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i外文资料与中文翻译外文资料：Analysis on The Factors of Impacting on The Life of Stamping DieREN Hai-dongYU LingAbstract：Stamping is a wide range of material processing methods，stamping die is equipment to achieve the important parts of theprocessing，whose life directly afects quality an d cost ofthe productThis article analyzes to its influencing factors，finding a method tosolveproblems，andimprovethelifeof stamping dieKeywords：Samping die；life；Infl uencing factoIs the use of stamping presses installed in the die pressure on the material to produce plastic deformation or separation in order to obtain the parts needed for a pressure processing method. In industrial production, especially in household appliances, automotive, aerospace and engineering fields such as instrumentation is widely available. The die is the realization of this important technology components and equipment for processing. Die as a result of a long cycle of production and processing, the use of the high cost of materials, manufacturing costs in product cost of production occupies a significant proportion, therefore, to improve the life of stamping dies is very important. Through the use of molds, for various reasons can not be a reproduction of the red pieces of qualified, could no longer be repaired, which is commonly referred to as die failure. Die life by various forms of limitations expired, common are: wear failure, failure deformation, fracture failure and failure, such as bite wounds. Stamping processes, as well as due to different working conditions of the different effects of stamping die failure are many factors, but the same factors may also bring some form of failure. In this paper, an analysis of its influencing factors, possible solutions to the problem in order to achieve the purpose of die life.1 Mold DesignMold design, including structural design and parts design. The structure of mold not only affects the quality of parts produced to determine the productivity of enterprises and processing methods, but also to improve the life of mold also has a key role. Therefore, before designers to make full preparations to meet the production tooling to optimize the structure at the same time.1.1 Parts of Product DesignReasonable product design will help improve the life of mold. If the product has a cusp, or fillet radius is too small, the design of the edge will die due to stress concentration and cracking. Without prejudice to the structure and function of products, we can change the design of some of its unreasonable.1.2 Die Structure DesignReasonable structure can improve the die life. For example, in Die, the direction to improve the convex and concave stamping die in the course of the relative stability, thus ensuring the mold space at a reasonable framework of blanking blanking. And the reasonableness of blanking clearance and stability to improve die life is an important measure. Accurate reduced-oriented relationship between the relative movement of the wear and tear of parts and components to avoid the convex, concave die as a result of unreasonable gap a bite injuries and other forms of failure. Particularly in the Fine Blanking Die, the high-precision mold-oriented institutions is to ensure that the structural design of an important guarantee for success. Therefore in order to improve the life of mold, the form must be the right choice and guide precision-oriented. The choice of orientation should be higher than the accuracy of convex and concave mold with precision. For more blanking punch, punch in a