外文翻译---机床主轴单元
附录A 英文原文
Machine tool spindle units
A.1 Introduction
Machine tool spindles basically fulfill two tasks:
rotate the tools (drilling, milling and grinding) or work piece (turning) precisely in space transmit the required energy to the cutting zone for metal removal
Obviously spindles have a strong influence on metal removal rates and quality of the machined parts. This paper reviews the current state.and presents research challenges of spindle technology.
A.1.1.Historical review
Classically, main spindles were driven by belts or gears and the rotational speeds could only be varied by changing either the transmission ratio or the number of driven poles by electrical switches.
Later simple electrical or hydraulic controllers were developed and the rotational speed of the spindle could be changed by means of infinitely adjustable rotating transformers (Ward Leonard system of motor control).The need for increased productivity led to higher speed machining requirements which led to the development of new bearings, power electronics and inverter systems. The progress in the field of the power electronics (static frequency converter) led to the development of compact drives with low-cost maintenance using high frequency three-phase asynchronous motors.Through the early 1980’s high spindle speeds were achievable only by using active magnetic bearings. Continuous developments in bearings, lubrication, the rolling element materials and drive systems (motors and converters) have allowed the construction of direct drive motor spindles which currently fulfill a wide range of requirements.
A.1.2. Principal setup
Today, the overwhelming majority of machine tools are equipped with motorized spindles. Unlike externally driven spindles, the motorized spindles do not require mechanical transmission elements like gears and couplings.
The spindles have at least two sets of mainly ball bearing systems. The bearing system is the component with the greatest influence on the lifetime of a spindle. Most commonly the motor is arranged between the two bearing systems.
Due to high ratio of ‘power to volume’ active cooling is often required, which is generally implemented through water based cooling. The coolant flows through a cooling sleeve around the stator of the motor and often the outer bearing rings.
Seals at the tool end of the spindle prevent the intrusion of chips and cutting fluid. Often this is done with purge air and a labyrinth seal.
A standardized tool interface such as HSK and SK is placed at the spindles front end. A clamping system is used for fast automatictool changes. Ideally, an unclamping unit (drawbar) which can also monitor the clamping force is needed for reliable machining. If cutting fluid has to be transmitted through the tool to the cutter, adequate channels and a rotary union become required features of the clamping system.
Today, nearly every spindle is equipped with sensors for monitoring the motor temperature (thermistors or thermocouples) and the position of the clamping system. Additional sensors for
monitoring the bearings, the drive and the process stability can be attached, but are not common in many industrial applications.
A.1.3. State of the art
Spindles with high power and high speeds are mainly developed for the machining of large aluminum frames in the aerospace industry. Spindles with extremely high speeds and low power are used in electronics industry for drilling printed circuit boards (PCB).
A.1.4. Actual development areas in industry
Current developments in motor spindle industrial application focus on motor technology, improving total cost of ownership(TCO) and condition monitoring for predictive maintenance Another central issue is the development of drive systems which neutralize the existing constraints of power and output frequency while reducing the heating of the spindle shaft.
Particular attention was paid to the increase of the reliable reachable rotational speeds in the past. However, the focus has changed towards higher torque at speeds up to 15,000 rpm. Because of Increased requirements in reliability, life-cycle and predictable maintenance the ‘condition monitoring’ systems in motor spin dles have become more important. Periodic and/or continuous observation of the spindle status parameters is allowing detection of wear, overheating and imminent failures.
Understanding the life cycle cost (LCC) of the spindles has steadily gained importance in predicting their service period with maintenance, failure and operational costs.
2. Fields of application and specific demands
Spindles are developed and manufactured for a wide range of machine tool applications with a common goal of maximizing the metal removal rates and part machining accuracy.
The work materials range from easy to machine materials like aluminum at high speeds with high power spindles, to nickel and titanium alloys which require spindles having high torque and stiffness at low speeds. Cutting work materials with abrasive carbon or fiber-reinforced plastics (FRP) content need good seals at the spindle front end.
Spindles for drilling printed circuit boards operate in the angular speed range of 100,000 to 300,000 rpm. The increase in productivity and speed in this application field over the last few years was possible with the development of precision air bearings.
