surface quality in MIM, conducted by Griffiths et. al. [4], primarily focused on the factors affecting the flow behavior and also the interaction between the melt flow and the tool surface.The findings of these earlier investigations are taken into consideration in this study.Fig 1 shows a picture of a MIM machine. The planning of DoE and the data analysis was carried out using the statistical software package “Minitab 16”.3.Design of Experiments (DoE)The technique of defining and investigating all possible conditions in an experiment involving multiple factors is known as the Design of Experiments.The two types of DoE that are widely used are the Factorial design and Taguchi Method. According to Minitab design of experiment [6], Factorial design is atype of designed experiment that allows for the simultaneous study of the effects that several factors may have on a response. When performing an experiment, varying the levels of all factors simultaneously rather than one at a time, allows for the study of interactions between the factors.In a full factorial experiment, responses are measured at all combinations of the experimental factor levels. The combinations of factor levels represent the conditions at which responses will be measured. Each experimental condition is called “run ”and the response measurement an observation. The entire set of runs is the “design”.To minimize time and cost, it is possible to exclude some of the factor level combinations. Factorial designs in which one or more level combinations are excluded are called fractional factorial designs.Fractional factorial designs are useful in factor screening because they reduce the number of runs to a manageable size. The runs that are performed are a selected subset or fraction of the full factorial design. But Roy [7] mentions that using full factorial and fractional factorial DoE may contribute to the following issues:●The experiments become unwieldy in cost andtime when the number of variable is large;●Two designs for the same experiment may yielddifferent results;●The designs normally do not permitdetermination of the contribution of each factor;●The interpretation of experiment with a largenumber of factors may be quite difficult.Hence, Taguchi method was developed in order to overcome some of these issues. Taguchi method is the technique of defining and investigating all possible conditions in an experiment involving multiple factors.Taguchi method was first introduced by Dr. Genichi Taguchi after the Second World War [8, 9]. He came up with three basic concepts [7]:1. Quality should be designed into the product and not inspected into it.2. Quality is best achieved by minimising the deviation from a target. The product should be so designed that it is immune to uncontrollable environmental factors.3. The cost of quality should be measured as a function of deviation from the standard and the losses should be measure system-wide.Dr. Taguchi setup a three stage process to achieve the enhancement of product quality by DoE based upon the concepts above, namely, System design, Parameter design, and Tolerance design.For the first stage, system design is to determine the suitable working levels of design factors. It includes design and test of a system based on selected materials, parts and nominal product/process parameters.Parameter design is for finding the factor level that can achieve the best performance of the product/process.The last stage which is the tolerance design is to decrease the tolerance of factors which is significantly affecting the product /process.A special set of arrays called Orthogonal Arrays (OAs) were constructed to lay out the experiment. The OA simplify the experiment design process. It is done by selecting the most suitable OA, assigning the factors to the appropriate