number of large difference in diameter, there is a difference and close the case that if a small and a long punch, then easily lead to instability or break. We can punch arranged in Figure 1 (a) ladder-style in order to increase its stiffness. Punching holes for the need to increase the punch guide in order to enhance the strength of punch, which is to ensure the normal work of stamping dies to the premise. Which can increase many-oriented approach, to be used in Figure 1 (b) shown in the front and the entire process-oriented and other-oriented.Figure 1 (a) ladder layout punch 1 (b) punch-orientedAccurate calculation of the process can also increase mold life. Such as discharge power and the calculation of stroke. If we are not allowed to easily spring fatigue fracture or failure. Die on a high degree of calculation, as well as the choice of press and reasonable manner and location-oriented institutions can effectively improve the die life. Modulus of continuity for the design and layout of the ride side of the calculation of size is also crucial.1.3 Die gapStamping dies when space is the convex, concave die size difference between the horizontal edge. Gap on the impact of a large die life is a stamping process and die design of an extremely important issue. Convex, concave die gap size of a direct impact on product quality and mold the life space is too large or too small will cause the edge passivation or wear and tear (as shown in Figure 2). Die materials drop to die later, punch to punch prevail, and these two dimensions has been the impact of space. The experimental results show that the thickness of the gap below 2 percent, prone punch damage, space for more than 6%, there had been errors in parts size. Gap in the thickness of 4% 5%, the effect of blanking good stability. Die gap, therefore the correct choice is to ensure that an important way to die life. At present, the choice of space data in addition to investigations, the most by the actual experience.(a) gap is too small (b) a reasonable gap (c) gap is too largeFigure 2 gap on the impact of stampings2 Die ManufacturingMold manufacturing process design is reasonable, to ensure that mold is an important way of life. Most of mold manufacturing parts of the process can be carried out in accordance with the normal, but there are special requirements for spare parts or spare parts for local processing, will need to have some special methods.2.1 Mechanical RoughMaterial machining accuracy of the assembly of the mold affects accuracy, it will directly affect the mold of parallelism, perpendicularity and coaxiality. In addition, the marks left rough, worn, are prone to stress concentration sites, but also occurred in the early fatigue cracks and the local.2.2 Heat TreatmentHeat Treatment in the manufacture of stamping die plays a very important role, in spite of different types and different structure of mold, the use of different steel products, or using different machining and processing of shape, but they need to use heat treatment process to obtain a higher hardness and wear resistance, as well as other mechanical properties required. In general, the die service life and quality of products produced to a large extent depends on the quality of heat treatment processing. Thus, in die manufacturing, and continuously improve the skill level of heat treatment, a reasonable template to improve the performance of internal organization and working methods, it is particularly important. Heat treatment time and temperature is an important factor, because of the time in different