Spindles used in die and mould machining have to fulfill the roughing operations (high performance cutting, HPC) at high feed rates as well as the finishing processes (high-speed cutting, HSC) at high cutting speeds. Depending on the strategy and the machinery of the mould and die shop either two different machine tools equipped with two different spindles are used or one machine is equipped with a spindle changing unit. Another possibility is to use a spindle which can fulfill both, HSC and HPC conditions, but this still remains a compromise regarding overall productivity.
Aerospace spindles are defined by high power as well as high rotational speeds. Today’s spindles allow a material removal rate(MRR) of more than 10 l of aluminum per minute.
Grinding is a finishing operation where high accuracy is necessary, which requires stiff spindles with bearings having minimum runout. The present internal cylindrical grinding spindles have a runout requirement of less than 1 mm.
Spindle units which are used mainly for boring and drilling operations require high axial stiffness, which is achieved by using angular contact bearings with high contact angles. On the contrary, high-speed milling operations use spindles with bearings having small contact angles in
order to reduce the dependency of radial stiffness on the centrifugal forces.
Contemporary machining centers tend to have multi functions where milling, drilling, grinding and sometimes honing operations can be realized on the same work piece. The bottleneck for the enhancement of the multi-technology machines is still the spindle, which cannot satisfy all the machining operations with the same degree of performance. Reconfigurable and modular machine tools require interchangeable spindles with standardized mechanical, hydraulic, pneumatic and electrical interfaces.
A.3. Spindle analysis
The aim of modeling and analysis of spindle units is to simulate the performance of the spindle and optimize its dimensions during the design stage in order to achieve maximum dynamic stiffness and increased material removal rate with minimal dimensions and power consumption. The mechanical part of the spindle assembly consists of hollow spindle shaft mounted to a housing with bearings. Angular contact ball bearings are most commonly used in high-speed spindles due to their low-friction properties and ability to withstand external loads in both axial and radial directions. The spindle shaft is modeled by beam, brick or pipe elements in finite element environment. The bearing stiffness is modeled as a function of ball bearing contact angle, preload caused by the external load or thermal expansion of the spindle during operation. The equation of motion is derived in matrix form by including gyroscopic and centrifugal effects, and solved to obtain natural frequencies, vibration mode shapes and frequency response function at the tool attached to the spindle. If the bearing stiffness is dependent on the speed, or if the spindle needs to be simulated under cutting loads, the numerical methods are used to predict the vibrations along the spindle axis as well as contact loads on the bearings.
Spindle simulation models allow for the optimization of spindle design parameters either to achieve maximum dynamic stiffness at all speeds for general operation, or to reach maximum axial depth of cut at the specified speed with a designated cutter for a specificmachining application. The objective of cutting maximum material at the desired speed without damaging the bearings and spindle is the main goal of spindle design while maintaining all other quality and performance metrics, e.g. accuracy and reliability.
doe s not always lead to accurate identification of the spindle’s dynamic parameters；
A.3.2. Theoretical modeling
Theoretical models are based on physical laws, and used to predict and improve the performance of spindles during the design stage. The models provide mathematical relation between the inputs F (force, speed) and the outputs q (deflections, bearing loads, and temperature). The mathematical models can be expressed in state space forms or by a set of ordinary differential equations. In both cases linear or nonlinear behavior of the spindles can be modeled.
A.3.2.1. Mechanical modeling of shaft and housing
Finite element (FE) methods are most commonly used to model structural mechanics and dynamics of the spindles. The method is based on discretization of the structure at finite element locations by partial derivative differential equations. The analysis belongs to the class of rotor-dynamic studies where the axis-symmetric shaft is usually modeled by beam elements, which lead to construction of mass (Me) and stiffness (Ke) matrices.
