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油档拉深 模具设计

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油档拉深模具设计,油档拉深,模具设计

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卢俊1. 图2-1 零件图工件名称：端盖生产批量：大批量材料：10#钢料厚：2mm设计任务及具体要求1、 结合设计课题进行文献检索，撰写2000字左右的专题综述报告一篇；2、 冲压模图纸设计；3、 冲压模工艺参数计算及设备选型；4、 完成23篇的专业外文资料翻译，字数不得少于5000字；5、 撰写毕业设计说明书8000字以上，学会幻灯片PPT的制作。王志林 题目5：油档拉深模具设计及仿真优化零件名称：油挡 材料：10钢 料厚：1.5mm 设计任务及具体要求1、 结合设计课题进行文献检索，撰写2000字左右的专题综述报告一篇；2、 冲压模图纸设计；3、 冲压模工艺参数计算及设备选型；4、 完成23篇的专业外文资料翻译，字数不得少于5000字；5、 撰写毕业设计说明书8000字以上，学会幻灯片PPT的制作。说明：毕业设计图纸量不少于4张0号图，其中至少有一张为计算机绘图XXXX大学毕业设计说明书题 目: 油档冲压工艺与模具设计 年级、 专业: 姓 名: 学 号: 指 导 教 师: 完 成 时 间: 摘 要随着模具制造的技能化逐步向科学化发展，逐渐由以前手动方式发展为利用软件等高科技方式来辅助设计的完成。冷冲模是其中的一种。毕业设计是在模具专业理论教学之后进行的实践性教学环节。是对所学知识的一次总检验，是走向工作岗位前的一次实战演习。其目的是，综合运用所学课程的理论和实践知识,设计一副完整的模具训练、培养和提高自己的工作能力。巩固和扩充模具专业课程所学内容，掌握模具设计与制造的方法、步骤和相关技术规范。熟练查阅相关技术资料。掌握模具设计与制造的基本技能，如制件工艺性分析、模具工艺方案论证、工艺计算、加工设备选定、制造工艺、收集和查阅设计资料，绘图及编写设计技术文件等。冲压工艺与模具设计应结合工厂的设备、人员等实际情况，从零件的质量、生产效率、生产成本、劳动强度、环境的保护以及生产的安全性各个方面综合考虑，选择技术先进、经济合理、使用安全可靠的工艺方案和模具，以使冲压件的生产在保证达到设计图样上的各项技术要求，尽可能降低冲压的工艺成本和保证安全生产。本文阐述了冲压复合模的结构设计及工作过程，通过工艺分析，采用落料拉深切边工序，通过冲压力、拉深力、顶件力、卸料力等计算，确定模具类型。该模具采用中间导柱圆形模架，左右两边的导柱和导套采用同一型号。落料凹模采用整体结构，废料从凸凹模的开槽中卸出。本模具性能可靠，运行平稳，提高了产品质量和生产效率，降低劳动强度和生产成本。关键词：工艺性分析、模具工艺方案论证、工艺计算、加工设备选定、制造工艺、收集和查阅设计资料，绘图及编写设计技术文件等。目 录摘 要2序 言4第一章、模具工艺分析及工艺方案的确定61.1.冲压成形工艺分析61.1.1.明确设计任务，收集相关资料61.1.2.冲压工艺性分析71.2.冲压工艺方案的制定及模具结构类型7第二章、模具主要工艺设计参数计算82.1.毛坯尺寸和主要参数的计算8第三章、设计前计算123.1.确定排样裁板方式及材料利用率123.1.1.排样方式123.1.2.搭边与料宽123.1.3.裁板方法133.1.4.材料的利用率143.2.确定冲模类型及结构形式143.3.工序压力、压力中心的计算和压力机的选择143.3.1.工序压力的计算143.3.2.冲压力计算143.4.计算模具压力中心163.5.压力机的选择163.6.压力机的校核183.6.1.闭合高度的校核183.6.2.工作台面尺寸的校核183.6.3.滑块行程的校核19第四章、模具主要工作部分尺寸计算204.1模具主要工作部分的设计204.1.1.模具零件设计204.1.2.模架的选用244.2.计算模具主要工作部分的刃口尺寸254.2.1.刃口尺寸的计算原则254.2.2.刃口尺寸的计算及公差的确定264.3.冲裁间隙的调整27第五章、模具总装28设计总结29参考文献30序 言 模具是机械制造中技术先进、影响深远的重要工艺装备,它具有生产效率高、材料利用率高、制件质量优良、工艺适应性好等优点,被广泛应用于汽车、机械、航天、航空、轻工、电子、电器等行业，更是汽车制造的四大工艺之一。模具技术未来发展趋势主要是朝信息化、高速化生产与高精度化发展。因此从设计技术来说，发展重点在于大力推广CAD/CAE/CAM技术的应用，并持续提高效率，特别是板材成型过程的计算机模拟分析技术。模具CAD、CAM技术应向宜人化、集成化、智能化和网络化方向发展，并提高模具CAD、CAM系统专用化程度。 我国冲压模具无论在数量上，还是在质量、技术和能力等方面都已有了很大发展，但与国发经济需求和世界先进水平相比，差距仍很大，一些大型、精度、复杂、长寿命的高档模具每年仍大量进口，特别是中高档轿车的覆盖件模具，目前仍主要依靠进口。一些低档次的简单冲模，已趋供过于求，市场竟争激烈。模具制造技术迅速发展，已成为现代制造技术的重要组成部分。在现代化工业进程中，模具的地位及其重要性越来越被人们所重视，一个国家模具工业技术水平的高低，直接代表着这个国家工业设计制造水平的技术水平，它在很大程度上决定着产品的质量、效益和新产品的开发能力。毕业设计是一种综合性的训练，也是一个重要的专业实训环节，它综合性强，应用知识面宽。随着社会主义市场经济的不断发展，工业产品增多，产品更新换代加快，市场竞争激烈。模具作为一种工具已广泛地应用在各行各业之中。模具是现代化工业生产的重要工艺装备。在国民经济的各个工业部门都越来越多地依靠模具来进行生产加工。模具已成为国民经济的基础工业。模具已成为当代工业的重要手段和工艺发展方向之一。现代工业产品的品种和生产效益的提高，在很大程度上取决于模具的发展和技术经济水平。为了更进一步加强我们的设计能力，巩固所学的专业知识，在毕业之际，特安排了此次的毕业设计。毕业计也是我们专业在学完基础理论课，技术基础课和专业课的基础上，所设置的一个重要的实践性教学环节。本次设计的目的：一、 综合运用本专业所学的理论与生产实际知识，进行一次冲压模设计的实际训练，从而提高我们独立工作能力。二、 巩固复习三年以来所学的各门学科的知识，以致能融贯通，进一步了解从模具设计到模具制造整个工艺流程。三、 掌握模具设计的基本技能，如计算、绘图、查阅设计资料和手册，熟悉标准和规范等。由于本人设计水平有限，经验不足，错误难免，敬请老师批评、指导，不胜感激。第一章、模具工艺分析及工艺方案的确定1.1.冲压成形工艺分析1.1.1.明确设计任务，收集相关资料冲压件的工艺性是指冲压件在冲压加工中的难易程度。所谓冲压工艺性好是指能用普通的冲压方法，在模具寿命和生产率较高、成本较低的条件下得到质量合格的冲压件。因此，冲压件的结构形状、尺寸大小、精度等级、材料及厚度等是否符合冲压的工艺要求，对冲压件质量、模具寿命和生产效率有很大的影响。冲压工艺设计应在研究设计任务，分析设计题目，了解原始数据和工作条件，明确设计内容和要求的条件下，收集调查研究并掌握有关设计设计的原始资料的基础上的基础上进行，做到有目的的设计，避免盲目性。工艺设计的原始资料主要包括如下内容：图1 产品图 （1）冲压件的产品图及技术要求零件图如设计任务书中所示的零件图。技术条件应明确合理。由此可对拉深件的结构，尺寸大小，精度要求以及装配关系，实用性能等有全面了解，以便制定工艺方案，选择模具类型和确定模具精度。 （2）生产类型生产类型是企业生产产业程度的分类，一般分为大量生产、成批生产、小批量生产，该零件的生产类型为大批量生产。 （3）生产组织形式生产类型不相同，零件和产品的组织形式，采用的技术措施和达到的技术经济效果会不同。 （4）工艺装备大批量的的采用专用夹具，标准附件，标准刀具和万能量具，靠划线和试切法达到精度要求。1.1.2.冲压工艺性分析（1）材料：该零件所选材料为10#钢，屈服极限是210MPa，抗拉强度300-440MPa，抗剪强度260-340MPa，具有很好的可冲压性，其具有良好的冲压性能。（2）结构形状：冲裁件内，外形要尽量避免尖锐清角。该工件为凸缘形拉伸件，拉深高度不大，预计一次拉伸能够实现，不过具体拉伸系数需要经过计算得出结果，然后通过翻边实现。1.2.冲压工艺方案的制定及模具结构类型确定工序数量的基本原则是：在保证工件加工质量，生产效率和经效益的前提下，工序数量应尽可能地减少。 该零件精度要求较高，故采用复合模。该零件加工需先落料，然后拉深，然后翻边等3道工序，现考虑实际模具设计数量太多，建议采用复合模，冲压工序中，落料拉伸复合模，所以，本次设计建议选用一副模复合模，一套翻边模来设计。工序少，模具成本低，冲压次数少，冲压成本也降低，比较合理。第二章、模具主要工艺设计参数计算2.1.毛坯尺寸和主要参数的计算从产品形状看，产品有翻边，拉伸等工序，翻边是最后的工序，将翻边部分展开后就是带凸缘的拉伸件，所以计算展开尺寸，必然要先计算凸缘尺寸，然后通过凸缘拉伸件计算公式计算最初的展开尺寸。向外凸的外圆翻边，就变形性质、应力状态来说与不用压边圈的浅拉伸一样，所以翻边展开计算公式可以按拉伸计算公式来计算，无凸缘拉伸计算，翻边之后不需要切边，所以无需查切边余量，直接按8mm计算：零件图如下图所示, 该零件加工需先落料，然后拉深，该零件为典型的无凸缘拉伸件，根据等面积原则采用解析法求毛坯直径。