毕设英语翻译

毕业设计论文

外文翻译

沈阳航空航天大学

A study on the development of center carrier type progressive die for U-bending part process

用于U形零件弯曲加工的中间载体级进模研发

过程的研究

院系航空航天工程学部

专业飞行器制造工程（钣金与模具）

班级94030203

学号2009040302077

姓名成骏

指导教师刘占军

职称

负责教师

沈阳航空航天大学

2013年1月

A study on the development of center carrier type

progressive die for U-bending part process

Abstract

The Center carrier-type progressive die for U-bending sheet metal production part is a very specific division. This study reveals the sheet metal forming process with multi-forming die by Cut off type feeding system.

Through the FEM simulation by DEFORM, it was accepted to U-bending process as the first performance to design of strip process layout.

The next process of die development was studied according to sequence of die development, i.e. die structure, machining condition for die making, die materials, heat treatment of partially die components, know-how and so on.

The feature of this study is the die development of scrapless progressive die of multi-stage through the Modeling on the I-DEAS program,components drawing on the Auto-Lisp, CAD/CAM application, ordinary machine tool operating and revision by tryout.

Keywords Center carrier type progressive die,FEM simulation.Strip process layout, Scrapless progressive die,U-bending process,Tryout

1 Introduction

The progressive die performs a series of fundamental sheet metal working at two or more stages during the press running to produce a production part as the strip stock moving through the die surface. Press working from the optimum die design and its making have been the purpose of mass production in the manufacturing field.

So, this study needs a whole of press tool data, our field experiences, and theoretical instructions. According to upper factors, this study could be achieved to the optimum die design through the FEM simulation, I-DEAS modeling, and practical method of die making.

Furthermore the aim of least defects could be obtained mostly by revision through the tryout .

2. Die design

2.1. Die developing system

Fig. 1 shows the network of die development system.

Fig. 1. Network of die developing system.

In this system, it can be known that the production engineering,die making technology, standardization, trouble shooting, man power, purchase, tool, material, etc. are connected with a software and hardware, related instructions of wide and deep technology and its theoretical background.

Fig. 2 shows one of die components drawing by existing Auto-Lisp program under the

AutoCAD and Window environment.

Fig. 2. Die component drawing by Auto-Lisp.

Something of the other die components design have followed to this method and experiences.

2.2. Strip process layout

The disposition of part on the strip feed unfolding was displayed with a constant area repeatedly.

Due to upper cause, it must be enough that the decision of strip feeding distance (advance, pitch) and disposition of each stage on the strip lay out are performed exactly. Our intention considered that the best utilization ratio of sheet metal can be obtained as taking the accurate strip process layout design through the theoretical calculation and field experiences.

This is the optimum method of initial die design. At this time we referred the web size on the strip from database and its related instructions.

Fig. 3. Flow chart of strip process layout design system.

Fig. 3 shows the flow chart strip process layout design system. For the design of strip process layout, the first step is how to decide the feeding method according to the quantity of production part, accuracy of production part, material properties, and material thickness, the second step is followed to this flow chart of Fig. 3. Fig. 4 showing the production part and its developing length (99 mm) used to the thick sheet metal (material: SPCC and thickness: 1.3 mm) production part. From the strip process layout designing method,we could design the following strip process layout as showing Fig. 5 by Fig. 4 production part drawing. The strip process layout was considered that the proper sizes are strip width, web-size, advance, notching allowance, etc.

Fig. 4. Drawing of production part and its developing length: (a) part drawing and (b) part

developing length.

Fig. 5. Drawing of strip process layout.

The first stage operates piercing, the second stage works piloting, the third stage works notching, fourth stage works piercing, and fifth stage performs piloting with a idleness.

The sixth stage is first bending stage, also seventh stage works piercing.

The eighth stage works U-bending as the second bending.We must take care of pilot damage or its fracture through the causes of dislocation on the every stage. The ninth stage is

idle stage. The 10th stage is sizing stage. The 11th stage works part cutting as a complete stage. After that, the strip process layout was obtained as a result in Fig. 5.

2.3. Clearance and gap

This experimental press working material is proper thickness as a just in 1.3mm (SPCC).

Therefore, the clearance is large amount of 0.05mm between punch edge and die edge for the piercing and notching, etc. At this time the burr at the cutted edge of sheet metal could be created minimized amount in actual production part as a tryout result.

The gap between punch and die wall for the U-bending was taken 1.1 times of material thickness by database and experiences.

2.4. FEM simulation

Fig. 6 shows the result of FEM simulation of U-bending corner by DEFORM programming.

Fig. 6. Result of FEM simulation by DEFORM: (a) operation 1 step 100 meshing, (b) operation 1 step 100 stress line contour, (c) operation 1 step 100

strain line contour, and (d) operation 1 step 100 damaged line contour.