Timoshenko beam element is most commonly used because it considers the bending, rotary inertia and shear effects, hence leads to improved prediction of natural frequencies and mode shapes of the spindle .The element PIPE16 of the commonly known FEA software ANSYS is also
an implementation of the Timoshenko theory and use the mass matrix and stiffness matrix As an example in the finite element model in Fig. 1, the black dots represent nodes, and each node has three Cartesian translational displacements and two rotations . The pulley is modeled as a rigid disk, the bearing spacer as a bar element, and the nut and sleeve as a lumped mass. The spindle in this case has two front bearings in tandem and three bearings in tandem at the rear. The five bearings are in overall back-to-back configuration. The tool is assumed to be rigidly connected to the tool holder which is fixed to the spindle shaft rigidly or through springs with stiffness in both directions translation and rotation. The flexibility of the spindle mounting has to be reflected in the model of the spindle-machine system. Springs are also used between the spindle housing and spindle head, whose stiffness is obtained from experience.
Fig. 1. The finite element model of the spindle-bearing-machine-tool system
附录 B 中文翻译
机床主轴单元
B.1.介绍
机床主轴基本上完成两个任务：
在空间精确的旋转刀具（钻削，铣削，磨削）或工件（车削）。
把所需要的能量传递到切削区
很显然主轴对切削效率和机加工件的质量有很大影响，这篇文章评论了目前的状态和介绍了主轴技术的研究挑战。
B.2历史回顾
典型地，主轴是被皮带或齿轮驱动的，转速只能通过改变传动比或通过电器开关改变驱动级的数量来改变。
之后，简单的电气或液压控制器开始发展，主轴旋转速度通过无级调速方式来改变，要提高生产力就需要更高的速度，加工技术要求发展新型轴承，电力电子与逆变器系统。在致力于发展紧凑的电力电子（静止变频器）领域的进步
导致在使用高频三相异步电动机上的低成本维护，对于早在80年代的主轴，高转速只能利用磁力轴承来实现，在轴承，润滑，滚动材料和驱动系统(马达和转换器)领域的持续发展已经允许建造直接驱动电机主轴来满足目前各种需求如今，绝大多数机床都装配了点主轴。不同于外部驱动主轴，电主轴不需要像齿轮和接头一样的机械传动单元。
主轴至少有两套主要的球轴承系统。轴承系统是对主轴的寿命影响最大的组成部件。最常见的电机是安装在两个轴承系统之间。
而冷却主要是通过水冷。冷却剂流过电机定子周围的冷却套而还经常流过轴承外圈。
主轴末端的密封件防止碎屑及切削液的侵入，通常这些是做了空气净化的。
一个标准的工具接口例如HSK和SK是被放置在主轴前端的。一个夹紧系统是用于快速automatictool变化。理想情况下，一个可以控制夹紧力的未夹紧单元需要可靠的加工。如果切削液一定要通过刀具流到切削上，那么对应的轨道和旋转机构就要求具有夹紧系统的特点。
今天，几乎每个主轴都装配有用于监视电机温度(热敏电阻或热电偶)的传感器和定位夹紧系统。用于监测轴承的附加传感器，可以监测驱动过程的稳定性，但在许多工业领域却不太普遍。
B.1.3当前发展状况
大功率、高转速电主轴是为了加工用于航空、航天工业的大型铝制框架而发展起来的。高转速、低功率的电主轴用于电子工业为印刷电子版钻孔（PCB）
B.1.4工业方面的实际开发领域
当前电主轴的发展主要集中在电动机的技术，降低用于预防性维护监测的成本。另一个核心问题是为了减少主轴上的热量发展用于抵消存在的约束力和输出频率的驱动系统。
过去注意力主要放在增加可靠的旋转速度。如今，如今的关注点已经改变，朝着具有高转速（15000r/min）的同时还要有很高的转矩。由于在可靠性，产品生命周期和可预测维护方面需求的增加，电机主轴的状态监测系统变得越来越重
要。对主轴各状态参数的定期和或连续观测能够检测磨损、过热和即将发生的故障。
了解主轴的产品寿命周期费用对预测服务期间内的维护、故障和运行成本有很大帮助。
B.2.应用领域和具体需求
主轴被研制和制造的主要目的是实现金属切削效率和加工精度的最大化。
工件材料可以分门别类，包括简单的，例如像铝，要用具有高转速和大功率的主轴，还包括难加工的，例如镍钛合金，要求主轴除了具有较低的转速，还要具有较大的转矩和刚度。切削具有磨料碳或碳纤维塑料的工件材料要求主轴前端具有良好的密封性。
给电路板钻孔的主轴转速要控制在100 000到300 000转/每分钟。随着空气轴承的精度的不断提高，电机主轴应用领域的生产力和转速也在不断提高。
用于模具加工的主轴必须以很高的进给率完成粗轧机组操作(高性能切割、HSC)、以很高的切削速度完成切削过程（高切削速度，HSC）.依据磨具和压铸车间的实施策略和机械装置，可以是两个机床配备两个不同的主轴或一个机床配备一个主轴切换单元。另一种情况就是用一个主轴来同时完成高速切削和高性能切割，但生产力仍然保持合理的水平。
航空航天用的主轴要求具有大功率和高转速。如今的主轴要求材料切除率达到每分钟切除铝材料101个单位。
磨削是一个要求高精度的操作过程，需要轴承具有很小的摆动的刚性轴。目前的内部磨床主轴要求轴承摆动不超过1毫米。
主要用于钻孔的主轴单元要求具有很高的轴向刚度，这需要使用具有高接触角的角接触球轴承来实现。相反，高速铣削操作要使用有小接触角的轴承用以减少由于离心力引起的径向刚度变化。