拉伸件毛坯展开尺寸，通常按毛坯面积等于制件面积的原则确定。拉伸件的毛坯尺寸，很难预先精确地计算，这是因为拉伸件壁部在拉伸过程中厚薄程序，随毛坯退火与否、压边力的大小、凸凹模间隙以及变形程度等因素有关。此零件翻边高度低，且没精度要求，所以无需单独查表计算切边余量，所以余量按零计算，此件按无凸缘拉伸的公式计算。计算产品展开尺寸 公式是D=d1.72dr-0.56r+4dH其中：D展开尺寸 d拉伸直径，47-1.5=45.5mm，r拉伸圆角，2+0.75=2.75H拉伸高度，8-0.75=7.25 经过实际计算D=d1.72dr-0.56r+4dH =45.5-1.7245.52.75-0.562.75+445.57.25 =3170.3D=56.3所以翻边之前的凸缘直径为56.3，工序图如下：再次按凸缘拉伸件计算最初的展开尺寸：公式是D=d1.72d(R+r)-0.56(R-r)+4dH其中：D展开尺寸 d凸缘直径，56.3mmd拉伸直径，32-1.5=30.5mmR拉伸圆角，2.5+0.75=3.25r拉伸圆角，2+0.75=2.75H拉伸高度，8-1.5=6.5 经过实际计算D=d1.72d(R+r)-0.56(R-r)+4dH =56.3-1.7230.5(3.25+2.75)-0.56(3.25-2.75)+430.56.5 =3646.25D=60.38展开尺寸还需要经过调试最后确认，本次课题按60.5展开计算。展开图纸如下图所示：图2 展开图拉伸次数的确定判断能否一次拉伸 H/d=6.5/30.5=0.2131 (t/D) 100=2.4793d/d=1.8459 m=d/D=0.504根据以上数据查表得首次拉伸系数m1=0.45，由于m10.504（实际拉伸系数），故能一次拉伸成型，另外根据数据查表，首次拉伸的最大相对高度H1/d1=0.42-0.51，由于0.420.2131，也能说明能一次拉伸成型。第三章、设计前计算3.1.确定排样裁板方式及材料利用率3.1.1.排样方式冲压件在配料上的布置方式称为排样。合理的确定产品的排样方式、坯料形式及尺寸，能够提高产品质量、材料利用率、冲压效率和模具寿命，同时便于冲压操作。 按照材料的利用情况，排样方式分为三种： （1）有废料排样 产品与产品之间、产品与坯料边缘之间均有搭边。 （2）少废料排样 仅在产品与产品（或产品与坯料边缘）之间有搭边 （3）无废料排样 产品与产品之间、产品与坯料边缘之间均无搭边。 根据零件图可以选取少废料排样。这种排样利用率高，用于某些精度要求不是很高的冲裁件排样。 按照产品在坯料上的布置方式分类，排料方式可以分为直排、斜排、多排、对排、混排等。根据零件图可以选取为直排排样。3.1.2.搭边与料宽搭边是指排样时产品与产品之间、产品与坯料之间留下的余料。它可以补偿坯料的定位误差，保证模具具有足够的强度，使条料具有足够的刚度，以便送料。综合考虑材料的力学性能和厚度，及零件的外形尺寸和排样方式，初步选取搭边值为工件间a1=1.0mm，工件侧面a=1.2mm。图3 零件排样图 条料宽度的选取原则：最小条料宽度要能够保证冲裁件周边有足够的搭边值。最大条料宽度要保证冲裁时在导料板之间顺利送行并与导料板之间有一定的间隙。条料在模具上每次送进的距离称为送料步距（简称为步距或进距）其大小为条料上两个对应冲裁件的对应点之间的距离。条料宽度 b=D+2a=60.5mm+21.2mm=62.9mm送料步距 s=D+a=60.5mm+1.0mm=61.5mm3.1.3.裁板方法 板材规格选用1.5mm1250mm3000mm 设每张钢板裁板条数为n，为了操作方便采取横裁： n=3000/62.9=47条，余43.7mm 每条裁板上的工件数为n，得： n=（B-a）%S =（1250-1.0）/61.5=20个，余20mm 每张钢板上的工件总数 n=4720=940个 B钢板宽度1250mm3.1.4.材料的利用率材料的利用率是指产品的实际面积与所用坯料面积的百分比，即： K=F/ F100% =(n)/(4LB)100% =(9403.1460.5）/(430001250)100% =72.023% K 材料利用率 ； F 产品的实际面积（mm2）； F 坯料面积（mm2）； L 钢板长度 3000mm；3.2.确定冲模类型及结构形式冲压工艺性分析之后拟定冲压工艺方案时选择复合模，因为零件的几何形状简单对称，所以复合模结构相对简单，操作方便，能够直接利用压力机的打杆装置进行推件，卸件可靠方便，模具类型为少废料落料拉深切边复合模。3.3.工序压力、压力中心的计算和压力机的选择3.3.1.工序压力的计算已知工件的材料为纯钼，其力学性能如下：=260340Mpa, =300-440Mpa, =240Mpa。（查4表1-1）3.3.2.冲压力计算在冲压模具设计时，冲压力是指落料力、卸料力、拉深力、压边力、切边力、推件力和顶件力的总称。它是冲压时选择压力机，进行模具设计时校核强度和刚度的重要依据。对于落料拉伸模（1）落料力的计算 KLt =1.3Dt =1.33.1460.51.5340N =125950.11N 125.95KN 落料力（KN)； K 安全系数，一般可取K=1.3； L 冲裁轮廓周长（mm）； T 料厚（mm）； 材料的抗剪强度（Mpa）； （2）卸料力的计算 = =0.04125.95KN 5.038KN 卸料力（N）； 卸料力系数（查1表3-11）； F 冲裁力（N)； （3）拉深力的计算 = =3.14321.54401N =66316.8N 66.317KN 拉深力（N)； 首次拉深修正系数（查1表5-10）； 材料抗拉强度（Mpa）； （4）压边力的计算 圆筒形件第一次拉深时压边力 =p =60.5-（32+22）2.5N =4639.84N 4.64KN 首次拉深凹模圆角半径； P 单位压边力（查1表5-9）； 第一次拉深时的压边力（N)；（5）翻边力的计算 翻边力也按拉伸公式计算： = =3.14471.54401N =97402.8N 97.4KN 拉深力（N)； 首次拉深修正系数（查1表5-10）； 材料抗拉强度（Mpa）；所以落料拉伸模总冲压力为F=125.95+5.038+66.317+4.64=201.945KN。所以翻边模总冲压力为F=97.4KN。3.4.计算模具压力中心冲压力合理的作用点称为模具的压力中心。模具的压力中心应该通过压力机滑块的中心线。对于有曲柄的冲模来说，虚实压力中心通过曲柄的中心线。以便于冲模平稳工作，减少导向件的磨损，从而提高模具的寿命。由于该工件的毛坯和各工序工件均为轴对称图形，而且只有一个工位，因此压力机的中心必定与制件的几何中心重合，所以模具的压力中心就在圆心部位，无需再次计算。3.5.压力机的选择压力机的公称压力必须大于或等于冲压力。计算总冲压力原则上只计算同时发生的力。拉深力出现在落料力之后，因此最大冲压力出现在冲裁阶段，模具采用弹性卸料装置和上出料方式。对于浅拉伸，落料，冲孔、切边等施力行程较小的冲压工序，可以直接选用公称压力大于所需冲压力总和的压力机，对于深拉深、深弯曲等施力行程较大的冲压工序，应按所需工艺力小于或等于压力机公称压力50%60%的条件选取压力机。从满足冲压力要求看，落料拉伸可以初选400KN规格的压力机 JC2340（查2表3-1），其主要技术参数为： 公称压力： 400KN 滑块行程： 100mm 最大封闭高度： 300mm 封闭高度调节量： 80mm 工作台尺寸： 300mm450mm 工作台垫板尺寸： 80mm200mm 模柄孔尺寸： 50mm70 mm 垫板厚度： 80mm 最大倾斜角： 30 电动机功率： 4.0KW从满足冲压力要求看，翻边模可以初选160KN规格的压力机 JC2316 （查2表3-1），其主要技术参数为： 公称压力： 160KN 滑块行程： 50mm 最大封闭高度： 220mm 封闭高度调节量： 45mm 工作台尺寸： 300mm450mm 工作台垫板尺寸： 40mm210mm 模柄孔尺寸： 40mm60 mm 垫板厚度： 40mm 最大倾斜角： 30 电动机功率： 1.5KW3.6.压力机的校核3.6.1.闭合高度的校核落料拉伸模所选压力机的最大闭合高度为300mm，闭合高度调节量为80mm，垫板高度为40mm，所以： 300mm-80mm=220mm本次设计模具，落料拉伸模见CAD图纸，闭合高度为H=200mm， 5mm=295mm 230mm如果模具高度满足H5，即能满足要求，本次设计的模具，闭合高度不能满足要求，需要增加等高铁。翻边模所选压力机的最大闭合高度为220mm，闭合高度调节量为45mm，垫板高度为40mm，所以： 220mm-45mm=175mm本次设计模具，翻边模见CAD图纸，闭合高度为H=177.5mm， 5mm=215mm 185mm如果模具高度满足H5，即能满足要求，本次设计的模具，闭合高度不能满足要求，需要增加等高铁。3.6.2.工作台面尺寸的校核落料拉伸模，所选压力机工作台尺寸为 ：前后300mm，左右450mm ，模具外形尺寸为D=160mm，选择9#中间导柱圆形标准模架，模具底座外形尺寸为：前后340mm，左右230mm，根据工作台面尺寸一般应大于模具底座尺寸5070mm，其工作台孔径尺寸为D=210mm，大于废料尺寸，可以漏料，所以工作台尺寸满足要求。翻边模，所选压力机工作台尺寸为 ：前后300mm，左右450mm ，模具外形尺寸为D=140mm，选择18#后侧导柱标准模架，模具底座外形尺寸为：前后205mm，左右250mm，根据工作台面尺寸一般应大于模具底座尺寸5070mm，其工作台孔径尺寸为D=210mm，大于废料尺寸，可以漏料，所以工作台尺寸满足要求。