columns, and describing the combinations of the individual experiments called the trial conditions.In this study a fractional factorial DoE was conducted in combination with Taguchi’ design concepts for quality enhancement.4.Collection of Experimental DataThe experiment was designed and set-up as defined by Sha, et. al. [10]. This aim of this experiment is to analyse the effects of six factors on the achievable aspect ratios and find the most significant factors in order to reach the optimal settings which would give the highest aspect ratios. Fig. 2 shows the test part with micro features in the form of legs with two level of width (W),200 or 500 um ,and depth(D), 700() or 100 um( ) where the features having the same depth, D1 or D2,were grouped on one side of the part.Three different materials, namely, semi-crystalline polymers such as polypropylene (PP), polyoxymethylene (POM) and an amorphous polymer such as acrylonitrilebutadiene-styrene (ABS) were in this study. The parameters investigated were barrel temperature (Tb), mould temperature (Tm), injection speed (Vi), holding pressure (Ph), the existence of air evacuation (Va) and the width (W) of micro-legs.The aspect ratios, i.e. the ratios between the length of the micro feature and their depths, D1 or D2, are measured during the experiment. The average values of 24 measured responses with the same W and D (two per part) while applying the process setting given in Table 1 are used in this study.5.Results and Data AnalysisA 2-level six factors fractional factorial design (26-2) was applied in this experiment. The DoE was used to identify the factors that were active and significant to study the filling of micro channels. The purpose of this exercise is to look at the results of the DoE responses in order to understand the process and select thesignificant factors with their appropriate settings which are necessary for optimal performance.5.1.ResultsThe measured experimental responses for the DoE for the ratios between the length of the melt fills and the depth of the channels, D1 or D2 are recorded in Table 2. The value of D1 and D2 shown on the table are the average values of 24 measurements.5.2.Data AnalysisThe statistical software package “Minitab 16” was used to analyse the results obtained from the experiment.The result of the analysis for PP for both the cases ofD1 and D2 is given in Table 3.In Table 3 the “Effect” column shows the positive or negative effect of the factor on the measured response. Hence the higher the effect the more significant the factor in consideration will be.The “effect” column determines the factors’ relative strength,the “p-values” determine which of the factors are statistically significant. In this study the values in the P column of the Estimated Effects and Coefficients table are used to determine which of the effects are significant. To make a decision concerning which factors are significant, further analysis is necessary and this will be discussed in the next section. A typical value for the significance was chosen to be 0.05 throughout this study.6.Discussion of ResultsThe above results were utilised to produce moreevidence to support the claims for strong factors whichmatter the most for the MIM process.Using = 0.05, for PP D1, the p-values found for Tb is 0.038 and Vi is 0.009 indicate that the main effects from these two single factors Tb and Vi are significant, i.e. their p-values are less than 0.05. These two single factors and their effects and other calculated values are highlighted in Table 3. In addition, the above results show that none of the two-way interactions are significant. This is clearly shown by the “Normal Plot of the Standardized Effects” (Fig3) and the “Pareto Chart of the Standardized Effects” (Fig 4).6.1. Normal Effects PlotA normal effects plot