temperatures, heat treatment may constitute a different form, the main annealing, normalizing, quenching and tempering, and carburizing, nitriding, carbonitriding, etc. For example, in the blanking die, because people punch wedge material is the work of more serious wear and tear parts, so the hardness should be greater in general for the HRC 60 63, die for the HRC 57 60, this kind of hardness than the two , or die punch hardness is higher than the longer die life.3 Die Assembly and DebuggingAssembly is the key to mold production process. A direct impact on the quality of the die assembly of the quality of parts, dies and the life of the state of the technology. Die assembly includes two aspects: (1) good parts of each machining process in accordance with requirements of drawings assembled into a general assembly and assembly; (2) in the assembly process as part of the processing work. Die in the assembly as an example, the technical requirements is to ensure consistency blanking gap and ensure the accuracy of direction-oriented institutions, as well as the movement to ensure that all relevant pieces of die design in accordance with strict technical parameters. This is a debugging tool to ensure a successful and smooth conduct of the production protection, but also to ensure that an important factor in mold life. In recent years, with the development of the production, users are vulnerable to damage parts of the swap request, so that users die at the scene of the rapid replacement of damaged parts. Die before the test mode, it should also be designed in strict accordance with the technical parameters of the model to select press. It is closely related to the length of die life. Press the stiffness, precision, crucial parameters such as tonnage. Press one of the stiffness of stiffness by the bed, transmission stiffness and rigidity of three parts-oriented, if less stiffness, load and unloading end, the die gap, great changes will happen, it will affect the accuracy of stamping parts and mold life. Die after assembly, must be red and adjust the test can be used for production. In order to protect the mold, the first time in debugging, it is necessary to pay attention to the use of paper or aluminum, as well as cold-rolled plate red test. To ensure that edge punch die edge into the depth of the scope of a reasonable (usually for a material thickness). Stamping die so red when the level of stress and wear and tear will be minimal, and fully protect the convex and concave mold, increased die life. The purpose of debugging and the task is: to die out not only qualified stampings, security and stability but also put into production use. Should be based on examination of stamping defects, analysis of its causes and try to solve them. Some bending, deep drawing and flanging, etc. so that the deformation of sheet metal dies, stamping parts, when the shape of complex or high accuracy, it is difficult to accurately calculate the deformation of the former size and shape of the rough. For this type of stamping parts, although the relevant references are rough calculation methods and formulas, but the impact of plastic deformation as a result of many factors, calculated from the size and needs of different size. In the actual production in order to obtain more accurate size, often determined through experiments. Red in the test set to adjust the size of blank.4 ConclusionStamping die life impact of a number of factors, from the above analysis we can see from the mold design to the use of the entire process can improve the die life. Practice has proved that the rational design of die structure and the shape of the die using the appropriate manufacturing processes, heat treatment process, so that die in the normal conditions, can increase the mold life.References: 1 Weng its gold. Cold stamping technology M. Beijing: Mechanical Industry Press, 2007. 