3.6.3.滑块行程的校核滑块行程应保证能够方便地放入毛坯和取出零件，对于拉深工序，滑块行程应大于零件高度的2倍，零件高度2=8mm2=16mm，所选压力机的滑块行程为50mm，所以滑块行程满足要求。第四章、模具主要工作部分尺寸计算4.1模具主要工作部分的设计本设计采用落料拉深复合模，翻边工序，两幅模具。4.1.1.模具零件设计首先要考虑凹凸模的壁厚是否过薄，本次设计凹凸模的最小壁厚查表（查1表3-16）为14.2mm，满足最小壁厚a1.2t=1.8mm的要求，能够保证强度，所以采用复合模。（1）落料凹模高度的确定落料凹模高度为H=KS （8mm） =（0.3660.5）mm=21.78mmS垂直于送料方向的凹模刃壁件最大距离（mm）；K凹模厚度系数，考虑板料厚度的影响得凹模孔壁至凹模边缘的最小距离=2S=43.56mm 送料方向的凹模长度 L=（60.5+243.56)mm=147.62mm根据 GB2858.481，并考虑总体布局，选择圆形凹模板，尺寸为D =160mm，刃口高度选择40mm，材料采用Cr12MoV，工作部分热处理硬度为6064HRC，结构图如下：图4 落料凹模 送料方向的凹模刃壁间最大距离（mm)； 送料方向的凹模孔壁至凹模边缘的最小距离（mm)； （2）依据凹模尺寸，查国标GB2858.681，选择圆形垫板尺寸为DH=160mm8mm，材料为45钢， 热处理硬度4348HRC。（3）卸料装置的设计卸料装置采用弹性卸料装置，以方便卸料，由于卸件力较小。卸料板内孔每侧与凸模保持间隙距离0.15mm，卸料板周界尺寸与凹模周界尺寸一样，厚度根据冲裁件料厚和导料板厚度取15mm，选择圆形导料板，其尺寸为DH=160mm15mm，导料板采用45钢制造，淬火硬度为4348HRC。结构简图如下：图5 卸料板 （4）固定板设计凸模的固定方式有直接固定在模座、用固定板固定和快换式固定三种固定方式，这里选用固定板固定，固定板与凸模为过渡配合（H7/n6），根据GB2858.581及凹模尺寸选取凸模固定板尺寸DH=160mm18mm。同理，选择凹凸模固定板尺寸为DH=160mm18mm。（5）为了防止拉深时起皱，需用压边圈，压边圈与凸模的单面间隙选为0.2mm，与凹模的单边间隙取0.2mm，压边圈采用Cr12MoV钢制造，热处理硬度为5558HRC，高度选为32.5mm。（6）凸凹模设计结合工件外形并考虑加工，将凸凹模设计成带肩台阶式圆凸凹模，一方面加工简单，另一方面又便于装配与更换，采用车床加工，与凸凹模固定板的配合按H7/m6，材料采用Cr12MoV，工作部分热处理淬硬6064HRC，其高度为： L= =36mm+18mm =54mm，本次设计取55。 弹簧安装高度； 凹凸模工作高度；结构图如下：图7 凹凸模（7）翻边凹模的设计，选用Cr12MoV钢制造，热处理硬度为5558HRC，高度选为38mm。（8）翻边凸模的设计，选用Cr12MoV钢制造，热处理硬度为5558HRC，外圆与固定板过盈配合。（9）模柄的设计模柄选择压入式模柄，材料选用Q235，热处理硬度4348HRC，依据模具设计尺寸，参考GB2862.190，选用B型。4.1.2.模架的选用模具的闭合高度是指模具在最低工作位置时上下模座之间的距离，它应与压力机的装模高度相适应，从生产量、模具结构、产品规格和操作方便等方面考虑。 落料拉伸模选择9#中间导柱圆形，查GB/T 2851.690，所选模架具体参数如下：凹模周界：160mm闭合高度(参考)最小：160mm闭合高度(参考)最大：210mm上模座 数量1 规格：340mm230mm35mm下模座 数量1 规格：340mm230mm40mm导柱 数量2 规格：28mm180mm，32mm180mm，导套 数量2 规格：28mm140mm42mm，32mm140mm45mm 翻边模选择18后侧导柱标准模架，查GB/T 2851.690，所选模架具体参数如下：凹模周界：140mm闭合高度(参考)最小：159mm闭合高度(参考)最大：185mm上模座 数量1 规格：250mm205mm30mm下模座 数量1 规格：250mm205mm35mm导柱 数量2 规格：25mm150mm导套 数量2 规格：25mm140mm35mm 导柱与导套结构从标准中选取，尺寸由模架中的参数决定。导柱的长度应保证冲模在最低工作位置时，导柱上端面与上模座顶面的距离不小于1015mm，而下模座底面与导柱底面的距离应为12mm。导柱与导套之间的配合为H7/h6,导套与上模座之间、导柱与下模座之间采用过渡配合H7/m6。导柱与导套材料采用20钢，热处理硬度为（渗碳）5662HRC。上下模座材料采用20#钢，热处理硬度为调质2832HRC。4.2.计算模具主要工作部分的刃口尺寸4.2.1.刃口尺寸的计算原则 （1）刃口尺寸应保证能冲出合格工件由于落料件的实际尺寸基本与凹模刃口尺寸一致，设计落料模，切边模时应以凹模尺寸为基准。因此，落料模，切边模应先决定凹模的尺寸，间隙取在凸模上，用减小凸模尺寸来保证合理的间隙。冲孔模的尺寸取决于凸模，因此，冲孔模应先决定凸模尺寸。间隙取在凹模上，用增大凹模尺寸来保证合理的间隙。 （2)刃口磨损一些仍能冲出合格件考虑刃口的磨损对冲件尺寸的影响。刃口磨损后尺寸变大，设计模具时其刃口的基本尺寸应接近或等于冲件的最小极限尺寸；刃口磨损后尺寸变小，设计模具时其刃口基本尺寸应接近或等于冲件的最大极限尺寸。 （3）设计模具时应取最小合理冲裁间隙 随着凸模与凹模磨损量的不断增大，冲裁间隙也会不断增大。所以模具设计时冲裁间隙应取其允许的最小值。 （4）考虑冲件精度与模具精度之间的关系，选择模具制造公差时，既要保证冲件的精度要求又要保证有合理的间隙值。一般冲模精度较冲件精度高23级。采用分别制造法制造凹凸模。4.2.2.刃口尺寸的计算及公差的确定（1）落料刃口尺寸的计算： =（60.6-0.50.2）mm =60.5mm =（60.5-0.1）mm =60.4mm 、分别为落料凹、凸模刃口尺寸； D落料件外径的最大极限尺寸； 冲裁件制造公差； X磨损系数，其值在0.51之间，与冲裁件精度等级有关； 最小初始双面间隙；0.1 、分别为凹、凸模的制造公差，取=0.6（） =0.4()； （2） 拉深部分凹凸模尺寸的计算： =（32.1-0.50.2）mm =32mm （32-1.5-1.5)mm =29mm 其中，拉深模的圆角半径=2.5mm，=2mm； 、 分别为拉伸凹、凸模尺寸； 拉深件制造公差； Z凹凸模间隙，Z=(22.2）t，取Z=2.0t； X磨损系数，其值在0.51之间，与冲裁件的精度等级有关； 、别为拉深凹、凸模的圆角半径；（3）翻边部分凹凸模尺寸的计算：具体计算如下，制件标注外形尺寸，按此公式计算凹模尺寸为Ld=（Lmax0.5）=47凸模尺寸为Lp=（Ld0.5Z）=47-1.5-1.5=44凸、凹模工作表面粗造度要求：凹模工作表面和型腔表面粗造度应达到0.8；圆角处的表面粗造度一般要求0.4；凸模工作部分表面粗造度一般要求0.8-1.6。 查8表3-2得，落料凹模制造公差等级选择IT8级，凸模制造公差等级选择IT7级。4.3.冲裁间隙的调整对于冲裁模，即便模具零件的加工精度已经得到保证，但是在装配时，如不能保护冲裁间隙仍然会影响制件的质量和模具的使用寿命。第五章、模具总装 （1）把组装上了凸模的固定板放在下模座上，按中心线打正固定板的位置，用平行夹头夹紧，通过螺钉孔在下模座上钻出锥窝，拆去凸模固定板，在下模座上按锥窝钻螺纹底孔并攻丝，重新将凸模固定板置于下模座上并找正，用螺钉紧固，钻孔，打入销钉定位。 （2）配钻卸料螺钉孔时，将卸料板套在已装入固定板的凹凸模上，在固定板与卸料板之间垫上适当高度的等高垫铁，并用平行夹头将其夹紧，按卸料板上螺孔位置在模座上钻锥窝，然后拆开，按锥窝钻孔。 （3）在凹凸模固定板的弹簧孔中装入卸料弹簧，将卸料板套入凹凸模；用（1）中同样的方法配钻垫板和上模座上的螺钉孔，推杆孔，然后依次将垫片和卸料板、凹凸模、凹凸模固定板的组合部件装入上模座，用紧固螺钉固定，打入销钉定位。 （4）在落料凹模上装入挡料销，将推件块装入落料凹模，并将推杆装入固定板上的推杆孔，用紧固螺钉将落料凹模与凸模固定板固定，钻孔，打入销钉定位。设计总结 通过本次毕业设计我熟悉了冲压模具的整个设计过程，掌握了冷冲压模具设计的方法和步骤，了解了在做冲压模具之前首先要对产品的结构形态，模具的结构形态以及产品的工艺性进行合理的分析，才能设计出更合适模具，节约成本的同时还能保证加工零件的精度要求。其次，考虑好产品的批量以及精度要求以及材料的造价；最后完成产品的模具设计、模具的装配图、零件图。掌握了冷冲压模具设计的基本技能，如计算，绘图，查阅设计资料和手册，熟悉标准和规范等，通过本次毕业设计，使自己各方面知识都有所提高。与此同时，也思考了以后的工作心态和生活态度。我们即将离开校园、投入到工作中，不知的困难和自己的奋斗目标总是在激励自己不放弃，勇敢向前，通过设计中发现的问题、也给自己敲响了警钟、事物每天都会有变化、一成不变只会让历史的车轮碾得粉碎。为了未来的精彩、加油加油、不屈不挠才会有突破、毕业了、也是一个新的开始、奋斗的日子开始了、每天都会很精彩、加油！ 参考文献1、 陈剑鹤 吴云飞模具设计基础.