汽车转向灯遮光罩成形工艺与级进模设计外文翻译及原文..docx

1、上海应用技术学院机械工程学院毕业设计（论文）外文翻译题目 汽车转向灯遮光罩成形工艺与级进模设计学生姓名郭蔚铭专业材料成型及控制工程学号0910231230班级09102312指导教师聂文忠职称副教授2013年3月译文一提高级进模性能级进模是一种成本低廉且安全的零件制造方法 ,. 精心设计模具结构可确保最佳性能。一副级进模在一次冲压动作中可在模具不同工位进行不同的冲压操作。这些在通过模具的带料上同时进行的冲压动作制造出零件。 每个工位可进行一个或多个操作， 但要生产出完整的零件条料必须经过每一个工位。 而零件依靠零件之间的载体输送到各个工位，并在最后一个工位进行切除。为了使模具性能最佳，在设计和

2、制造级进模具时，必须考虑以下五个方面：研究零件送料方式零件顶出和送进设计零件载体压料装置零件排样设计级进模首先必须正确地理解零件图， 必须考虑材料、 重要表面、 孔的尺寸和和位置、毛刺方向、材料纤维方向、表面粗糙度和其他因素。模具设计要求设计者必须对零件有透澈的了解， 特别是对形状和轮廓不规则的零件。然而，现代计算机绘图使得零件数据可以直接下载到设计者的电脑上，使得设计者可能不熟悉零件重要特性。另外 , 因为计算机绘图经常出现这种情况，图上只显示一个面，可能是内表面也可能是外表面， 使得很多计算机绘制的图形难以看懂。电脑绘图经常显示所有的线条，包括隐藏部分，为实线而非虚线，这导致错误，进而导致

3、模具结构错误。为了更好地看懂复杂零件外形，可用蜡板，橡胶皮或者木板做成具有零件某个视图方向上的外形的模型。 模型不要求精确的尺寸， 其主要是用来形象地表示零件形状。也可以用这些模型来决定应该在级进模的哪个工位成形零件哪个部分的外形。材料送进必须确保条料准确地进入模具。如果条料导向错误，那么最初的10 次冲压动作对模具造成的损伤可能比接下来的100000 次冲裁还大。当卷料送进入模具时必须顺利导向且有限位装置。 良好的导向能力时非常重要的， 因为这样操作人员就不必将手伸入模具，而且可以缩短接上下一卷材料所需的时间。除此之外，导向装置必须时可调的以适应条料宽度的变化。 对第一次冲裁而言条料送进位置

4、非常重要，必须确定条料在每个工位的送进位置的以保证凸模不冲偏， 会导致冲头变形或切不完整， 可能造成条料不平衡送进时单侧受力。 任一种可能都会造成凸凹模错位使得冲头受剪切损坏。条料送进不当成形时可能导致偏载或者边缘卷起， 影响上下模之间的相对位置。垫块必须能够承受这些载荷，特别是成形较厚材料时更应如此。一个步距的凹口或止动销可作为定位点控制条料送进位置， 黄铜标签或标记槽也提供了视觉定位 ，但是这些都不够准确，不够有效。通过在将步距限位销安装在支点上，并用限位开关监控以防止条料送进不到位或送进过多以保护压力机。零件顶出和送进级进模通常要求将条料抬高到距模具工作位置一定高度水平线上， 使得条料送

5、进到指定位置，而与清理废料和毛刺或者利用制件外形清理模具无关。正常情况下，所有抬高装置必须上升到同一高度使条料在送进过程中保持水平。条料不能由凹陷， 否则零件会被从正确位置拔出。 相对于安排在条料侧面的弹簧销和球头抬料销，杆式抬料装置效果更好。多数时候一旦材料送进问题解决， 则要求杆式抬料装置可以承受较高的冲压速率。虽然成本比球头抬料装置高，但性能要好的多，而且安装时间也缩短了。一旦条料进入导料槽， 条料就必须能够自动送进到所有后续工位而不需要人工在每个导向位置或抬料处对准导向。 而且条料在抬料杆上应该保持平衡不在送进是偏向一侧。 在抬料杆头部应装上一个金属帽盖， 形成一个凹槽， 在条料送进时