is used to compare the relative magnitude and the statistical significance of both main and interaction effects. As shown in Fig 3, Minitab draws a straight line to indicate where the points would be expected to fall if all effects were close to zero. Points that do not fall near the straight line usually signal factors with significant effects. Such effects are larger and generally go further away from the fitted straight line compared to the unimportant effects. By default, Minitab usea=0.05 and labels any effect that is significant. This is shown in Fig 3 by clearly marked labels for factors C and A. The factor C having a much greater weight on the MIM process for PP-D1 compared to factor A can also be seen on this graph.6.2. Pareto ChartA pareto chart of the effects is used to compare the relative magnitude and the statistical significance of both main and interaction effects. As shown in Fig 4, Minitab plots the factor effects in decreasing order of the absolute value of the effects. The reference line on the chart indicates which factor effects are significant. When your model contains an error term, by default, Minitab use a=0.05 to draw the reference line.The results in Fig 3 confirm the results displayed in Fig 4 as factors C and A are the only two factors that have passed the reference line, and factor C havinga much larger effect6.3. Main Effects PlotThe main effects plot shows the basic effect of changing the significant factors. These one-factor effects are called main effects. In this plot bigger main effect is depicted by a line with steeper slope compared to the effects contributed by less significant factors. To calculate main effects, Minitab procedure subtracts themean response at the low or first level of the factor from the mean response at the high or second level of the factor. It can be seen from Fig 5 that changing Vi from level 1 to 2 has a bigger main effect than changing Tb. This is depicted by a line with steeper slope for Vi.6.4. Interaction EffectsThe next step in the analysis is to look at the significant interactions. The two-way interaction effects calculated in Table 3 can be visually displayed on the interaction plot to see how big these effects are. An interaction plot shows the impact of two suspected interacting factors that changing the settings of one factor has on another factor. Because an interaction can magnify or diminish main effects, i.e. depending on whether the interaction is positive or negative, evaluating interactions is extremely important. While close to parallel lines indicate little or no interaction between the factors, intersecting lines signal an interaction. The amount of interaction is proportional to the angle of intersection, i.e. close to 90° portrays the strongest possible interaction.The interaction plot in Fig 6 shows that the response, i.e. the aspect ratio for Vi at 100 is higher than for Vi at 50 at both levels of Tb. However, it can be seen that the difference in aspect ratio between runs using Vi at 100 and runs using Vi at 50 at Tb set to 225 is much greater than the difference in aspect ratio between runs using Viat 100 and runs using Vi at 50 at Tb set to 200. This suggests that to get the highest aspect ratio Tb should be set at 225 while Vi is kept at 100.Similar analysis was carried out for PP D2. Likewise, the experimental results were analysed for POM and ABS for D1 and D2. The significant single factors and interaction factors for each of these different materials and the recommended settings for the selected significant factors are summarised in Table 4.This study shows that in most cases the aspect ratio is influenced by single factors except in POM-D2, ABS-D1 and ABS-D2 with a two-way interaction. In the case of PP-D1, Tb and Vi and for PP-D2, Vi only. For POM-D1, Tb, Tm, Vi and