现代加工中心往往具有多种功能如铣、钻、磨，有时珩磨操作可以在相同的工件上实现。提高机床先进性的瓶颈仍然是机床主轴，因为他不能在相同精度的条件下满足所有的操作。可重构和模块化的机床需要有规范化的机械、液压、气动、电气接口的可互换的主轴。
B.3.主轴分析
主轴单元的模型和分析的目标是为了实现最大的动态刚度，以最小的尺寸和功率增加材料去除率，在设计阶段模拟主轴的性能和优化它的尺寸。主轴装配的机械部件是由安装有轴承的空心主轴组成。角接触球轴承广泛用于高速主轴，由于其低摩擦性能和可以同时承受径向和轴向载荷的能力。主轴可以在有限元环境下用梁、块、或管道单元来模拟。轴承刚度可以用一个球轴承接触角的函数、在操作期间由主轴的外部负载或热膨胀所引起的预紧力来模拟。运动方程以矩阵的形式导出，包括陀螺和离心效应，还有得到了附在主轴上的工具的固有频率、振型的形状和频率响应函数。如果轴承刚度与速度有关，或如果主轴在切削载荷下模拟，数值方法用于预测沿主轴轴振动荷载和轴承上的接触载荷。
主轴仿真模型考虑了主轴设计参数的优化，目的是为了使主轴在全速运行时达到最大的动刚度，用一把指定的专用刀具用指定的速度实现最大轴向切削深度。在不损坏轴承和主轴的前提下以指定的速度，主轴设计的主要目标是实现切除材料的最大化，同时还要保证各项其他指标如精度和可靠性。
B.3.1实验模拟
一个现有的电主轴的动态行为是通过测量它的力和位移之间的频率响应函数得到的。在机械加工过程中，主轴结构会引起振动，可测量的频率响应函数可以用曲线来拟合，可用于预测固有频率、阻尼比和刚度值。频率响应函数的实验测量对于在加工工艺设计阶段评估动态刚度和确定切削颤振条件是实用的。然而，以下困难需要考虑在内：
（1）只需要测量旋转轴的一小部分就可行了，因此模拟整个主轴是不可能的；
（2）运算速度和温度主要影响特征值，但当主轴旋转时频率响应函数的测量是相当困难的；
（3）运用从测量的输入和输出数据中提取的参数进行曲线拟合或其他方法并不总是得到主轴动态参数的精确分析；
B.3.2理论模型
理论模型是基于物理定律，在设计阶段用来预测和改善主轴的性能。模型提供输入F（力，速度）和输出q（挠度，轴承载荷，和温度）之间的数学关系。数学模型可以用状态空间形式或通过一系列的微分方程来表达，在这两种方案中主轴的线性或非线性行为都可以被精确的模拟。
B.3.2.1轴和外壳的力学建模
有限元方法普遍适用于主轴的结构力学和动态模型。该方法是通过偏导数微分方程组在有限元区域基于结构的离散化。该分析属于转子动态研究的类型，具有对称性的轴通常用梁单元来模拟，可以得到质量和刚度矩阵。
Timoshenko梁单元最为常用，因为它考虑了弯曲、转动惯量和剪切的影响，因此对主轴的固有频率和模态形状的预测有很大帮助。普遍都知道的有限元分析软件ANSYS中PIPE16单元也是使用了Timoshenko理论与质量和刚度矩阵。
如图1中的有限元模型的一个实例，黑点代表节点，每个节点以笛卡尔坐标系参考都有三个平动自由度和两个旋转自由度。滑轮被视为刚性圆盘，轴承隔套作为杆单元，螺母和套筒作为集中质量，在这个方案中主轴前段有两个串联的轴承，主轴后端有三个串联的轴承。五个轴承总体上是背靠背安装的。主轴轴轴头之间使用了弹簧，它的刚度由实验获得。
图B1 机床—主轴—轴承系统的有限元模型
B.3.3角接触球轴承的建模
角接触球轴承（图11）普遍应用于高速主轴。为了保持径向和轴向的旋转精度和足够的刚度以满足基本的操作要求，轴承需要预紧来防止打滑。基本上，有两种类型的轴承预紧力：刚性预紧和恒预紧。
图B2 主轴的草图模型
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Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up
外文翻译--农村金融主流的非正规金融机构
附录1 RURAL FINANCE: MAINSTREAMING INFORMAL FINANCIAL INSTITUTIONS By Hans Dieter Seibel Abstract Informal financial institutions (IFIs), among them the ubiquitous rotating savings and credit associations, are of ancient origin. Owned and self-managed by local people, poor and non-poor, they are self-help organizations which mobilize their own resources, cover their costs and finance their growth from their profits. With the expansion of the money economy, they have spread into new areas and grown in numbers, size and diversity; but ultimately, most have remained restricted in size, outreach and duration. Are they best left alone, or should they be helped to upgrade their operations and be integrated into the wider financial market? Under conducive policy conditions, some have spontaneously taken the opportunity of evolving into semiformal or formal microfinance institutions (MFIs). This has usually yielded great benefits in terms of financial deepening, sustainability and outreach. Donors may build on these indigenous foundations and provide support for various options of institutional development, among them: incentives-driven mainstreaming through networking; encouraging the establishment of new IFIs in areas devoid of financial services; linking IFIs/MFIs to banks; strengthening Non-Governmental Organizations (NGOs) as promoters of good practices; and, in a nonrepressive policy environment, promoting appropriate legal forms, prudential regulation and delegated supervision. Key words: Microfinance, microcredit, microsavings。 