机械工业出版社200932、 朱江峰 闫志波冲压成型工艺与模具设计华中科技大学出版社201263、 虞建中模具制造工艺人民邮电出版社200844、 杨櫂 陈国香机械制造与模具制造工艺学清华大学出版社200655、 翁其金 徐新成冲压工艺与冲模设计机械工业出版社2004.7，2011年6月第1版6、 付宏生冷冲压成形工艺与模具设计制造化学工业出版社，2005.3,2005年3月第1版7、 钟玉斌冲压工艺与模具设计机械工业出版社，2000.5，2000年5月第1版8、 阳勇冷冲压工艺与模具设计北京理工大学出版社，2010.8,2010年8月第1版9、 韩英淳简明冲模设计手册上海科学技术出版社，2006.11,2006年11月第1版10、蒙以嫦 梁艳娟冲压模具设计与制造北京理工大学出版社，2010.4,2010年4月第1版11、吴伯杰冲压工艺与模具电子工业出版社，2004.6,2004年7月第1版12、韩进宏互换性与技术测量机械工业出版社，2007.7，2011年1月第1版13、刘朝儒 吴志军机械制图高等教育出版社，2006.12,2006年12月第5版第 30 页 共 30 页Int J Adv Manuf Technol (2002) 19:253259 2002 Springer-Verlag London LimitedAn Analysis of Draw-Wall Wrinkling in a Stamping Die DesignF.-K. Chen and Y.-C. LiaoDepartment of Mechanical Engineering, National Taiwan University, Taipei, TaiwanWrinkling that occurs in the stamping of tapered square cupsand stepped rectangular cups is investigated. A commoncharacteristic of these two types of wrinkling is that thewrinkles are found at the draw wall that is relatively unsup-ported. In the stamping of a tapered square cup, the effect ofprocess parameters, such as the die gap and blank-holderforce, on the occurrence of wrinkling is examined using finite-element simulations. The simulation results show that the largerthe die gap, the more severe is the wrinkling, and suchwrinkling cannot be suppressed by increasing the blank-holderforce. In the analysis of wrinkling that occurred in the stampingof a stepped rectangular cup, an actual production part thathas a similar type of geometry was examined. The wrinklesfound at the draw wall are attributed to the unbalancedstretching of the sheet metal between the punch head and thestep edge. An optimum die design for the purpose of eliminatingthe wrinkles is determined using finite-element analysis. Thegood agreement between the simulation results and thoseobserved in the wrinkle-free production part validates theaccuracy of the finite-element analysis, and demonstrates theadvantage of using finite-element analysis for stamping diedesign.Keywords: Draw-wall wrinkle; Stamping die; Stepped rec-tangular cup; Tapered square cups1.IntroductionWrinkling is one of the major defects that occur in the sheetmetal forming process. For both functional and visual reasons,wrinkles are usually not acceptable in a finished part. Thereare three types of wrinkle which frequently occur in the sheetmetal forming process: flange wrinkling, wall wrinkling, andelastic buckling of the undeformed area owing to residualelastic compressive stresses. In the forming operation of stamp-ing a complex shape, draw-wall wrinkling means the occurrenceCorrespondence and offprint requests to: Professor F.-K. Chen, Depart-ment of Mechanical Engineering, National Taiwan University, No. 1Roosevelt Road, Sec. 4, Taipei, Taiwan 10617. E-mail: fkchen?.twof wrinkles in the die cavity. Since the sheet metal in the wallarea is relatively unsupported by the tool, the elimination ofwall wrinkles is more difficult than the suppression of flangewrinkles. It is well known that additional stretching of thematerial in the unsupported wall area may prevent wrinkling,and this can be achieved in practice by increasing the blank-holder force; but the application of excessive tensile stressesleads to failure by tearing. Hence, the blank-holder force mustlie within a narrow range, above that necessary to suppresswrinkles on the one hand, and below that which producesfracture on the other. This narrow range of blank-holder forceis difficult to determine. For wrinkles occurring in the centralarea of a stamped part with a complex shape, a workablerange of blank-holder force does not even exist.In order to examine the mechanics of the formation ofwrinkles, Yoshida et al. 1 developed a test in which a thinplate was non-uniformly stretched along one of its diagonals.They also proposed an approximate theoretical model in whichthe onset of wrinkling is due to elastic buckling resulting fromthe compressive lateral stresses developed in the non-uniformstress field. Yu et al. 2,3 investigated the wrinkling problemboth experimentally and analytically. They found that wrinklingcould occur having two circumferential waves according totheir theoretical analysis, whereas