W and for POM-D2, Tb, Tm, Vi, W and TbXVi. When ABS was used for D1 the contributing factors were Tb, Vi, W and TmXPh; for D2 the significant factors were Vi, W and TmXPh. The entries shown in bold in Table 4 indicate the chosen settings for the significant factors. The shaded cells in Table 4 show two-way interaction between the factors.Using the process of elimination the critical factors for PP was identified as barrel temperature () and injection speed (), for POM as barrel temperature (), mould temperature (), injection speed () and width (W), and for ABS as barrel fixed at 75. Hence the factors holding pressure (Ph) and the existence of air evacuation (Va) can be ignored in the MIM process. This gives a full factorial of 4 trials for , 16 trials for POM and 8 trials for ABS. Further, as a result of this study, the optimal settings to achieve the highest aspects ratio for different materials used can be summarised as follows:●PP-D1: Tb at 225 and Vi at 100;●PP-D2: Vi at 100;●POM-D1: Tb at 200, Tm at 60, Vi at 100 and W●at 500;●POM-D2: Same as for D1 except W;●ABS-D1: Tb at 258, Vi at 100, W at 500 while●Tm is fixed at 75;ABS-D2: Vi at 100, W at 500 while Tm is fixed at 75.Confirmatory trials were conducted to verify the optimal performance for the above settings which have been identified theoretically and repeated 24 times and the average measured responses gave the best aspect ratios to be found so far. They are as follows: for PP and POM the best aspect ratio of 20 and for ABS it was 21.7.ConclusionsIn this paper an analytical method for understanding the MIM process and optimising the process parameters using DoE has been presented. A fractional factorial experiment with Taguchi’s quanlity concepts has been conducted in order to save time and effort in performing the trials. The data collected in the form of measured responses has been successfully analysed to identify the significant single factors as well as two-way interactions. Further, the optimal process parameter setting identified through DoE method for different materials used in the study have been validated by running confirmatory trials and the measured responses verified the theoretical results by achieving high aspect ratios for the optimal settings found for the MIM process parameters. The knowledge of MIM gained through this study will help understand and optimise Nano Injection Moulding (NIM) process [11]. AcknowledgementsThe authors would like to thank the EC FP7 FlexiTool project for supporting this work.References[1] Trotta, G., Surace, R., Modica, F., Spina, R., Fassi, I., 2011. Micro Injection Moulding of Polymeric Components,” AIP Conf. Proc. 2011; 1315:1273-8.[2] Liu, ZY, Loh, NH, Tor, SB, Khor, KA, Murakoshi, Y., Maeda, R., Shimizu, T., 2002. Micro-powder injection molding. J Material Processing Technology 2002; 127(2), p. 165.[3] Sha, B., Dimov, S., Griffiths, C., Packianather, MS, 2007. Investigation ofmicro-injection moulding: Factors affecting the replication quality. J Materials Processing Technology 2007; 183, p. 284.[4] Griffiths, CA, Dimov, SS, Brousseau, EB, Hoyle, RT, 2007. The effects of tool surface quality in micro-injection moulding. J Materials Processing Technology 2007; 189(1):, p. 418.[5] Griffiths, CA, Dimov, SS, Brousseau, EB, Chouquet, C., Gavillet, J., Bigot, S., 2010. Investigation of surface treatment effects in micro-injection-moulding. Int J Advanced Manufacturing Technology 2010; 47(1):, p. 99.[6] Minitab Handbook. 5th ed. Canada: Curt Hinrichs; 2005.[7] Roy, R., 1990. A Primer on the Taguchi Method. USA: VanNostrand Reinhold; 1990.[8] Sudhakar, PR., 1995. An Introduction to Quality Improvement Through Taguchi Methods. Quality 1995, p. 54.[9] Taguchi, G., 1996. The Role of D.O.E. For Robust Engineering:A Commentry. Int J Quality and Reliability Eng 1996; 12:, p. 73.[10] Sha, B., Dimov, S., Griffiths, C., Packianather, MS, 2007. Microinjection moulding: Factors affecting the achievable aspect ratios. Int J Adv Manuf Technoly 2007; 33, p. 147.[11] Zhang, N., Cormac, J., Byrne, CJ, Browne, DJ, Gilchrist, MD, 2012. Towards nano-injection molding. Materials Today 2012; 15(5), p. 216.。