6、拖住条料不使其弯曲变形。送进步距测量和抬料装置的设置方案可通过在模具设计时用一块与条料等宽度的透明纸板模拟条料来确定。 纸板边缘位于根据模具设计方案确定的第一工位冲裁时条料应送进的位置， 然后在纸板上标示模具第一个工位所要进行的的所有操作比如： 切槽和冲孔。 接着将纸带移动到第二个拉深工位， 并在纸板上标示该工位进行的操作。 在每个工位重复该操作则可在纸带上显示出送到最后工位时条料的形状，在根据条料形状设置定距和抬料装置。为将条料从一个工位运送到下一个工位， 必须在条料上的零件之间留下部分材料作为运送条料前进的载体。 这些载体可以是条料条料间的十字形部分或者由几条窄条带，如边侧载体。零件在进行

7、翻边， 成形或者拉深操作时要求边缘材料向内流动， 这就需要载体在模具工作期间能够横向移动或垂直收缩， 或两者都有。需要给载体提供足够的活动空间，使得载体收缩和移动时不会将相邻的零件拽离原来位置另一个需要关注的问题是材料在压力机开合模具期间的垂直运动。 如，有的零件需要几次才能拉深成形，在这些工位之间材料就发生垂直流动。与压力机下行时相同，必须注意压力机上行时要保证载体运动灵活，因为载体向上运动可能会与向下运动有所不同。可在模具设计阶段做零件轮廓，压边圈和固定钢板的轮廓， 然后按顺序放在模具断面视图之上，将这些零件根据相对之间的关系向下运动就可以模拟冲压过程中上模是怎样合模的，可显示出开合模时零

8、件之间的相对位置。零件载体所有级进模的共同点是零件靠坯料上的材料运送到模具中的各个工位， 这些材料有各种不同的术语称呼，如载体，筋，条带，连接带等等。在本例中，我们一概称之为载体，其主要有以下五种形式：原载体所有操作可在零件上完成，不需要事先切出载体。中间载体 先切出零件形状， 留下靠近中间的一段条带。 适用与在周边进行切除工序的零件。如果载体宽度较大，允许在单侧切出零件。等宽双侧载体 条带对称分布在零件两侧， 用一段窄长的条料运送零件， 适用于须切除零件之间材料的零件。边料载体 载体在零件的边缘，适用于在中间成形的零件。单侧载体 载体位于零件一侧， 运送零件到最后一个工位或中间工位， 可在零

9、件三个方向上成形。根据零件在级进工位中成形的不同要求， 载体有各种不同的类型。 可在模具闭合期间没有运动的坯料边缘留余料或在做一个或两个甚至三个缺口作为载体。根据载体在零件上的连接点的位置和易于模具废料切除， 载体可以是直的或者有弧度的环形。 在成形，翻边或拉深杯筒形零件时， 模具开合时载体还可以横向或向上和向下移动。模具工作时可能使得载体移动， 要求载体具有伸缩性。撇开载体伸缩性不论，载体的主要功能是将零件尽可能地运送到离模具下个工位的定距、定位装置尽可能近的位置，以便进行精确定位。最佳载体形状载体形状是否合理由以下决定：零件之间的空位部分： 尽量使载体在坯料横向宽度和纵向步距之内，如果不能