the experimental results indi-cated four to six wrinkles. Narayanasamy and Sowerby 4examined the wrinkling of sheet metal when drawing it througha conical die using flat-bottomed and hemispherical-endedpunches. They also attempted to rank the properties thatappeared to suppress wrinkling.These efforts are focused on the wrinkling problems associa-ted with the forming operations of simple shapes only, suchas a circular cup. In the early 1990s, the successful applicationof the 3D dynamic/explicit finite-element method to the sheet-metal forming process made it possible to analyse the wrinklingproblem involved in stamping complex shapes. In the presentstudy, the 3D finite-element method was employed to analysethe effects of the process parameters on the metal flow causingwrinkles at the draw wall in the stamping of a tapered squarecup, and of a stepped rectangular part.A tapered square cup, as shown in Fig. 1(a), has an inclineddraw wall on each side of the cup, similar to that existing ina conical cup. During the stamping process, the sheet metalon the draw wall is relatively unsupported, and is therefore254F.-K. Chen and Y.-C. LiaoFig. 1. Sketches of (a) a tapered square cup and (b) a steppedrectangular ne to wrinkling. In the present study, the effect of variousprocess parameters on the wrinkling was investigated. In thecase of a stepped rectangular part, as shown in Fig. 1(b),another type of wrinkling is observed. In order to estimate theeffectiveness of the analysis, an actual production part withstepped geometry was examined in the present study. Thecause of the wrinkling was determined using finite-elementanalysis, and an optimum die design was proposed to eliminatethe wrinkles. The die design obtained from finite-element analy-sis was validated by observations on an actual production part.2.Finite-Element ModelThe tooling geometry, including the punch, die and blank-holder,weredesignedusingtheCADprogramPRO/ENGINEER. Both the 3-node and 4-node shell elements wereadopted to generate the mesh systems for the above toolingusing the same CAD program. For the finite-element simul-ation, the tooling is considered to be rigid, and the correspond-ing meshes are used only to define the tooling geometry andFig. 2. Finite-element mesh.are not for stress analysis. The same CAD program using 4-node shell elements was employed to construct the meshsystem for the sheet blank. Figure 2 shows the mesh systemfor the complete set of tooling and the sheet-blank used in thestamping of a tapered square cup. Owing to the symmetricconditions, only a quarter of the square cup is analysed. Inthe simulation, the sheet blank is put on the blank-holder andthe die is moved down to clamp the sheet blank against theblank-holder. The punch is then moved up to draw the sheetmetal into the die cavity.In order to perform an accurate finite-element analysis, theactual stressstrain relationship of the sheet metal is requiredas part of the input data. In the present study, sheet metalwith deep-drawing quality is used in the simulations. A tensiletest has been conducted for the specimens cut along planescoinciding with the rolling direction (0) and at angles of 45and 90 to the rolling direction. The average flow stress ?,calculated from the equation ? ? (?0? 2?45? ?90)/4, for eachmeasured true strain, as shown in Fig. 3, is used for thesimulations for the stampings of the tapered square cup andalso for the stepped rectangular cup.All the simulations performed in the present study were runon an SGI Indigo 2 workstation using the finite-element pro-gram PAMFSTAMP. To complete the set of input data requiredFig. 