机械加工外文翻译、中英文翻译、机械类外文文献翻译
机械加工外文翻译、中英文翻译、机械类外文文献翻译The engine lathe is an old but still useful metal removal machine with many desirable attributes。
While it is no longer commonlyXXX。
In today's n shops。
it has largely been XXX。
turret lathes。
and automatic XXX of single-point tooling for maximum metal removal。
and the use of form tools for finished products that are on par with the fastest processing XXX.When it XXX for the engine lathe。
it largely depends on the skill of the operator。
Design XXX part for n。
it is XXX.XXX cutting tools。
XXX ns。
as the machine can perform these ns in one setup。
They are also capable of producing parts with high n and accuracy。
XXX industries.Now more than ever。
n machining XXX of a specific method。
the XXX.When designing for low quantities。
such as 100 or 200 parts。
it is most cost-effective to use a XXX。
designers should aim to minimize the number of ns required.Another n for n XXX。
中英文文献翻译-切削加工工序和夹具设计
英文原文Cutting process and fixture designMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson's boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece depends on the shape of the tool and its path during the machining operation.Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning, if the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed.Flat or plane surfaces are frequently required. They can be generated by radial turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the workpiece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planning and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the workpiece under it as in planning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools.Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether thedrill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiece. Which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the workpiece may be in any of the three coordinate directions.Basic Machine ToolsMachine tools are used to produce a part of a specified geometrical shape and precise I size by removing metal from a ductile material in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: I turning, planning, drilling, milling, and grinding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning; reaming, tapping, and counter boring modify drilled holes and are related to drilling; bobbing and gear cutting are fundamentally milling operations; hack sawing and broaching are a form of planning and honing; lapping, super finishing. Polishing and buffing are variants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable geometry: 1. lathes, 2. planers, 3. drilling machines, and 4. milling machines. The grinding process forms chips, but the geometry of the abrasive grain is uncontrollable.The amount and rate of material removed by the various machining processes may be I large, as in heavy turning operations, or extremely small, as in lapping or super finishing operations where only the high spots of a surface are removed.A machine tool performs three major functions: 1. it rigidly supports the workpiece or its holder and the cutting tool; 2. it provides relative motion between the workpiece and the cutting tool; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case.Speed and Feeds in MachiningSpeeds, feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables.The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed (V) is represented by the velocity of- the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance of the needle