外缘翻边圆孔板的落料冲孔复合模具设计【说明书+CAD】
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邵 阳 学 院毕业设计(论文)开题报告书课 题 名 称 外缘翻边圆孔板的设计 学 生 姓 名 温 迎 春 学 号 0231120088 院(系)、专 业 机械工程学院模具设计与制造指 导 老 师 曾 周 亮 2005 年 3 月 25 日一、课题的来源、目的意义(包括应用前景)、国内外现状及水平随着社会主义市场经济的不断发展,城市化进程加快,人们生活水平不断提高,工业产品品种增多,产品更新换代加快,市场竞争日益激烈,势必会引起冲裁模具技术的改进和革新。 模具制造技术是随着现代工业建设而发展的。因此,要想占有市场,首先要拥有先进的模具技术。近年来模具技术发展很快,在国内模具工业产值中所占的比例不断扩大。特别是家用电器所需的塑料模具基本上可立足于国内生产。我国模具有了长足的进步,特别体现在高新技术应用的深度和广度上,有以下几个方面:(1) 模具粗加工技术向高速发展 (2) 成型表面的加工向精密、自动化发展(3) 光整加工技术向自动化发展(4) 快速成型加工模具技术的发展(5) 模具CAD/CAM技术将有更快的发展二、课题研究的主要内容、研究方法或工程技术方案和准备采取的措施课题研究的主要内容:1、产品成型工艺分析2、模具结构设计3、模具制造工艺研究4、设计模具结构,装配图及零件图5、编制模具制造工艺卡6、撰写设计计算说明书准备措施:1、找好设计的课题,并且分析课题的工艺性,通过查找有关资料计算出工艺尺寸;2、拟订说明书和装配总图,绘出二维的装配总图,打印出说明书。三、现有基础和具备的条件现有基础:本人理论知识扎实,曾多次参加实习。包括金工实习、生产实习和见习等。具有一定的动手能力。具备的条件:1、本院CAD室。2、模具设计手册。3、相关参考书。(主要有模具设计与制造简明手册 冯丙尧 主编 机械工业出版社、冲压与塑压设备 孙风勤 主编 机械工业出版社、冲压工艺与模具设计 钟毓斌 主编 机械工业出版社) 4、学校工厂和实验室的数控机床。四、总的工作任务,进度安排以及预期结果1)总的工作任务:通过自己所学理论知识和专业知识,结合图书馆资料及手头资料,经过老师的指导和同学之间的讨论研究,认真完成外缘翻边圆孔板的设计。 2)进度安排:1、3月23日4月 5 日 开题报告2、4月 6日4月14日 收集资料,确定方案3、4月15日4月30日 模具结构设计4、5月 1 日5月14日 模具工作图样设计5、5月15日5月18日 编制工艺卡及说明书6、5月19日 5月20日 通过指导老师的审定,交毕业设计7、5月21日 5月25日 作好毕业答辩的准备 3)预期的结果:在规定的时间内完成任务,争取在5月20日顺利上交毕业设计定稿,赢得老师的一致好评。希望能在毕业答辩中发挥水平,表现出色。五、指导教师审查意见 指导教师(签名) 年 月 日 六、教研室审查意见 教研室主任(签名) 年 月 日七、院(系)审查意见 院(系)主任(签名) 年 月 日 备 注 邵阳学院毕业设计(论文)前 言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。毕业设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,进行一次冷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。目 录第1章 毕业设计课题与要求(3)第11节 毕业设计课题与要求(3)第2章 模具的设计与计算(4)第21节 整体零件的工艺性分析与方案(4)第22节 拉深,冲孔,切边复合模具设计与计算(5)第23节 工艺与设计计算(7)第24节 计算凸模、凹模、凸凹模工作部分的尺寸(10)第25节 按结构图计算闭合高度(11)第26节 模架的选择(12)第27节 模具各零件详细尺寸的设计(13)第3章 压 力 机 的 选 取(16)第31节 压 力 机 的 选 取(16)后 语 (17)主 要 参 考 文 献(18)第1章 毕业设计课题与要求第1.1节 毕业设计课题与要求1.1.1设计课题对下图一冲压件进行设计,材料为不锈钢,厚度为0.8mm。大批量生产,精度要求不高,可用公差等级为IT14级。1.1.2 设计任务书与要求(1)设计说明书一份。(2) 零件图数份,装配图。第2章 模具的设计与计算第21节 整体零件的工艺性分析与方案2.1.1 冲压件的工艺性分析零件尺寸公差无特殊要求,按IT14级选取,利用拉深,冲孔,切边方式 可达到图件要求。2.1.2 确定工艺方案因该工件属大批量生产,根据零件的生产批量,尺寸精度和材料种类与厚度,选择模具的导向方式与精度,定距方式及卸料方式等,决定采用倒装复合模,这样,对冲裁件的质量才更有保障。复合模有如下特点:(1) 冲裁出来的产品精度高,不受送料误差的影响,内外形相对位置一致性好。(2) 冲件表面较为平整。(3)适宜冲薄料,也适宜冲脆性或软质材料。(4)冲模面积较少。 第22节 拉深,冲孔,切边复合模具设计与计算221 根据零件的形状,故可采取拉深,冲孔,切边复合模具。222 排样和搭边冲裁件在板料、条料或带料上的布置方法称为排样法,简称为排样。排样是否合理,直接影响到材料的利用率,零件质量,生产率,模具结构与寿命等。因此,在冲压工艺中和模具设计中,排样是一项极为重要的技术性很强的工作。(1)根据工件的形状,排样采用直排形式,利用活动挡料销控制送料步距。查模具实用技术设计综合手册表1115最小工艺搭边值,工件间距a1=1.8mm,沿边距a=2.0mm。(2)送料方式采用手动送料送料步距A: A=60+a1=61.8mm条料宽度B: B=D+2(a1+)+C10 -其中为剪板机下料公差,查模具实用技术设计综合手册得 =0.5mmC1为条料入端导料间隙 ,查模具实用技术设计综合手册得 C1=0.1mm故 B=92.2+2(2.0+0.5)+0.10-0.5=97.30-0.5(3)材料利用率的计算一段条料能冲出的工件的重量与这段条料重量之比的百分数称为材料利用率。