3. The stressstrain relationship for the sheet metal.Draw-Wall Wrinkling in a Stamping Die Design255for the simulations, the punch speed is set to 10 m s?1and acoefficient of Coulomb friction equal to 0.1 is assumed.3.Wrinkling in a Tapered Square CupA sketch indicating some relevant dimensions of the taperedsquare cup is shown in Fig. 1(a). As seen in Fig. 1(a), thelength of each side of the square punch head (2Wp), the diecavity opening (2Wd), and the drawing height (H) are con-sidered as the crucial dimensions that affect the wrinkling.Half of the difference between the dimensions of the die cavityopening and the punch head is termed the die gap (G) in thepresent study, i.e. G ? Wd? Wp. The extent of the relativelyunsupported sheet metal at the draw wall is presumably dueto the die gap, and the wrinkles are supposed to be suppressedby increasing the blank-holder force. The effects of both thedie gap and the blank-holder force in relation to the occurrenceof wrinkling in the stamping of a tapered square cup areinvestigated in the following sections.3.1Effect of Die GapIn order to examine the effect of die gap on the wrinkling,the stamping of a tapered square cup with three different diegaps of 20 mm, 30 mm, and 50 mm was simulated. In eachsimulation, the die cavity opening is fixed at 200 mm, and thecup is drawn to the same height of 100 mm. The sheet metalused in all three simulations is a 380 mm ? 380 mm squaresheet with thickness of 0.7 mm, the stressstrain curve for thematerial is shown in Fig. 3.The simulation results show that wrinkling occurred in allthree tapered square cups, and the simulated shape of thedrawn cup for a die gap of 50 mm is shown in Fig. 4. It isseen in Fig. 4 that the wrinkling is distributed on the drawwall and is particularly obvious at the corner between adjacentwalls. It is suggested that the wrinkling is due to the largeunsupported area at the draw wall during the stamping process,also, the side length of the punch head and the die cavityFig. 4. Wrinkling in a tapered square cup (G ? 50 mm).opening are different owing to the die gap. The sheet metalstretched between the punch head and the die cavity shoulderbecomes unstable owing to the presence of compressive trans-verse stresses. The unconstrained stretching of the sheet metalunder compression seems to be the main cause for the wrink-ling at the draw wall. In order to compare the results for thethree different die gaps, the ratio ? of the two principal strainsis introduced, ? being ?min/?max, where ?maxand ?minare themajor and the minor principal strains, respectively. Hosfordand Caddell 5 have shown that if the absolute value of ? isgreater than a critical value, wrinkling is supposed to occur,and the larger the absolute value of ?, the greater is thepossibility of wrinkling.The ? values along the cross-section MN at the samedrawing height for the three simulated shapes with differentdie gaps, as marked in Fig. 4, are plotted in Fig. 5. It is notedfrom Fig. 5 that severe wrinkles are located close to the cornerand fewer wrinkles occur in the middle of the draw wall forall three different die gaps. It is also noted that the bigger thedie gap, the larger is the absolute value of ?. Consequently,increasing the die gap will increase the possibility of wrinklingoccurring at the draw wall of the tapered square cup.3.2Effect of the Blank-Holder ForceIt is well known that increasing the blank-holder force canhelp to eliminate wrinkling in the stamping process. In orderto study the effectiveness of increased blank-holder force, thestamping of a tapered square cup with die gap of 50 mm,which is associated with severe wrinkling as stated above, wassimulated with different values of blank-holder force. Theblank-holder force was increased from 100 kN to 600 kN,which yielded a blank-holder pressure of 0.33 MPa and 1.98MPa, respectively. The remaining simulation conditions aremaintained the same as those specified in the previous section.An intermediate blank-holder force of 300 kN was also usedin the simulation.The simulation results show that an increase in the blank-holder force does not help to eliminate the wrinkling thatoccurs at the draw wall. The ? values along the cross-sectionFig. 5. ?-value along the cross-section MN for different die gaps.256F.-K. Chen and Y.