radially inward per revolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves.Turning on Lathe CentersThe basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, the operations on internal surfaces are also performed by a single point cutting tool.All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material as rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to obtain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation.Generally, longer workpieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the workpiece-usually along the axis of the cylindrical part. The end of the workpiece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock center or held in a chuck. The headstock end of the workpiece may be held in a four-jaw chuck, or in a type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the workpiece accurately in the chuck.Very precise results can be obtained by supporting the workpiece between two centers. A lathe dog is clamped to the workpiece; together they are driven by a driver plate mounted on the spindle nose. One end of the Workpiece is mecained;then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece and to resist the cutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe, or in a cylindrical grinding machine. The workpiece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, and perhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work provide an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four-jaw chucks.While very large diameter workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplatejaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have.I ntroduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece.Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.Primary Cutting ParametersThe basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thicknesstends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.Wears of Cutting ToolDiscounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an over sized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds.At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture.If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the workpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset ofcatastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level.Mechanism of Surface Finish ProductionThere are basically five mechanisms which contribute to the production of a surface which have been machined. These are:(l) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the work price and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut.(2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum.(3) The stability of the machine tool. Under some combinations of cutting conditions; workpiece size, method of clamping ,and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and workpiece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the workpiece surface and short pitch undulations on the transient machined surface.(4)The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking.(5)The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics.Limits and TolerancesMachine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that will fit the mating part in the correct way. It is not only impossible, but also impractical to make many parts to an exact size. This is because machines are not perfect, and the tools become worn. A slight variation from the exact size is always allowed. The amount of this variation depends on the kind of part being manufactured. For examples part might be made 6 in. long with a variation allowed of 0.003 (three-thousandths) in. above and below this size. Therefore, the part could be 5.997 to 6.003 in. and still be the correct size. These are known as the limits. The difference between upper and lower limits is called the tolerance.A