材料利用率=A/(SB)100A一个步距内工件的有效面积mmS送料步距mmB条料宽度mmA=92.260-4 1721/4-2PI2.22=5253.51mm=5253.51/(61.897.05)100%=87.59%排样图如下:第23节 工艺与设计计算231 冲裁力的计算计算冲裁力的目的是为了确定压力机的额定压力,在生产中冲裁力便可按下式计算: F=LTL冲裁轮廓的总长度T板料厚度 板料的抗拉强度T=0.8mm =450 MpaL=(90.2-32+60-32)2+32 =272.93mm F=0.8450272.93 = 98254.8 N F0=LTK=92.20.84500.8 = 6553.6 N K 为修正系数 L为拉深件截面周长冲孔力 F1=2PI4.40.8450= 9947.52 N232 压力中心的计算因为工件是规则矩形,故其压力中心也就是工件的几何中心。其中心坐标为 X0= 45.1 Y0= 30233 计算各主要零件的尺寸(1) 凹模凹模厚度H:查模具实用技术设计综合手册得K=0.22H = KB = 0.2292.2 = 20.284 凹模取21mm凹模壁厚:根据工件尺寸,可查得C1取40 C2取32所以凹模长L=90.2+ 40 2 = 170.2 mm凹模宽B=58+ 32 2 = 122 mmL B H =170.2 122 21取尺寸为170mm120mm21mm,采用整体式的凹模结构。(2) 凸模固定板凸模固定板的外形与尺寸与凹模相同,厚度H1=0.8H =0.8 21 = 16.8 取16mm(3)垫板 在凸模固定板与上模座之间加一块淬硬的垫板,可避免硬度较低的模座因局部受凸模较大的冲击压力而出现凹陷,致使凸模松动。 垫板一般取610mm,所以取H2=10mm。在垫板上穿连接螺钉,卸料螺钉和定位销处要钻通孔,其直径应比相应件的直径增大0.5mm1mm。(4)卸料橡皮的自由高度 根据工件材料厚度为t=0.8mm。拉深时,凸凹模进入凹模深度0.8mm,考虑模具维修刃磨量为0.8mm,再考虑开始时,卸料板高出凸凹模0.8mm,则总的工作行程:H工作= 4mm,决定选用硬度为邵氏7080A的橡皮,其自由高度H=4/(30%-10%)=20mm聚氨酯橡胶橡皮的预压缩量H压缩=10%20=2mm所以模具中安装橡皮的高度为20-2=18mm(5)卸料板下模卸料板厚度:H0=10mm其开孔大小查模具实用技术设计综合手册表达式1161,得卸料孔每侧与凸凹模保持间隙0.1mm。第24节 计算凸模、凹模、凸凹模工作部分的尺寸 冲孔凸模(2个)。工件孔尺寸4.4,工件尺寸公差等级IT14级,磨损系数 X=0.5。根据冲压工艺与模具设计式2-34凸模刃口尺寸 dp=(d+X)-/ 4 0查G得标准公差数值.30 mmdp=(4.4+0.500.30)0-0.075=4.550-0.075。凸模采用标准型圆凸模形式,其详细结构尺寸见零件图。杳模具实用技术设计综合手册表可得凸凹模双边间隙值为.09 mm。冲孔凸凹模的刃口尺寸按冲孔凸模实际尺寸配作,保证单边间隙为.045 mm。拉深凸凹模的刃口尺寸与工件一致。拉深凸凹模的刃口尺寸按凸凹模实际刃口尺寸配作,保证单边拉深间隙为.88 mm.第25节 按结构图计算闭合高度251 计算闭合高度:模.8+45 = 176.8 mm252 结构图如下:第26节 模架的选择261 模具的相关尺寸:根据凹模的周界尺寸:mm21 mm21 mm,选择模架类型为中间滑动导柱圆形模架,查模具实用技术设计综合手册 表。可确定模架的相关尺寸如下:上模座mm 180 mm 21 mm下模座385 mm 250 mm 45 mm导柱mm 170 mm 32 mm170 mm导套8 mm 100 mm 38 mm 3 2 mm100 mm38 mm最小闭合高度 mm最大闭合高度 mm第27节 模具各零件详细尺寸的设计该模具是采用手工送料倒装拉深、冲孔、切边的复合模。冲孔凸模、凸凹模用固定板紧固,凹模用螺钉与圆柱销固定,送料靠活动挡料销保证送料步距,下模卸料板采用弹性卸料,上模采用刚性卸料。271 推件装置此处设计的推件装置是由压力机的横杆通过打杆、打板、推杆传给推件板。推件板是出件装置中最重要的零件。根据计算,推杆可用2根圆柱头螺钉,其规格为M540 mm。推件板与凹模保证单边.1 mm间隙,其与凸模配合部分取最小间隙,开阶梯孔。这样冲孔凸模因冲孔尺寸较小,能加强其强度,又起到了导向和护套的作用。结构尺寸详见零件图。272 卸料板下模卸料板采用弹压橡皮卸料,卸料板上平面开一定的沉孔,以方便卸料螺钉的活动。273 挡料销挡料销形式采用活动挡料销控制步距,因下方安放了橡皮,直接用圆柱销与卸料板配合,其结构形式如下:274 凸凹模凸凹模型孔侧壁的形状采用阶梯直壁壁孔。台阶形直壁型孔的设计参数有个:一是刃口有效高度,二是漏料孔比型孔单边扩大值b。板料厚度t=0.8 mm时,取mm,b取0.5 mm。结构尺寸如图:275 螺钉、销钉的选择 本模具采用内六角圆柱头螺钉,上模采用 M880 mm 凸凹模与其固定板采用 M650 mm 下模座与卸料板相连采用 M640 mm第3章 压 力 机 的 选 取第31节 压 力 机 的 选 取压力机选用通用小型压力机,根据计算所得的冲裁力选择J2316开式可倾压力机。J2316开式可倾压力机参数如下:公称压力/KN 160达到公称压力时滑块离下止点距离/mm 5滑块行程/mm 70行程次数/(次*mm-1) 115最大封闭高度 (最低) 300 (最高) 160封闭高度调节量/mm 60滑块中心到床身距离/mm 160立柱间距离/mm 220模柄孔尺寸(直径深度)/mm 4060工作台板厚度 60倾斜角/() 30后 语通过本次设计,我对冷冲模,尤其是复合模有了更进一步的了解和认识。对于复合模,不但了解了它的整体结构,而且对它的各个零件的具体结构也有了更进一步的认识 。在加工工艺方面,学会了怎样制作工艺卡,各个工序的先后顺序如何去做,在材料的选取,材料的热处理,模具的装配方面也有了进一步的认识。另外在制图方面也更加熟练了。另外,本次设计得到了刘学敏老师的指导与同学们的支持,在这里特别表示感谢。