At this time the parameters of supporting to FEM simulation by DEFORM programming are shown in Table 1.

Through Fig. 6a–d, it was predicted that the U-bending crack is not created by the parameter of sheet metal of SPCC as shown in Table 1 and the other database.

Also, we considered that the result of FEM simulation for U-bending in this production part never occurred the crack phenomena. Therefore, it could be well done to the strip process lay out design as showing in Fig. 5.

2.5. Die set selection

There are several kinds of die set model in the die making field regularly. Some time in the particular field, they make special type steel die set for high precision die assembling function. In this study, we considered the automatic roll feeding of strip for the mass production above one hundred thousand of production part and precision production needed, so we selected special type steel die for high precision production part. Also the guide post must be installed within the die block and die shoe size allowance with the high accurate guide bushing fit. It was selected that the die set has six inner guide posts and four outer guide posts for a precision working and high load of pressing. Fig. 7 shows the result of die design that is called press die assembling drawing.

Fig. 7. Die assembling drawing: (a) upper die, (b) front view drawing, and (c) lower die.

3. Die making and tryout

3.1. Die making

The SKD11 high alloy tool steel was selected for punch and die block as a cause of containing of minimized wear among whole of die materials.

Especially, the V1 carbide tool material was selected as a die insert material for the split die components. In this study, we decided the sizes of punch and die block depending on data base, theoretical background and our own field experiences [7]. The machining of punch and die block belongs to the precision machine tool working through the raw material cutting, milling, turning, drilling, profiling,heat treating, electronic discharge machining(EDM,Wire –Cut), jig grinding, especially, CNC machining and mirror machining, etc. Fig. 8 shows the progression of CNC machining center working.

Fig. 8. Progression of CNC machining center working.

Fig. 9 shows the press die making system. Fig. 10 shows the CNC machining center for a representative of die making machine tools.

Fig. 9. Press die making system.

In this study, we used ordinary machine tools, CNC machine tools and EDM, etc. On the accuracy of each fitting component with combination of the following tolerances,the first case is guide bush and guide post tolerance as the H7(hole) h6(shaft) for a slide fitting.

Fig. 10. CNC machining center for die making.

The die set and guide post tolerances are H7(hole)p5(shaft) for a tight fitting. The Punch plate and punch tolerance are H7(hole) m6(shaft) for a tight fitting with a minor interference. The second is stripper and punch tolerances as the H7(hole) h6(shaft) for a slide fitting. The die inserting hole and die inserting button used the H7(hole)m6(shaft) for a minor tight fitting. These fitting tolerances are very careful factors for die making because whole of die setting method must be within fine punch and die activities for the symmetrical equalized clearance to the left and right side each other.

3.2. Try out

Fig. 11 shows the actual strip process layout result from tryout working (200 t power press, 100mm stroke and 40 SPM). In this actual process strip layout, we could confirm the real process for making the production part.

Also we checked the every size of production part with a tolerance control.We could find the jamming problem such as the material strip through the guide tunnel on the die block surface. Also,when the material strip passing through the die tunnel, the roll feeding device

operation was checked very exactly. The trouble shooting of this problem was come from die setting skill and technology.

At this time, the check of die failures was performed through the production part and strip of every stage with punch and die edge by the surveying and measuring with fine instruments.

We considered that all of the failure causes are associated with stress occurring and impact of components in the die components running or its service life, etc..

4. Conclusion

In order to prevent the defect of die design and making,this study developed the practical and adaptive die assembling and components. This study also could be taken optimization from the theoretical back ground, data base and our field experiences and FEM simulation, etc.

The results are as follows:

(1) FEM simulation of strip process layout by DEFORM programming was necessary, not only to the design and its making of the die, but also to the tryout and its revision after the die developing.

(2) The die design was performed as a optimum result with the least defects on the die developing.

(3) The trouble shooting was performed as a successful method of tryout after die making.

(4) For the increasing the utility ratio of material of production part, the scrapless type progressive die became to the optimum design result.

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用于U形零件弯曲加工的中间载体级进模研发过程的研究

摘要

在模具设计中，为U形弯曲板材制作的中间载体级进模是非常特殊的一类。本文重点研究了采用多工位级进模、选用供料切断系统进行的板材成形过程。

通过DEFORM软件进行的有限元分析仿真，我们认为排样工艺布局应该作为U形弯曲的第一步。

模具开发的下一步是根据模具研发的一般规律进行的，其中包括对模具结构，模具加工条件，模具材料，模具的局部热处理等方面的设计，以及对其他部分的设计。

这项研究的最大特点通过I-DEAS软件的建模，实现多工位阶段的无废料级进模设计。并且各类部件都使用Auto-Lisp以及其它的CAD/CAM软件画出，给出了一般的加工工艺，以及提出了在试冲中改进的方法。