1. informal finance, self-help groups In March 1967, on one of my first field trips in Liberia, I had the opportunity to observe a group of a dozen Mano peasants cutting trees in a field belonging to one of them. Before they started their work, they placed hoe-shaped masks in a small circle, chanted words and turned into animals. One turned into a lion, another one into a bush hog, and so on, and they continued to imitate those animals throughout the whole day, as they worked hard on their land. I realized I was onto something serious, and at the end of the day, when they had put the masks into a bag and changed back into humans,
组合机床毕业设计外文翻译
The Aggregate Machine-tool The Aggregate Machine-tool is based on the workpiece needs, based on a large number of common components, combined with a semi-automatic or automatic machine with a small number of dedicated special components and process according to the workpiece shape and design of special parts and fixtures, composed. Combination machine is generally a combination of the base, slide, fixture, power boxes, multi-axle, tools, etc. From. Combination machine has the following advantages: (1) is mainly used for prism parts and other miscellaneous pieces of perforated surface processing. (2) high productivity. Because the process of concentration, can be multi-faceted, multi-site, multi-axis, multi-tool simultaneous machining. (3) precision and stability. Because the process is fixed, the choice of a mature generic parts, precision fixtures and automatic working cycle to ensure consistent processing accuracy. (4) the development cycle is short, easy to design, manufacture and maintenance, and low cost. Because GM, serialization, high degree of standardization, common parts can be pre-manufactured or mass organizations outsourcing. (5) a high degree of automation, low labor intensity. (6) flexible configuration. Because the structure is a cross-piece, combination. In accordance with the workpiece or process requirements, with plenty of common parts and a few special components consisting of various types of flexible combination of machine tools and automatic lines; tools to facilitate modification: the product or process changes, the general also common components can be reused. Combination of box-type drilling generally used for processing or special shape parts. During machining, the workpiece is generally not rotate, the rotational motion of the tool relative to the workpiece and tool feed movement to achieve drilling, reaming, countersinking, reaming, boring and other processing. Some combination of turning head clamp the workpiece using the machine to make the rotation, the tool for the feed motion, but also on some of the rotating parts (such as the flywheel, the automobile axle shaft, etc.) of cylindrical and face processing. Generally use a combination of multi-axis machine tools, multi-tool, multi-process, multi-faceted or multi-station machining methods simultaneously, productivity increased many times more than generic tools. Since the common components have been standardized and serialized, so can be flexibly configured according to need, you can shorten the design and manufacturing cycle. Multi-axle combination is the core components of general machine tools. It is the choice of generic parts, is designed according to special requirements, in combination machine design process, is one component of a larger workload. It is based on the number and location of the machining process diagram and schematic design combination machine workpiece determined by the hole, cutting the amount of power transmission components and the design of each spindle spindle type movement. Multi-axle power from a common power box, together with the power box installed on the feed slide, to be completed by drilling, reaming and other machining processes. The parts to be processed according to the size of multi-axle box combination machine tool design, based on an original drawing multi-axle diagram, determine the range of design data,
【机械类文献翻译】机床
毕业设计(论文)外文资料翻译 系部： 专业： 姓名： 学号： 外文出处：English For Electromechanical (用外文写) Engineering 附件：1.外文资料翻译译文；2.外文原文。 指导教师评语： 此翻译文章简单介绍了各机床的加工原理，并详细介绍了各机床的构造，并对方各机床的加工方法法进行了详细的描述， 翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英 文资料打下了基础。 签名： 年月日注：请将该封面与附件装订成册。
附件1：外文资料翻译译文 机床 机床是用于切削金属的机器。工业上使用的机床要数车床、钻床和铣床最为重要。其它类型的金属切削机床在金属切削加工方面不及这三种机床应用广泛。 车床通常被称为所有类型机床的始祖。为了进行车削，当工件旋转经过刀具时，车床用一把单刃刀具切除金属。用车削可以加工各种圆柱型的工件，如：轴、齿轮坯、皮带轮和丝杠轴。镗削加工可以用来扩大和精加工定位精度很高的孔。 钻削是由旋转的钻头完成的。大多数金属的钻削由麻花钻来完成。用来进行钻削加工的机床称为钻床。铰孔和攻螺纹也归类为钻削过程。铰孔是从已经钻好的孔上再切除少量的金属。 攻螺纹是在内孔上加工出螺纹，以使螺钉或螺栓旋进孔内。 铣削由旋转的、多切削刃的铣刀来完成。铣刀有多种类型和尺寸。有些铣刀只有两个切削刃，而有些则有多达三十或更多的切削刃。铣刀根据使用的刀具不同能加工平面、斜面、沟槽、齿轮轮齿和其它外形轮廓。 牛头刨床和龙门刨床用单刃刀具来加工平面。用牛头刨床进行加工时，刀具在机床上往复运动，而工件朝向刀具自动进给。在用龙门刨床进行加工时，工件安装在工作台上，工作台往复经过刀具而切除金属。工作台每完成一个行程刀具自动向工件进给一个小的进给量。 磨削利用磨粒来完成切削工作。根据加工要求，磨削可分为精密磨削和非精密磨削。精密磨削用于公差小和非常光洁的表面，非精密磨削用于在精度要求不高的地方切除多余的金属。 车床 车床是用来从圆形工件表面切除金属的机床，工件安装在车床的两个顶尖之间，并绕顶尖轴线旋转。车削工件时，车刀沿着工件的旋转轴线平行移动或与工件的旋转轴线成一斜角移动，将工件表面的金属切除。车刀的这种位移称为进给。车
组合机床外文文献
Int J Adv Manuf Technol (2006) 29: 178–183 DOI 10.1007/s00170-004-2493-9
ORIGINAL ARTICLE
Ferda C. C ? etinkaya
Unit sized transfer batch scheduling in an automated two-machine ?ow-line cell with one transport agent
Received: 26 July 2004 / Accepted: 22 November 2004 / Published online: 16 November 2005 ? Springer-Verlag London Limited 2005 Abstract The process of splitting a job lot comprised of several identical units into transfer batches (some portion of the lot), and permitting the transfer of processed transfer batches to downstream machines, allows the operations of a job lot to be overlapped. The essence of this idea is to increase the movement of work in the manufacturing environment. In