主 要 参 考 文 献丁聚松主编:冷冲模设计。北京:机械工业出版社,1995孙凤勤主编:模具制造工艺与设计。北京:机械工业出版社,1999钟毓斌主编:冲压工艺与模具设计。北京:机械工业出版社,2001王树勋主编:模具实用技术设计综合手册。广州:华南理工大学出版社,1997李绍林主编:实用模具技术手册。上海:上海科学技术文献出版社,1996冲模设计手册编写组主编:冲模制造手册。北京:北京:机械工业出版社北京:机械工业出版社冲压成形与板材冲压 1 概述通过模具使板材产生塑性变形而获得成品零件的一次成形工艺方法叫做冲压。由于冲压通常在冷态下进行,因此也称为冷冲压。只有当板材厚度超过8100mm时,才采用热冲压。冲压加工的原材料一般为板材或带材,故也称板材冲压。某些非金属板材(如胶木板、云母片、石棉、皮革等)亦可采用冲压成形工艺进行加工。冲压广泛应用于金属制品各行业中,尤其在汽车、仪表、军工、家用电器等工业中占有极其重要的地位。冲压成形需研究工艺设备和模具三类基本问题。 板材冲压具有下列特点: (1)高的材料利用率。(2)可加工薄壁、形状复杂的零件。(3)冲压件在形状和尺寸方面的互换性好。(4)能获得质量轻而强度高、刚性好的零件。(5)生产率高,操作简单,容易实现机械化和自动化。冲压模具制作成本高,因此适合大批量生产。对于小批量、多品种生产,常采用简易冲模,同时引进冲压加工中心等新型设备,以满足市场求新求变的需求。板材冲压常用的金属材料有低碳钢、铜、铝、镁合金及高塑性的合金刚等。如前所述,材料形状有板材和带材。冲压生产设备有剪床和冲床。剪床是用来将板材剪切成具有一定宽度的条料,以供后续冲压工序使用,冲床可用于剪切及成形。 2 冲压成形的特点生产时间中所采用的冲压成形工艺方法有很多,具有多种形式饿名称,但塑性变形本质是相同的。冲压成形具有如下几个非常突出的特点。 (1)垂直于板面方向的单位面积上的压力,其数值不大便足以在板面方向上使板材产生塑性变形。由于垂直于板面方向上的单位面积上压力的素质远小于板面方向上的内应力,所以大多数的冲压变形都可以近似地当作平面应力状态来处理,使其变形力学的分析和工艺参数的计算大呢感工作都得到很大的简化。 (2)由于冲压成形用的板材毛胚的相对厚度很小,在压应力作用下的抗失稳能力也很差,所以在没有抗失稳装置(如压边圈等)的条件下,很难在自由状态下顺利地完成冲压成形过程。因此,以拉应力作用为主的伸长类冲压成形过程多于以压应力作用为主的压缩类成形过程。 (3)冲压成形时,板材毛胚内应力的数值等于或小于材料的屈服应力。在这一点上,冲压成形与体积成形的差别很大。因此,在冲压成形时变形区应力状态中的静水压力成分对成形极限与变形抗力的影响,已失去其在体积成形时的重要程度,有些情况下,甚至可以完全不予考虑,即使有必要考虑时,其处理方法也不相同。 (4)在冲压成形时,模具对板材毛胚作用力所形成的约束作用较轻,不像体积成形(如模锻)是靠与制件形状完全相同的型腔对毛胚进行全面接触而实现的强制成形。在冲压成形中,大多数情况下,板材毛胚都有某种程度的自由度,常常是只有一个表面与模具接触,甚至有时存在板材两侧表面都有于模具接触的变形部分。在这种情况下,这部分毛胚的变形是靠模具对其相邻部分施加的外力实现其控制作用的。例如,球面和锥面零件成形时的悬空部分和管胚端部的卷边成形都属这种情况。 由于冲压成形具有上述一些在变形与力学方面的特点,致使冲压技术也形成了一些与体积成形不同的特点。由于不需要在板材毛的表面施加很大的单位压力即可使其成形,所以在冲压技术中关于模具强度与刚度的研究并不十分重要,相反却发展了学多简易模具技术。由于相同原因,也促使靠气体或液体压力成形的工艺方法得以发展。因冲压成形时的平面应力状态或更为单纯的应变状态(与体积成形相比),当前对冲压成形汇中毛胚的变形与 力能参数方面的研究较为深入,有条件运用合理的科学方法进行冲压加工。借助于电子计算机与先进的测试手段,在对板材性能与冲压变形参数进行实时测量与分析基础上,实现冲压过程智能化控制的研究工作也在开展。人们在对冲压成形过程有离开较为深入的了解后,已经认识到冲压成型与原材料有十分密切的关系。所以,对板材冲压性能即成形性与形状稳定性的研究,目前已成为冲压技术的一个重要内容。对板材冲压性能的研究工作不仅是冲压技术发展的需要,而且也促进了钢铁工业生产技术的发展,为其提高板材的质量提供了一个可靠的基础与依据。 3冲压变形的分类 冲压变形工艺可完成多种工序,其基本工序可分为分离工序和变形工序两大类。分离工序是使胚料的一部分与另一部分相互分离的工艺方法,主要有落料、冲孔、切边、剖切、修整等。其中又以冲孔、落料应用最广。变形工序是使胚料的一部分相对于另一部分产生位移而不破裂的工艺方法,主要有拉深、弯曲、局部成形、胀形、翻边、缩径、校形、旋压等。从本质上看,冲压成形就是毛胚的变形区在外力的作用下产生相应的塑性变形,所以变形区内的应力状态和变形特点景象的冲压成形分类,可以把成形性质相同的成形方法概括成同一个类型并进行体系化的研究。绝大多数冲压成形时毛胚变形区均处于平面应力状态。通常认为在板材表面上不受外力的作用,即使有外力作用,其数值也是较小的,所以可以认为垂直于板面方向上的应力为零,使板材毛胚产生塑性变形的是作用于板面方向上相互的两个主应力。由于板厚较小,通常都近似地认为这两个主应力在厚度方向上是均匀分布的。基于这样的分析,可以把各种形式冲压成型中的毛陪变形区的受力状态与变形特点,在平面应力的应力坐标系中与相应的两向应变坐标系中以应力与应变坐标决定的位置来表示。4.冲压用原材料 冲压加工用原材料有很多种,它们的性能也有很大的差别,所以必须根据原材料的性能与特点,采用不同的冲压成形方法、工艺参数和模具结构,才能达到冲压加工的目的。由于人们对冲压成形过程板材毛胚的变形行为有了较为深入的认识,已经相当清楚的建立了由原材料的化学成分、组织等因素所决定的材料性能与冲压成形之间的关系,这就使原材料生产部门不但按照冲压件的工作条件与使用要求进行原材料的设计工作,而且也根据冲压件加工过程对板材性能的要求进行新型材料的开发工作,这是冲压技术在原材料研究方面的一个重要方向。对冲压用原材料冲压性能方面的研究工作有(1)原材料冲压性能的含义。