10、满足这个条件， 则设计人员需要考虑是否增加条料宽度或步距以保证载体的尺寸。载体与零件连接部分：如果由两个载体，尽量使两个载体的形状和长度大小一致，以使两个载体韧性和灵活性相同。凸凹模的清理：模具闭合时凸模进入坯料以下或者凹模升到坯料之上，要求开模时将相应的零件或废料推出。 如果载体与模块相干涉，可将载体纵向设置以便清理。材料厚度： 大型薄壁零件需要需要设加强筋以加强载体强度，方便条料送进。另一加强刚度和导向能力的方式是在坯料上开一缺口或将边缘折起，这也可以作为定距。如果载体伸长过多则下一个工位零件无法准确定位， 而如果有两个载体， 一个伸长而另一个没伸长，也会导致定位不好。在载体上打一个凹坑可

11、防止载体伸长。如果中心载体或单侧载体拱起变形，可用压痕进行矫正。 设计凹痕结构并在凸模上打上相同形状的印记，则可以很容易地进行侧向和垂直方向定位。条料边缘翘曲是由于卷片筒使得条料与模具的导料装置相碰而引起的，使得条料边缘卷起， 并最终导致条料送进不到位。 对此经常在相应工位上改善导料板边缘和设置更精确的导向装置来解决。另外一种解决边缘卷起的方法是在第一个工位裁去两边的材料。在侧刃处设挡料块作为定距装置以防止材料的过送进。大零件在长的级进模中制造时要有足够大的推力送进带料。但是厚的材料通常较重，也比薄的材料刚度大得多。根据经验可知，运送0.020 英寸到 0.060英寸厚得材料需要3/16 英寸

12、到 5/16 英寸宽的载体。对于厚度高于或低于这个范围的坯料，载体宽度可很容易确定。根据影响模具的各种因素来看，正常情况下载体全长的宽度应当一致，在需要材料移动的特殊区域可以不一致。 大多数的自动送料机构都是以推的形式送料而不是拉料，这就要求载体有足够的强度 。条料送进完成后会出动装在模具出口位置的检测开关。 如果模具打开或闭合时需要载体弯曲而不破裂，且有足够得强度送进零件，载体必须设计得足够长。如果两个弯曲载体强度不够可以考虑设置三个。设计时弯曲半径要尽可能大。 尖角处或者弯曲半径太小的地方载体弯曲时会应力集中会使材料破裂。而且要载体边缘不要有阶梯和断口。压料装置由于体积或功能的需要，很多级

13、进模需要在上模设置两个或三个压料装置。不同工位的压料装置的工作行程可能都不相同，如冲裁或成形和拉深然而，压料装置经常要通过作用在带料上使顶料销下沉。 在这种情况下， 所有压料装置的移动距离必须相同。 如果工作行程不相同， 则有些位置条料不会被完全压住，会使附近的零件离开原来位置，送进时条料定位变得困难。如果要求在零件翻边， 零件载体必须有一个伸缩回路， 以便零件移动或者使凸模 / 压边圈拥有和其他压边装置一样的行程。而凸模或压边圈在极限位置时要有足够的力完成翻边兰。在这过程中条料相应部分的材料垂直流动。当条料下降到工作位置， 施压凸模或压边圈停止向下运动，而上模继续向下冲孔，切边，向下翻边或其

14、他成形操作。 可用强力弹簧或气瓶作为冲压凸模和压边圈的动力源，但要保证它们要有足够的预紧力以完成翻边或在凸模与压边圈后退前压住下模顶料装置。拉深壳体壳体拉深是将板料拉深成圆柱瓶形零件。 在拉深操作中， 坯料直径受壳体周长的影响。而周长又受到材料的流动性和外围材料向内流动阻力和边缘阻力。当边缘材料受到的阻力超过极限值后边缘就会起皱失稳。为了避免出现起皱，必须时材料可以在凸模和压边圈之间顺利流动。 造成拉深破裂的两个主意原因是拉深件直径与坯料直径比值超过极限值和拉深半径太小。从平整的坯料拉深成壳体和将壳体拉深为直径更小的壳体时材料向内流动距离都有一个极限值， 通常称之为拉深系数。 极限拉深系数受到