tolerance is the total permissible variation in the size of a part.The basic size is that size from which limits of size arc derived by the application of allowances and tolerances.Sometimes the limit is allowed in only one direction. This is known as unilateral tolerance.Unilateral to learning is a system of dimensioning where the tolerance (that is variation) is shown in only one direction from the nominal size. Unilateral to learning allow the changing of tolerance on a hole or shaft without seriously affecting the fit.When the tolerance is in both directions from the basic size it is known as a bilateral tolerance (plus and minus).Bilateral to learning is a system of dimensioning where the tolerance (that is variation) is split and is shown on either side of the nominal size. Limit dimensioning is a system of dimensioning where only the maximum and minimum dimensions arc shown. Thus, the tolerance is the difference between these two dimensions.Surface Finishing and Dimensional ControlProducts that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance.Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of: environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved.Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application of protective coatings, organic and metallic.In the early days of engineering, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until the desired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a 'fitter' in the literal sense. J It is obvious that the two parts would have to remain together, and m the event of one having to be replaced, the fitting would have to be done all over again. In these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations.When one part can be used 'off the shelf' to replace another of the same dimension and material specification, the parts are said to be interchangeable. A system of interchangeability usually lowers the production costs as there is no need for an expensive, 'fiddling' operation, and it benefits the customer in the event of the need to replace worn parts.Automatic Fixture DesignTraditional synchronous grippers for assembly equipment move parts to the gripper center-line, assuring that the parts will be in a known position after they arc picked from a conveyor or nest. However, in some applications, forcing the part to the center-line may damage cither the part or equipment. When the part is delicate and a small collision can result in scrap, when its location is fixed by a machine spindle , or when tolerances are tight, it is preferable to make a gripper comply with the position of the part, rather than the other way around. For these tasks, zaytran Inc. Of Elyria, Ohio, has created the GPN series of non- synchronous, compliant grippers. Because the force and synchronizations systems of the grippers are independent, the synchronization system can be replaced by a precision slide system without affecting gripper force. Gripper sizes range from 51b gripping force and 0.2 in. stroke to 40Glb gripping force and 6in stroke. Grippers。
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中文翻译在微细磨削过程中切削力建模与仿真作者：Asma Perveen & M. Rahman & Y. S. WongReceived: 16 July 2013 /Accepted: 16 December 2013 /Published online: 12 January 2014施普林格出版社伦敦2014摘要由于精密化的产品工艺要求增加，微细磨削采用微小刀具已经变得非常普遍。
此外，该工艺流程相比其他工艺过程有一个优势，尤其是作为最后一个工步。
微细磨削的加工质量会受到磨削过程中各种因素的影响，特别是通过机械力引起的。
因此，切削力预测模型可以指导进一步发展和优化这个工序。
虽然，已经有很多对传统磨削的研究，而对密磨削的知识积累却很少，由于它是一个新兴的研究领域这样的事实。
早期的磨削模型大多是基于参数，如砂轮和工件速度，切削深度和砂轮的粒度。
这些早期的模型阐述了磨粒从工件表面进入和切割的材料产生的磨削力对材料去除的比例关系。
然而，这些模型可能不适合微细磨削，由于微细磨削的材料去除方式是不同于宏观尺度的方法。
此外，由于用于脆性材料加工使用的小进给量，除了切削力犁切力也需要考虑因此，一种新的分析模型来分析微细磨削加工中的切削力，基于工序排列，工件材料的性能与微细磨削刀具形状。
精密加工晶粒尺寸效应已在本文提出的模型中仔细考虑。
因此，本方法允许的切削力的来源包括切屑形成力和犁切力。
在微细磨削加工方面的实验研究被继续，来验证所提出的预测模型。
的预测的切削力与实验数值表现了良好的相关性除了实验数值较高的切削深度和较低的进给速度。
此外，配对t检验进行了预测和实验之间的差异结果的量化。