(2)判断原材料冲压性能的科学方法,确定可以确切反映材料冲压性能的参数,建立冲压性能的参数与实际冲压成形间的关系,以及冲压性能参数的测试方法等。 (3)建立原材料的化学成分、组织和制造过程与冲压性能之间的关系。冲压用原材料主要是各种金属与非金属板材。金属板材包括各种黑色技术和有色金属板材。虽然在冲压生产中所用金属板材的种类很多,但最多的原材料蛀牙是钢板、不锈钢板、铝合金板及各种复合金属板。5板材冲压性能及其鉴定方法 板材是指对冲压加工的适应能力。对板材冲压性能的研究具有飞行重要的意义。为了能够运用最科学与最经济合理的冲压工艺过程与工艺参数制造出冲压零件,必须对作为加工对象的板材的性能具有十分清楚的了解,这样才有可能充分地利用板材在加工方面的潜在能力。另一方面,为了能够依据冲压件的形状与尺寸特点及其所需的成形工艺等基本因素,正确、合理地选用板材,也必须对板材的冲压性能有一个科学的认识与正确的判断。评定板材冲压性能的方法有直接试验法与间接试验法。 实物冲压试验是最直接的板材冲压性能的评定方法。利用实际生产设备与模具,在与生产完全相同的条件下进行实际冲压零件的性能评定,当然能够的最可靠的结果。但是,这种评定方法不具有普遍意义,不能作为行业之间的通用标准进行信息的交流。 模拟试验是把生产中实际存在的冲压成形方法进行归纳与简单化处理,消除许多过于复杂的因素,利用轴对称的简化了的成形方法,在保证试验中板材的变形性质与应力状态都与实际冲压成形相同的条件下进行的冲压性能的评定工作。为了保证模拟试验结果的可靠性与通用性,规定了私分具体的关于试验用工具的几何形状与尺寸、毛胚的尺寸、试验条件(冲压速度、润滑方法、压边力等)。 间接试验法也叫做基础试验法。间接试验法的特点是:在对板材在塑性变形过程中所表现出的基本性质与规律进行分析与研究的基础上,进一步把它和具体的冲压成形中板材的塑性变形参数联系起来,建立间接试验结果(间接试验值)与具体的冲压成形性能(工艺参数)之间的相关性。由于间接试验时所用试件的形状与尺寸以及加载的方式等都不同于具体的冲压成形过程,所以它的变形性质和应力状态也不同于冲压变形。因此间接试验所得的结果(试验值)并不是冲压成形的工艺参数,而是可以用来表示板材冲压性能的基础性参数。Characteristics and Sheet Metal Forming1 The article overview Stamping is a kind of plastic forming process in which a part is produced by means of the plastic forming the material under the action of a die. Stamping is usually carried out under cold state, so it is also called stamping. Heat stamping is used only when the blank thickness is greater than 8100mm. The blank material for stamping is usually in the form of sheet or strip, and therefore it is also called sheet metal forming. Some non-metal sheets (such as plywood, mica sheet, asbestos, leather)can also be formed by stamping. Stamping is widely used in various fields of the metalworking industry, and it plays a crucial role in the industries for manufacturing automobiles, instruments, military parts and household electrical appliances, etc. The process, equipment and die are the three foundational problems that needed to be studied in stamping. The characteristics of the sheet metal forming are as follows: (1) High material utilization (2) Capacity to produce thin-walled parts of complex shape. (3) Good interchangeability between stamping parts due to precision in shapeand dimension. (4) Parts with lightweight, high-strength and fine rigidity can be obtained. (5) High productivity, easy to operate and to realize mechanization and automatization. The manufacture of the stamping die is costly, and therefore it only fits to mass production. For the manufacture of products in small batch and rich variety, the simple stamping die and the new equipment such as a stamping machining center, are usually adopted to meet the market demands. The materials for sheet metal stamping include mild steel, copper, aluminum, magnesium alloy and high-plasticity alloy-steel, etc.Stamping equipment includes plate shear punching press. The former shears plate into strips with a definite width, which would be pressed later. The later can be used both in shearing and forming. 