关键词：中间载体级进模，有限元仿真，排样工艺布局，U形弯曲加工工艺，无废料级进模，试冲

1.简介

在条料经过模具表面，压力机冲压成形过程中的几个环节中，级进模进行了多项基础性的工作。使用最佳设计的和最佳制造的模具进行冲压加工早已成为了进行大规模成产的加工领域的共同追求。

因此，完成本研究需要完整的冲压工具数据，领域内的实践经验，以及大量的理论计算。要充分兼顾上文提到的一些因素，本设计就需要利用有限元分析，I-DEAS建模和实际的模具加工方法以实现最佳的模具设计。

除此之外，要想产品中能够有尽可能少的缺陷，就需要在试冲中不断的进行改进。

2.模具设计

2.1模具研发系统

图1所示的是模具研发系统的网络图。

图1 模具设计系统网络图

从这个系统的网络图中我们可以看出，模具的产品工程，模具制造技术，标准化，故障诊断，人力资源，采购，工具，材料等等一切都被关联到软件和硬件系统、与此相关的广泛而深刻的技术，以及对应的理论背景。

图2所示的是一种使用现有的Auto-Lisp语言代码在AutoCAD和窗口环境下绘制的模具部件。

图2 利用AUTO-LISP绘制的模具部件

本文中提到的其他的一些模具部件设计均遵循上文提到的设计方法并结合一些经验设计方法。

2.2排样工艺布局

条料展开后，加工工件的位置应是重复摆放在一个连续的区域。

由于上述原因，我们要求条料供料的距离和各个工位在条料的位置要足够的精确。除此之外我们还要求板材的利用率应该尽可能的获得一个精确的排样工艺。要实现这些目标，就必须要通过理论计算和一些实际的工作经验来合理的优化排样工艺布局。

图3所示的是排样工艺布局系统的流程图。为了进行排样工艺布局设计，第一步是要根据要加工部件的数量，需要的加工精度，材料的属性以及材料的厚度来决定进给的方法。设计的第二步是要遵循图3和图4所展示的流程图。从图中我们可以看到产品部件以及用来制作产品的厚金属长度（99mm），金属材料为SPCC，厚度为1.3mm。参照

图4所示的部件图，根据排样工艺布局设计方法，我们就可以设计图5所示的排样工艺设计。在排样设计中我们认为条料宽度，条料的大小，进给量，以及开槽余量都是最合适的数值。

图3排样工艺布局设计系统流程图

图4产品零件图以及展开尺寸:(a)零件尺寸(b)零件展开尺寸

图5排样工艺布局图

整个工艺设计的第一阶段是冲孔，第二阶段是进行导正，第三阶段是开槽，第四阶段再次冲孔，第五阶段作为空工位并进行导正。

第六阶段是进行第一次弯曲处理，第七阶段又一次进行冲孔。

第八阶段是进行第二次弯曲处理。在这些过程中我们必须要注意在各个过程中由于工件错位而造成的破坏和断裂。第九阶段是空工位。第十阶段是校形。第十一阶段是对工件进行切断分离。当这些步骤都进行完之后，整个排样工艺过程结果就如图5所示了。

2.3间隙和配合

经验数据显示，冲压材料的最适宜厚度为1.3mm。

因此，在冲孔以及开槽过程中凸模和凹模边缘之间的间隙应为0.05mm。试用结果显示，此时板材切削边缘的毛刺可以达到最小量。

在U形弯曲时，凸模和凹模边缘的距离，根据数据和经验定为材料厚度的1.1倍。

2.4有限元仿真

图6所示的是用DEFORM程序进行的U形弯曲有限元仿真的结果

图6用DEFORM获得的仿真结果

表1中的数据就是DEFORM程序用于进行有限元仿真的参数。

表1有限元仿真的参数

2.5模架的选择

在模具制造领域通常有几种类型的模架形式。当然，也有一些应用于特殊领域的模架，这类模架往往采用特种钢材制造，而且具有相对较高的精度以实现特殊的功能。在本研究中，我们主要研究采用自动滚动供料的大型条料操作生产，这样生产往往会一次性的生产上百万的产品，这些产品中有高精度的，也有低精度的。对于高精度的模具，我们采用比较特殊的钢材。另外，导柱必须安装在模板和模座的间隙内，这使得高精度的导套能够合适的安装。在高负载的精密冲压中，我们选择选用六个内导柱和四个外导柱进行配合。图7所示的是模具设计的结果，也称为冲压模的装配图。

图7模具的装配图:（a）上模（b）主视图（c）下模

3模具的制造和试冲

3.1模具的制造

由于在众多的模具材料中，SDK11高合金钢具有磨损最小的特点，因此我们选择它作为模板和凸模的材料。