-C. LiaoMN, as marked in Fig. 4, are compared with one another forthe stamping processes with blank-holder force of 100 kN and600 kN. The simulation results indicate that the ? values alongthe cross-section MN are almost identical in both cases. Inorder to examine the difference of the wrinkle shape for thetwo different blank-holder forces, five cross-sections of thedraw wall at different heights from the bottom to the line MN, as marked in Fig. 4, are plotted in Fig. 6 for both cases.It is noted from Fig. 6 that the waviness of the cross-sectionsfor both cases is similar. This indicates that the blank-holderforce does not affect the occurrence of wrinkling in the stamp-ing of a tapered square cup, because the formation of wrinklesis mainly due to the large unsupported area at the draw wallwhere large compressive transverse stresses exist. The blank-holder force has no influence on the instability mode of thematerial between the punch head and the die cavity shoulder.4.Stepped Rectangular CupIn the stamping of a stepped rectangular cup, wrinkling occursat the draw wall even though the die gaps are not so significant.Figure 1(b) shows a sketch of a punch shape used for stampinga stepped rectangular cup in which the draw wall C is followedby a step DE. An actual production part that has this typeof geometry was examined in the present study. The materialused for this production part was 0.7 mm thick, and the stressstrain relation obtained from tensile tests is shown in Fig. 3.The procedure in the press shop for the production of thisstamping part consists of deep drawing followed by trimming.In the deep drawing process, no draw bead is employed onthe die surface to facilitate the metal flow. However, owingto the small punch corner radius and complex geometry, asplit occurred at the top edge of the punch and wrinkles werefound to occur at the draw wall of the actual production part,as shown in Fig. 7. It is seen from Fig. 7 that wrinkles aredistributed on the draw wall, but are more severe at the corneredges of the step, as marked by AD and BE in Fig. 1(b).The metal is torn apart along the whole top edge of the punch,as shown in Fig. 7, to form a split.In order to provide a further understanding of the defor-mation of the sheet-blank during the stamping process, a finite-element analysis was conducted. The finite-element simulationwas first performed for the original design. The simulatedshape of the part is shown from Fig. 8. It is noted from Fig.8 that the mesh at the top edge of the part is stretchedFig. 6. Cross-section lines at different heights of the draw wall fordifferent blank-holder forces. (a) 100 kN. (b) 600 kN.Fig. 7. Split and wrinkles in the production part.Fig. 8. Simulated shape for the production part with split and wrinkles.significantly, and that wrinkles are distributed at the draw wall,similar to those observed in the actual part.The small punch radius, such as the radius along the edgeAB, and the radius of the punch corner A, as marked in Fig.1(b), are considered to be the major reasons for the wallbreakage. However, according to the results of the finite-element analysis, splitting can be avoided by increasing theabove-mentioned radii. This concept was validated by theactual production part manufactured with larger corner radii.Several attempts were also made to eliminate the wrinkling.First, the blank-holder force was increased to twice the originalvalue. However, just as for the results obtained in the previoussection for the drawing of tapered square cup, the effect ofblank-holder force on the elimination of wrinkling was notfound to be significant. The same results are also obtained byincreasing the friction or increasing the blank size. We concludethat this kind of wrinkling cannot be suppressed by increasingthe stretching force.Since wrinkles are formed because of excessive metal flowin certain regions, where the sheet is subjected to large com-pressive stresses, a straightforward method of eliminating thewrinkles is to add drawbars in the wrinkled area to absorb theredundant material. The drawbars should be added parallel tothe direction of the wrinkles so that the redundant metal canbe absorbed effectively. Based on this concept, two drawbarsare