2Characteristics of stamping forming There are various processes of stamping forming with different working patterns and names. But these processes are similar to each other in plastic deformation. There are following conspicuous characteristics in stamping: (1)The force per unit area perpendicular to the blank surface is not large but is enough to cause the material plastic deformation. It is much less than the inner stresses on the plate plane directions. In most cases stamping forming can be treated approximately as that of the plane stress state to simplify vastly the theoretical analysis and the calculation of the process parameters. (2)Due to the small relative thickness, the anti-instability capability of the blank is weak under compressive stress. As a result, the stamping process is difficult to proceed successfully without using the anti-instability device (such as blank holder). Therefore the varieties of the stamping processes dominated by tensile stress are more than dominated by compressive stress. (3)During stamping forming, the inner stress of the blank is equal to or sometimes less than the yield stress of the material. In this point, the stamping is different from the bulk forming. During stamping forming, the influence of the hydrostatic pressure of the stress state in the deformation zone to the forming limit and the deformation resistance is not so important as to the bulk forming. In some circumstances, such influence may be neglected. Even in the case when this influence should be considered, the treating method is also different from that of bulk forming. (4)In stamping forming, the restrain action of the die to the blank is not severs as in the case of the bulk forming (such as die forging). In bulk forming, the constraint forming is proceeded by the die with exactly the same shape of the part. Whereas in stamping, in most cases, the blank has a certain degree of freedom, only one surface of the blank contacts with the die. In some extra cases, such as the forming of the blank on the deforming zone contact with the die. The deformation in these regions are caused and controlled by the die applying an external force to its adjacent area. Due to the characteristics of stamping deformation and mechanics mentioned above, the stamping technique is different form the