this paper, the scheduling of multiple job lots with unit sized transfer batches is studied for a two-machine ?ow-line cell in which a single transport agent picks a completed unit from the ?rst machine, delivers it to the second machine, and returns to the ?rst machine. A completed unit on the ?rst machine blocks the machine if the transport agent is in transit. We examine this problem for both unit dependent and independent setups on each machine, and propose an optimal solution procedure similar to Johnson’s rule for solving the basic two-machine ?owshop scheduling problem. Keywords Automated guided vehicle · Lot streaming · Scheduling · Sequencing · Transfer batches entire lot to ?nish its processing on the current machine, while downstream machines may be idle. It should be obvious that processing the entire lot as a single object can lead to large workin-process inventories between the machines, and to an increase in the maximum completion time (makespan), which is the total elapsed time to complete the processing of all job lots. However, the splitting of an entire lot into transfer batches to be moved to downstream machines permits the overlapping of different operations on the same product while work proceeds, to complete the lot on the upstream machine. There are many ways to split a lot: transfer batches may be equal or unequal, with the number of splits ranging from one to the number of units in the job lot. For instance, consider a job lot consisting of 100 identical items to be processed in a three-stage manufacturing environment in which the ?ow of its operations is unidirectional from stage 1 through stage 3. Assume that the unit processing time at stages 1, 2, and 3 are 1, 3, 2 min, respectively. If we do not allow transfer batches, the throughput time is (100)(1+3+2) = 600 min (see Fig. 1a). However, if we create two equal sized transfer batches through all stages, the throughput time decreases to 450 min, a reduction of 25% (see Fig. 1b). It is clear that the throughput time decreases as the number of transfer batches increases. Flowshop problems have been studied extensively and reported in the literature without explicitly considering transfer batches. Johnson [1], in his pioneering work, proposed a polynomial time algorithm for determining the optimal makespan when several jobs are processed on a two-machine (two-stage) ?owshop with unlimited buffer. With three or more machines, the problem has been proven to be NP-hard (Garey et al. [2]). Besides the extension of this problem to the m -stage ?owshop problem, optimal solutions to some variations of the basic two-stage problem have been suggested. Mitten [3] considered arbitrary time lags, and optimal scheduling with setup times separated from processing was developed by Yoshida and Hitomi [4]. Separation of the setup, processing and removal times for each job on each machine was considered by Sule and Huang [5]. On the other hand, ?owshop scheduling problems with transfer batches have been examined by various researchers. Vickson