added to the adjacent walls, as shown in Fig. 9, to absorbthe excessive material. The simulation results show that theDraw-Wall Wrinkling in a Stamping Die Design257Fig. 9. Drawbars added to the draw walls.wrinkles at the corner of the step are absorbed by the drawbarsas expected, however some wrinkles still appear at the remain-ing wall. This indicates the need to put more drawbars at thedraw wall to absorb all the excess material. This is, however,not permissible from considerations of the part design.One of the advantages of using finite-element analysis forthe stamping process is that the deformed shape of the sheetblank can be monitored throughout the stamping process, whichis not possible in the actual production process. A close lookat the metal flow during the stamping process reveals that thesheet blank is first drawn into the die cavity by the punchhead and the wrinkles are not formed until the sheet blanktouches the step edge DE marked in Fig. 1(b). The wrinkledshape is shown in Fig. 10. This provides valuable informationfor a possible modification of die design.An initial surmise for the cause of the occurrence of wrink-ling is the uneven stretch of the sheet metal between the punchcorner radius A and the step corner radius D, as indicated inFig. 1(b). Therefore a modification of die design was carriedout in which the step corner was cut off, as shown in Fig.11, so that the stretch condition is changed favourably, whichallows more stretch to be applied by increasing the step edges.However, wrinkles were still found at the draw wall of thecup. This result implies that wrinkles are introduced becauseof the uneven stretch between the whole punch head edge andthe whole step edge, not merely between the punch corner andFig. 10. Wrinkle formed when the sheet blank touches the steppededge.Fig. 11. Cut-off of the stepped corner.the step corner. In order to verify this idea, two modificationsof the die design were suggested: one is to cut the whole stepoff, and the other is to add one more drawing operation, thatis, to draw the desired shape using two drawing operations.The simulated shape for the former method is shown in Fig.12. Since the lower step is cut off, the drawing process isquite similar to that of a rectangular cup drawing, as shown inFig. 12. It is seen in Fig. 12 that the wrinkles were eliminated.In the two-operation drawing process, the sheet blank wasfirst drawn to the deeper step, as shown in Fig. 13(a). Sub-sequently, the lower step was formed in the second drawingoperation, and the desired shape was then obtained, as shownin Fig. 13(b). It is seen clearly in Fig. 13(b) that the steppedrectangular cup can be manufactured without wrinkling, by atwo-operation drawing process. It should also be noted that inthe two-operation drawing process, if an opposite sequence isapplied, that is, the lower step is formed first and is followedby the drawing of the deeper step, the edge of the deeper step,as shown by AB in Fig. 1(b), is prone to tearing because themetal cannot easily flow over the lower step into the die cavity.The finite-element simulations have indicated that the diedesign for stamping the desired stepped rectangular cup usingone single draw operation is barely achieved. However, themanufacturing cost is expected to be much higher for the two-operation drawing process owing to the additional die cost andoperation cost. In order to maintain a lower manufacturingcost, the part design engineer made suitable shape changes,and modified the die design according to the finite-elementFig. 12. Simulated shape for the modified die design.258F.-K. Chen and Y.-C. LiaoFig. 13. (a) First operation and (b) second operation in the two-operation drawing process.simulation result to cut off the lower step, as shown in Fig.12. With the modified die design, the actual stamping die forproduction was manufactured and the production part wasfound to be free from wrinkles, as shown in Fig. 14. The partshape also agreed well with that obtained from the finite-element simulation.In order to fu