15、材料流动性、 材料抗压能力和由受压而引起的流动阻力等因素的影响。 过大的流动阻力使壳体边缘破坏起皱，该区域是材料抵抗力最弱的区域。厚度不同材料的拉深系数也不一样。举例来讲，将一坯料进行大深度拉深，第一次拉深直径比值厚度 0.015 英寸的材料是 32，而 0.125 英寸厚的材料是48。对拉深凹模有一最小和最大拉深圆角半径值， 拉深圆角半径直接影响材料的流动性。对深拉深件， 0.015 英寸厚的材料合适的圆角半径是从 5/32 英寸到 1/4 英寸这个范围。 而对于 0.0125 英寸厚的材料， 最小圆角半径不小与 11/32 英寸，最大圆角半径不大于 15/32 英寸。如果圆角半径太小， 金

16、属流动阻力增加， 会造成制件严重变薄或在壳帽边缘破裂，不能很好地拉深成形。 而如果半径太大， 金属一离开凹模与压边圈的接触点还没形成直壁就开始起皱。人们经常是将半径做得小一些 , 因为在试模期间将圆角半径从小改为较大值比较容易，而把较大得圆角半径改小困难得多。 结果造成在杯形边缘应力集中过大，制件变薄严重或破裂。 很多时候采用不适当得拉深百分比或不合适得圆角半径在第一次拉深时看不出来，但在后续工位中要花很多时间去调整。原文一：Improving Performance of Progressive DiesProgressive die stamping is a cost-effective

17、 and safe method of producing components. Careful design and construction of dies will ensure optimum performance.A progressive die performs a series of fundamental sheet metal operations at two or more stations in the die during each press stroke. These simultaneous operations produce a part from a

18、 strip of material that moves through the die. Each working station performs one or more die operations, but the strip must move from the first station through each succeeding station to produce a complete part. Carriers, consisting of one or more strips of material left between the parts, provide m

19、ovement of the parts from one die station to the next. These carrier strips are separated from the parts in the last die station.There are six elements that should be addressed when designing and building a progressive die to maximize its performance:Interpreting the part print,Starting material int

20、o the die,Part lifters and part feeding,Flexible part carriers,Upper pressure pads, andDrawn shells.Interpreting the Part PrintThe first step in the proper design of a progressive die is to correctly analyze the part print. The tool designer must interpret the print to determine the function of the

21、part by looking for such things as the type of material, critical surfaces, hole size and location, burr location, grain direction requirements, surface finish and other factors.The die designer must understand the part well, particularly if it has irregular shapes and contours. However, modern comp

22、uter-drawn prints make this more difficult because computer-drawn part data can be downloaded directly to the die-design computer. As a result, the designer may not become thoroughly familiar with important part features.Also, many computer-drawn parts are more difficult to understand, because often

23、, only one surface is shown and it may be the inside or outside surface. Computerdrawings often show all lines, including hidden features, as solid lines instead of dotted lines. This leads to interpretation errors, which in turn leads to errors in the building of the die.To better understand comple

24、x part shapes, it is helpful to build a "sight" model of the part using sheet wax, rubber skins or wood models. Dimensional accuracy is not critical for these models, as they are used primarily to visualize the part. Rubber skins and sheet wax also can be used to develop preform shapes and

25、 to develop the best positions for the part as it passes through each die operation in the progressive die.Starting Material in the DieCare must be taken to ensure that the strip is started correctly into the die. Improper location of the lead end of the strip will do more damage to the die in the f

26、irst 10 strokes of the press than the next 100,000 strokes. "Lead-in" gauges must have large leads and a ledge to support the lead end of the coil strip when it is inserted into the die. Large leads on the gauges are important so that the die setup person does not have to reach into the di

27、e, as well as for minimizing the time required to start a new stripinto the die. Also, one gauge should be adjustable to compensate for variation in strip width,.The position of the lead edge of the strip is critical for the first press stroke, and must be determined for every die station to ensure