bulk metal forming: The importance or the strength and rigidity of the die in stamping forming is less than that in bulk forming because the blank can be formed without applying large pressure per unit area on its surface. Instead, the techniques of the simple die and the pneumatic and hydraulic forming are developed. Due to the plane stress or simple strain state in comparison with bulk forming, more research on deformation or force and power parameters has been done. Stamping forming can be performed by more reasonable scientific methods. Based on the real time measurement and analysis on the sheet metal properties and stamping parameters, by means of computer and some modern testing apparatus, research on the intellectualized control of stamping process is also in proceeding. It is shown that there is a close relationship between stamping forming and raw material. The research on the properties of the stamping forming, that is, forming ability and shape stability, has become a key point in stamping technology development, but also enhances the manufacturing technique of iron and steel industry, and provides a reliable foundation for increasing sheet metal quality. 3Categories of stamping forming Many deformation processes can be done by stamping, the basic processes of the stamping can be divided into two kinds: cutting and forming.Cutting is a shearing process that one part of the blank is cut from the other. It mainly includes blanking, punching, trimming, parting and shaving, where punching and blanking are the most widely used. Forming is a process that one part of the blank has some displacement from the other. It mainly includes deep drawing, bending, local forming, bulging, flanging, necking, sizing and spinning. In substance, stamping forming is such that the plastic deformation occurs in the deformation zone of the stamping blank caused by the external force. The stress state and deformation characteristic of the deformation zone are the basic factors to decide the properties of the stamping forming. Based on the stress state and deformation characteristics of the deformation zone, the forming methods can be divided into several categories with the same forming properties and be studied systematically.The deformation zone in almost all types of stamping forming is in the plane stress state. Usually there is no force or only small force applied on the blank surface. When is assumed that the stress perpendicular to the blank surface equals to zero, two principal stresses perpendicular to each other and act on the blank surface produce the plastic deformation