2 Liu, ZHANG Bao-zhong. Stamping die design and manufacture of M. Beijing: Higher Education Publishing Agency. 2006. 3Xiaopei.wang. Stamping Manual M. Beijing: Mechanical Industry Press, 2006.中文翻译：影响冲压模具寿命的因素分析任海东，于玲摘要：冲压成形是一种应用广泛的材料加工方法，冲压模具是实现零件加工的重要工艺装备，它的使用寿命直接影响到产品的质量和成本。对模具寿命的影响因素加以分析，找出解决问题的方法，从而达到提高模具寿命的目的。关键词：冲压模具：寿命；影响因素冲压是利用安装在压力机上的冲模对材料施加压力，使其产生分离或塑性变形，从而获得所需要的零件的一种压力加工方法。它在工业生产中，尤其是在家用电器、汽车、航空以及仪器仪表等工程领域获得广泛应用。而冲模就是实现这一零件加工的重要工艺装备。由于模具的生产加工周期长，使用的材料费用高，制造成本在产品生产成本中占有相当大的比例，因此，提高冲压模具的寿命是非常重要的。模具经过使用，由于种种原因不能再生产出合格的冲件，也不能再修复，这种情况一般称为模具失效。模具寿命受各种失效形式的限制，常见的有：磨损失效、变形失效、断裂失效及啃伤失效等。由于冲压工序不同以及工作条件的不同，影响冲压模具失效的因素很多，而同一种因素也可能带来几种失效形式。本文对其影响因素进行分析，找出解决问题的方法，从而达到提高模具寿命的目的。1 模具设计模具设计包括结构设计和零部件设计。模具的结构不仅能影响到所生产零件的质量，决定企业的生产效率和加工方式，而且对提高模具的使用寿命也具有关键的作用。因此设计者在设计之前，要做好充分的准备工作，在满足生产的同时尽可能优化模具结构。11 零件产品设计合理的产品设计有利于提高模具的寿命。如果产品具有尖角，或圆角半径太小，所设计的凹模刃口就会因应力集中而开裂。在不影响产品结构和功能的前提下，我们可以改变其一些不合理的设计。12 模具结构设计合理的结构可以提高模具的寿命。例如在冲裁模中，导向机构提高了凸、凹模在冲压过程中的相对稳定性，从而保证模具在合理的冲裁间隙范围内进行冲裁。而冲裁间隙的合理性及稳定性正是提高模具寿命的重要措施。精确的导向减少了有相对运动关系的零部件的磨损，避免了凸、凹模由于间隙不合理出现“啃伤”等失效形式。尤其在精密冲裁模中，高精度的导向机构是确保模具结构设计成功的重要保障。因而为了提高模具的寿命，必须正确选择导向形式和导向精度。导向精度的选择应高于凸、凹模的配合精度。对于多凸模冲裁，在几个凸模直径相差较大，相距又很近的情况下，如果小凸模细小而又较长，则容易造成失稳或折断。我们可以把凸模布置成如图1(a)阶梯式的，以增加其刚度。对于小孔冲裁，必须增加对凸模的导向，以提高凸模的强度，这是保证冲压模具能正常工作的前提。其中能增加导向的方法很多，可采用如图1(b)所示的前端导向和全程导向等。准确的工艺计算也可以提高模具的寿命。如卸料力及行程的计算。若计算不准，容易造成弹簧的疲劳断裂或失效。对合模高度的计算以及压力机的选择，合理的定位方式及导向机构等，都可以有效地提高模具的使用寿命。对于连续模排样的设计和搭边尺寸的计算也至关重要。13 模具间隙模具间隙是指冲压时凸、凹模刃口横向尺寸之差。间隙对模具寿命的影响很大，是冲压工艺与模具设计中的一个极其重要的问题。凸、凹模间隙的大小直接影响产品的质量和模具的使用寿命，间隙过大或过小都会使刃口钝化或磨损(如图2所示)。冲裁模中落料一般以凹模为准，冲孔以凸模为准，而这两个尺寸又受到间隙的影响。实验表明，间隙在板厚的2以下时，凸模容易发生损坏，间隙在6以上时，制件尺寸出现误差。间隙在板厚4 5时，冲裁稳定效果好。因此正确选择模具间隙，是保证模具寿命的重要途径。目前，间隙的选择除了查资料以外，大部分靠实际经验获得。2 模具制造模具制造工艺设计的合理性，也是保证模具寿命的重要途径。大部分模具零件的制造可以按正常的工艺进行，但对有特别要求的零件或零件局部加工，就需要有一定特殊的方法。21 机械粗加工材料的加工精度对模具的装配精度有很大的影响，将直接影响模具的平行度、垂直度和同轴度。另外，粗加工留下的刀痕、磨痕，都是容易产生应力集中的部位，也是早期产生裂纹和发生疲劳的地方。22 热处理热处理在冲压模具的制造中起着很重要的作用，尽管不同类型及不同的结构模具，使用不同的钢材，或采用不同的机械加工及加工成形，但都需要用热处理的加工方法，使其获得较高的硬度和耐磨性，以及其他所要求的力学性能。一般来说，冲模的使用寿命及生产出来的产品质量，在很大程度上取决于热处理加工质量因此，在冲模制造中，不断提高热处理的技术水平，合理的改进模板内部组织和性能的工作方法，就显得格外的重要。时间和温度是热处理的重要因素，由于时间温度的不同，可构成不同的热处理形式，其主要有退火、正火、淬火、回火和渗碳、渗氮、碳氮共渗等。比如在冲裁模中，由于凸模楔人材料，是磨损比较严重的工作零件，所以其硬度应大些，一般为HRC 6063，凹模为HRC 5760，这样比两者硬度样，或凹模硬度高于凸模的模具寿命更长一些。3 模具装配及调试装配是模具生产中的关键工序。冲模装配质量直接影响制件的质量、冲模的技术状态和使用寿命。冲模的装配工作包括两方面的内容：(1)将每个加工好的零件按图纸工艺要求装配成组合件及总体装配；(2)在装配过程中进行的一部分加工工作。以冲裁模的装配为例，其技术要求是保证冲裁间隙一致性，保证导向机构的导向精度，以及保证各相关运动件能够按照模具设计的技术参数严格进行。这是保证模具调试成功及生产能够顺利进行的保障，也是确保模具寿命的重要因素。近年来，随着生产的发展，用户对易损坏零件提出了互换要求，以便用户在现场对模具损坏零件的迅速更换。模具在试模前，还应该严格按照设计的技术参数来选择压力机的型号。它关系到模具使用寿命的长短。压力机的刚度、精度、吨位等参数至关重要。其中压力机的刚度是由床身刚度、传动刚度和导向刚度三部分组成，如果刚度较差，负载终了和卸载时，模具间隙会发生很大变化，将会影响到冲压件的精度和模具寿命。模具装配完后，必须经过试冲和调整，才能进行生产使用。为了保护模具，在第一次调试时，要注意利用纸片或铝片以及冷轧板进行试冲。保证凸模刃口进入到凹模刃口的深度在合理的范围内(一般为一个料厚)。这样模具冲压时的冲压力及磨损程度会最小，充分保护了凸、凹模，提高了模具寿命。调试的目的和任务是：使冲模不仅能冲出合格的冲压件，而且能安全稳定的投入生产使用。应根据试冲件中出现的缺陷，分析其产生的原因，设法加以解决。有些弯曲、拉深及翻边等使板料变形的冲模，当冲压件的形状复杂或精度较高时，很难精确计算出变形前的毛坯尺寸和形状。对于这一类冲压件，虽然相关参考资料都有计算毛坯的方法和公式，但由于影响塑性变形的因素非常多，计算出来的尺寸和实际的需要尺寸是有差别的。在实际的生产中为了得到较准确的尺寸，往往通过试验来确定即在试冲调整中确定毛坯的尺寸。4 结论影响冲压模具寿命的因素很多，从以上分析可以看出从模具设计到使用的全过程中，均能提高模具寿命。实践证明，合理设计模具结构及形状，采用恰当的冲模制造工艺、热处理工艺，使模具在正常的条件下工作，均能提高模具的寿命。参考文献：1翁其金冷冲压技术M北京：机械工业出版社，20072刘建超，张宝忠冲压模具设计与制造M北京：高等教育出版社。20063王孝培冲压手册M北京：机械工业出版社，200614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. 5St
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