1 Introduction
Most classical shop scheduling models disregard the fact that products are often produced in lots, each lot (process batch) consisting of identical parts (items) to be produced. The size of a job lot (i.e., the number of items it consists of) typically ranges from a few items to several hundred. In any case, job lots are assumed to be indivisible single entities, although an entire job lot consists of many identical items. That is, partial transfer of completed items in a lot between machines on the processing routing of the job lot is impossible. But it is quite unreasonable to wait for the
F.C. ?etinkaya (u) Department of Industrial Engineering, Eastern Mediterranean University, Gazimagusa-T.R.N.C., Mersin Turkey E-mail: ferda.cetinkaya@https://www.360docs.net/doc/8a17313034.html,.tr Tel.: +90-392-6301052 Fax: +90-392-3654029
机床加工外文翻译参考文献
机床加工外文翻译参考文献(文档含中英文对照即英文原文和中文翻译) 基本加工工序和切削技术 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。它们为工件和刀具提供刚性支撑并可以精确控制它们的相对位置和相对速度。基本上讲，金属切削是指一个磨尖的锲形工具从有韧性的工件表面上去除一条很窄的金属。切屑是被废弃的产品，与其它工件相比切屑较短，但对于未切削部分的厚度有一定的增加。工件表面的几何形状取决于刀具的形状以及加工操作过程中刀具的路径。 大多数加工工序产生不同几何形状的零件。如果一个粗糙的工件在中心轴上转动并且刀具平行于旋转中心切入工件表面，一个旋转表面就产生了，这种操作称为车削。如果一个空心的管子以同样的方式在内表面加工，这种操作称为镗孔。当均匀地改变直径时便产生了一个圆锥形的外表面，这称为锥度车削。如果刀具接触点以改变半径的方式运动，那么一个外轮廓像球的工件便产生了；或者如果工件足够的短并且支撑是十分刚硬的，那么成型刀具相对于旋转轴正常进给的一个外表面便可产生，短锥形或圆柱形的表面也可形成。
平坦的表面是经常需要的，它们可以由刀具接触点相对于旋转轴的径向车削产生。在刨削时对于较大的工件更容易将刀具固定并将工件置于刀具下面。刀具可以往复地进给。成形面可以通过成型刀具加工产生。 多刃刀具也能使用。使用双刃槽钻钻深度是钻孔直径5-10倍的孔。不管是钻头旋转还是工件旋转，切削刃与工件之间的相对运动是一个重要因数。在铣削时一个带有许多切削刃的旋转刀具与工件接触，工件相对刀具慢慢运动。平的或成形面根据刀具的几何形状和进给方式可能产生。可以产生横向或纵向轴旋转并且可以在任何三个坐标方向上进给。 基本机床 机床通过从塑性材料上去除屑片来产生出具有特别几何形状和精确尺寸的零件。后者是废弃物，是由塑性材料如钢的长而不断的带状物变化而来，从处理的角度来看，那是没有用处的。很容易处理不好由铸铁产生的破裂的屑片。机床执行五种基本的去除金属的过程：车削，刨削，钻孔，铣削。所有其他的去除金属的过程都是由这五个基本程序修改而来的，举例来说，镗孔是内部车削；铰孔，攻丝和扩孔是进一步加工钻过的孔；齿轮加工是基于铣削操作的。抛光和打磨是磨削和去除磨料工序的变形。因此，只有四种基本类型的机床，使用特别可控制几何形状的切削工具1.车床，2.钻床，3.铣床，4.磨床。磨削过程形成了屑片，但磨粒的几何形状是不可控制的。 通过各种加工工序去除材料的数量和速度是巨大的，正如在大型车削加工，或者是极小的如研磨和超精密加工中只有面的高点被除掉。一台机床履行三大职能：1.它支撑工件或夹具和刀具2.它为工件和刀具提供相对运动3.在每一种情况下提供一系列的进给量和一般可达4-32种的速度选择。 加工速度和进给 速度，进给量和切削深度是经济加工的三大变量。其他的量数是攻丝和刀具材料，冷却剂和刀具的几何形状，去除金属的速度和所需要的功率依赖于这些变量。 切削深度，进给量和切削速度是任何一个金属加工工序中必须建立的机械参量。它们都影响去除金属的力，功率和速度。切削速度可以定义为在旋转一周时
农村金融小额信贷中英文对照外文翻译文献
农村金融小额信贷中英文对照外文翻译文献(文档含英文原文和中文翻译) RURAL FINANCE: MAINSTREAMING INFORMAL FINANCIAL INSTITUTIONS By Hans Dieter Seibel Abstract Informal financial institutions (IFIs), among them the ubiquitous rotating savings and credit associations, are of ancient origin. Owned and self-managed by local people, poor and non-poor, they are self-help organizations which mobilize their own resources, cover their costs and finance their growth from their profits. With the expansion of the money economy, they have spread into new areas and grown in numbers, size and diversity; but ultimately, most have remained restricted in size, outreach and duration. Are they best left alone, or should they be helped to upgrade