of the material. Due to the small thickness of the blank, it is assumed approximately the two principal stresses distribute uniformly along the thickness direction. Based on this analysis, the stress state and the deformation characteristics of the deformation zone in all kinds of stamping forming can be denoted by the points in the coordinates of the plane principal stresses and the coordinates of the corresponding plane principal strains. 4Raw materials for stamping formingThere are a lot of raw materials used in stamping forming, and the properties of these materials may have large difference. The stamping forming can be succeeded only by determining the stamping method, the forming parameters and the die structures according to the properties and characteristics of the raw materials. The deformation of the blank during stamping forming has been investigated quite thoroughly. The relationships between the material properties decided by the chemistry component and structure of the material and the stamping forming has been established clearly. Not only the proper material can be selected based on the working condition and usage demand, but also the new material can be developed according to the demands of the blank properties during processing the stamping part. This is an important domain in stamping forming research. The research on the material properties for stamping forming is as follows: (1)Definition of the stamping property of the material. (2)Method to judge the stamping property of the material, find parameters to express the definitely material property of the stamping forming, establish the relationship between the property parameters and the practical stamping forming, and investigate the testing methods of the property parameters. (3)Establish the relationship among the chemical component, structure, manufacturing process and stamping property. The raw materials for stamping forming mainly include various metals and nonmetal plate. Sheet metal includes both ferrous and nonferrous metals. Although a lot of sheet metals are used in stamping forming, the most widely used materials are steel, stainless steel, aluminum alloy and various composite metal plates. 5Stamping forming property of sheet metal and its assessing methodThe stamping forming property of the sheet metal is the adaptation capability of the sheet metal to stamping forming. It has crucial meaning to the investigation of the stamping forming property of the sheet metal. In order to produce stamping forming parts with most scientific, economic and rational stamping forming process and forming