关键词：切削力，晶粒，磨削，玻璃1引言磨削被认为是最古老的制造工艺，但它仍然被关注作为现代制造业的重要组成部分。
这是因为它作为最后一道工序，具有非常低的材料去除率。
这使得它最适合于生产高精度的表面质量的零件。
因此，可以预期的是，在过去几十年里磨削过程中已成为广泛研究的对象，特别是通过建模与仿真[ 1 ]。
基于理论分析和实证模型的过程中，各种类型的模拟在文献[2–4]。
由于随由于随机取向的个体磨粒在砂轮表面，常规磨削被看作是一个复杂的过程。
因此，为了使它更简单，大多数的磨削模型都是基于经验关系，主要工艺参数，如切削深度，从实验数据拟合得到速度比与等效直径的关系是通过一个指数和乘以一个系数。
基于对磨削力和砂轮平面面积磨损的实验结果，磨削力包括切削力和滑动摩擦力，是由Malkin和Cook[ 5 ]最先提出的。
Malkin [ 6 ]也验证了磨削过程中，包含大部分磨削参数的方程。
另一个磨削模型是建立在李和福提出了一个常规的车削切削力公式[ 7 ] 的基础上。
基于二维平面应变滑移线场理论和三维金字塔形的粗糙模型，Badger 和Torrance还提出了两种不同的磨削力模型，在磨粒与工件接触被视为一个刚性接触，并且机械运动受磨削角度、工件材料和砂轮间的摩擦系数影响[ 3 ]。
Hecker等人。
还提出另一个磨削力模型，其中切屑厚度被假定为一个Rayleigh概率粒度分布，并且概率粒度函数的参数要考虑运动学条件，材料性能，砂轮的组织结构和磨削过程中其他动态因素的影响[ 8 ]。
Hahn和Linsay提出了许多方面的磨削工艺实验和衍生的材料去除率，颤振，砂轮磨损，表面光洁度和几何形状之间的几个重要的定量关系[9–11 ]。
在这项研究中，获得了经验公式。
然而，在本文中的模型建立于实验数据上的。
在工业生产中，该实证模型已广泛地用于估算加工参数。
然而，在经验公式中，模型的每个指数和系数的校正是通过对不同的工件材料的组合，砂轮形状和磨削经验进行的耗时巨大又昂贵的运动学实验测试。
这个惯用的经验模型估算磨削过程的最佳结果的方法是根据不同的磨削条件的。
因此，切削刃情况的偶然性和对材料在极限状态下性能的未知，提供了研究第一个工件与单个磨粒相互作用的模型的动力。
建成后，该单颗磨粒相互作用模型可以推广到整个砂轮。
虽然，已经有很多对传统磨削的研究，而对密磨削的知识积累却很少，由于它是一个新兴的研究领域这样的事实。
这个精密型磨分享一些的与传统的研磨等方面。
它是好的众所周知，磨削过程是一个复杂的过程，因为其多切割点，也因为它的影响许多参数和。
早期的磨削模型大多是基于参数，如砂轮和工件速度，切削深度和砂轮的粒度。
这些早期的模型阐述了磨粒从工件表面进入和切割的材料产生的磨削力对材料去除的比例关系。
然而，这些模型可能不适合微细磨削，由于微细磨削的材料去除方式是不同于宏观尺度的方法。
此外，由于用于玻璃材料加工使用的小进给量，除了切削力，犁切力也需要考虑。
除了这些，还有金属磨削和微细磨削有许多不同的定制机制，如磨削的刀具，材料去除机理，磨损机制，玻璃加工和一些其他问题。
因此，金属磨削模型可能无法直接适用于脆性材料的磨削。
到目前为止，文献调查表明这种模型稀缺。
因此，要有一个新的模型，考虑到所有这些因素。
本研究试图建立一个用于脆性材料微细磨削工艺的模型[ 12 ]。
微细磨削过程显然是类似于传统的磨削的随机性。
它是一个独特的观点，单颗磨粒和工件之间是相互影响的。
所以考虑单颗磨粒的相互作用的分析模型是在微细磨削过程中的一个关键因素。
单颗磨粒相互作用可以描述成一个很大的负前角在高应变率下磨削。
尺寸效应可用于分析微细磨削和犁切机理，微细磨削过程中每个磨粒的摩擦力联合作用之间的关联[ 13，14 ]。
在微细磨削过程中力的产生与接触表面之间的实际面积、砂轮粒度和每个磨粒产生的力有关。
因此，该模型的发展可以分为如下几个步骤：·切屑形成的建模·单磨粒切削力建模·单磨粒犁切力建模·磨削力建模2切屑形成建模在切屑形成的过程中，研磨刀具形状对工具和工件之间的相互作用起着重要的作用。
在加工过程中,切削刃接触工件的大小是影响切削形成的最相关的刀具表面参数。
切削刃数目是估计整个刀具表面性能的基础。
例如，总磨削力可以用活性磨粒的数量乘以平均磨粒的力得到。
砂轮产生磨削加工的复杂性，其中包含各种磨料磨粒。
这些磨料在砂轮表面随机分布。
由于这种随机性，加工过程有了显著的变化。
另一方面，砂轮说明书里不会提到这些磨粒的粒度、大小和形状。
砂轮表面的分析可以估算总的磨削力，因为总磨削力与参与磨削的磨粒数量有很高的相关性。
有效磨粒数不仅取决于切削刃的静态密度也取决于砂轮的转动。
因此，利用切削刃粒度模型是合理的。
再次，动态切削刃的数量不仅取决于静态切削刃的分布也取决于磨削运动条件和动态磨削的效果。
静态切削刃数量取决于磨粒尺寸，孔隙率和修整轮条件。
静态切削刃粒度函数如下[ 15 ]：式中：Cs(z)是静态切割粒度（每平方毫米）A是常数Z车轮的径向距离（微米）。
由于内向偏角δ，方程的静态粒度（1）被修改，法向力是由磨粒接触产生的。
这种偏差是每一磨粒的局部效应。
因此，A和K都不是影响静态磨削粒度的原系数，而静态的磨粒分布函数为了考虑挠度而修正为如下[ 16 ]：因此，方程（1）可以写成如下：因为每一个有效切削刃材料在移走后，在有效切削刃后面和附近的磨粒就不能去除材料了，使有效切削刃减少。
有效的磨粒产生一个三维立体的效果降低了砂轮圆周上的有效体积。
因此，Hecker 等人推断出有效切削刃的粒度如下[ 15 ]：式中：Vt是砂轮与工件在圆周上接触的总体积Vsh是有效磨削刃产生的总体积Vsh/Vt t是磨削刃在其路径上去除材料比例，其结果即是有效磨削刃。
砂轮的磨削表面是否有效取决于砂轮与工件之间的接触。
运动的磨粒使参与磨削的磨粒数量增加了。
此外，微细磨削的好处是，单位面积磨粒粒度在整个过程中可以更均匀的去除材料。
电火花加工中使用修整后的聚晶金刚石（PCD）刀具，磨削刃的磨粒可以被视为球面形的，并且一个磨粒相当于一个切削刃。
等效球形磨粒的直径可以从刀具和工件之间的几何关系推断。
首先，关于磨粒直径可以推导出如下[ 17 ]：式中ac是磨粒磨削过程中最大的接触长度，bc是磨粒的宽度，dc是磨粒的直径。
当磨粒的磨削深度t是已知的，磨粒的平均直径dgeq能由以下公式推导出：通常，磨削过的磨粒的大小会比原来的小，但这种等效磨粒的切削刃的直径可以小于或大于磨粒的原始直径。
平均磨粒直径取决于磨粒的外形和磨粒的切削深度如图[15]。
垂直表面微细磨削与端面铣削相比，工件被送入刀具旋转的水平面。
图1显示垂直微细磨削过程中切削形成的形状和连续切削的刀具。
当磨粒进行近似圆形的路径运动时，未切屑厚度H从零增加到极大值。
每个磨粒的进给率计算为（V／CD（Z′）V），其中v是工作台进给， V是PCD刀具的旋转速度Cd zð 0 Þ是线性动态粒度。
从图1b，弧长L′可以写成如下：图1 a垂直平面磨削原理图，b切屑形成图其中t是切削深度。
现在，把dgeq值代入式（5）式（6）。
工件的宽度等于刀具的直径D时，微细磨削过程中切屑的长度L也可以从下面的等式计算：从等式（8）和（9）中推出L可以用下式计算：从图2中可以得出，切屑的截面积Am可以计算如下：现在，切屑的体积Vchip 可以通过横截面积Am和切屑长度l计算，如下：因此，切屑材料的体积 Volchip除去时间t后可以表示成如下形式：在相同加工时间t里的工件的材料去除量Vwp可以表示成如下：计算未变形的切屑厚度的另一种不同的方法是根据制作的材料在切割区产生的切屑和整体材料去除率之间的平衡。
因此，体积大小就是从等式（13）和（14）中取的未变形切屑厚度平均值[18】。
其中h =未变形的厚度， v =进给速度，V=主轴转速，B =工件宽度，D =刀具直径，Cd（z′）=动态磨削刃粒度。
从未变形的切屑层厚度中，可以得出两个连续的切削点的间距L。
如果用bc表示切削点的平均有效宽度，PCD刀具外缘上的所有切削点的数量Ng等于 Cd(z′) 乘以面积，面积是圆周长乘以有效切削宽度的值[6]。
图2 a是垂直微细磨削的计算原理图，b是实际的切屑形状，c是理想的切屑形状。
当间距可计算如下：因此，切屑的厚度h和切削刃数量Ng可以从这部分得出。
3微细磨削单粒磨削力建模Basuray等人，已经叙述犁切晶粒时刀具前角临界值。
根据几何关系，临界前角可以使切屑层变形最小切削刃半径为[ 19 ]：其中αCr的临界角，H是最小的切屑层厚度，dgeq是粒径当量直径。
在微细磨削，得到瞬时倾角几何关系如下：其中H是未变形切屑层。
上述最低未变形切屑厚度，精密切削机理可以用Merchant的模型代表每一个无穷小的元素。
让我们考虑一个未变形切屑层，DH元素，在刀具前角位置被切削，如图3[19】所示的切屑形成和推进力与摩擦和刀具前角的关系。
因此，增量精密切削力dfcgx在二维简化的结构可以表示为公式[ 21，22 ]：这里，dfcgx是增量的切削力，σ是材料的强度，β是摩擦角和ϕ剪切角。