parameters, it is necessary to understand clearly the properties of the sheet metal, so as to utilize the potential of the sheet metal fully in the production. On the other hand, to select plate material accurately and rationally in accordance with the characteristics of the shape and dimension of the stamping forming part and its forming technique is also necessary so that a scientific understanding and accurate judgment to the stamping forming properties of the sheet metal may be achieved. There are direct and indirect testing methods to assess the stamping property of the sheet metal.Practicality stamping test is the most direct method to assess stamping forming property of the sheet metal. This test is done exactly in the same condition as actual production by using the practical equipment and dies. Surely, this test result is most reliable. But this kind of assessing method is not comprehensively applicable, and cannot be shared as a commonly used standard between factories. The simulation test is a kind of assessing method that after simplifying and summing up actual stamping forming methods, as well as eliminating many trivial factors, the stamping properties of the sheet metal are assessed, based on simplified axial-symmetric forming method under the same deformation and stress states between the testing plate and the actual forming states. In order to guarantee the reliability and generality of simulation results, a lot of factors are regulated in detail, such as the shape and dimension of tools for test, blank dimension and testing conditions(stamping velocity, lubrication method and blank holding force, etc).Indirect testing method is also called basic testing method its characteristic is to connect analysis and research on fundamental property and principle of the sheet metal during plastic deformation, and with the plastic deformation parameters of the sheet metal in actual stamping forming, and then to establish the relationship between the indirect testing results(indirect testing value) and the actual stamping forming property (forming parameters). Because the shape and dimension of the specimen and the loading pattern of the indirect testing are different from the actual stamping forming, the deformation characteristics and stress states of the indirect test are different from those of the actual one. So, the results obtained form the indirect test are not the stamping forming parameters, but are the fundamental parameters that can be used to represent the stamping forming property of the sheet metal.
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