28、that piercing punches do not cut partial holes in the lead edge. This could cause punch deflection or result in a partial cut with trimming punches, which can result in an unbalanced side load as the strip passes through the die. Any of these conditions can result in a shift of the punch-to-die rela

29、tionship that may cause shearing of the punches.Improper location of the lead edge of the strip also can result in an unbalanced forming or flanging condition that can shift the upper die in relation to the lower die. Heels should be required to absorb this side load, particularly when forming thick

30、 materials.A pitch notch and pitch stop can provide a physical point to locate and control the lead edge of the strip. Brass tags or marker grooves also can provide a visual location, but these are not as accurate or as effective as a pitch notch stop. The press can be prevented from operating with

31、either a short feed or over feed by mounting the pitch stop on a pivot and monitoring it with a limit switch.Part Lifters and Part FeedingProgressive dies often require the strip to be lifted from the normal die work level to the feed level before strip feeding takes place. This can vary from a smal

32、l amount-to clear trim and punching burrs-to several inches to allow part shapes to clear the die.Normally, all lifters should rise to the same height so that the strip is supported in alevel plane during forward feed. The strip must not sag between lifters; otherwiseparts will be pulled out of thei

33、r correct station location spacing. Bar lifters providegood support and are better than spring pins or round lifters notched on one side of thestrip.Often, a good bar lifter system allows higher press speeds because feed problems are eliminated. Although the initial cost is more than round lifters,

34、performance is better and setup time is reduced.As the strip is started into the lead-in gauges, the strip should be able to feed automatically through all the following die stations without requiring manual alignment in each set of gauges and lifters. The strip also must be balanced on the lifters

35、so that it does not fall to one side during feed. A retainer cap can be mounted on the top of the outside bar lifters. This produces a groove that captures the strip during feed and prevents strip buckling.Gauging and lifter conditions can be simulated during die design by cutting a piece of transpa

36、rent paper to the width of the strip. The lead edge of the paper is placed over the plan view of the die design at the location the strip will be for the first press stroke. Then the paper is marked with all of the operations that will be performed at the first die station-for example, notching and

37、punching. The paper strip then is moved to the second station on the drawing and the operations for both the first and second stations are marked. This process is repeated through all the die stations to illustrate what the real part strip will look like when it is started into the die and helps det

38、ermine the adequacy of gauges and lifters.To transport the strip from one station to the next in a progressive die, some material must be left between the parts on the strip. This carrier material may be solid across the width of the strip, or may be one or more narrow ribbons of material, see part

39、carriers sidebar.Many parts require the edge of the blank to flow inward during flanging, forming or drawing operations. This may require the carrier to move sideways or flex vertically, or both, during the die operation. A flexible loop must be provided in the carrier to allow flexing and movement

40、of the blank without pulling the adjacent parts out of position, Fig. 2.Another concern is the vertical "breathing" of parts in die stations during the closingand opening of the die in the press stroke. For example, vertical breathing takes placebetween the draw stations of parts requiring

41、 more than one draw to complete the part,Fig. 3. Vertical breathing also occurs when a flange is formed "up" in a progressivedie station that is adjacent to stations that use upper pressure pads to hold the adjacentparts down.It is important to consider the flexing of the carrier during th

42、e upstroke of the press as well as during the downstroke because the action may be different. This can be simulated in the design stage by making an outline of the cross-section of the part, the pressure pads and the stationary-mounted steels on separate sheets of paper and then placing these sheets

43、 on top of each other in layers over the die section views. This will show the relative position of the part as the die closes and during the reverse action as the die ram opensPart CarriersA common feature in all progressive stamping dies is the material that transports the parts from station-to-st

44、ation as it passes through the die. This material is known by various terms, such as carrier, web, strip, tie, attachment, etc. In this instance, we will use the term carrier, of which there are five basic styles:Solid carrier-All required work can be accomplished on the part without preliminary tri

45、mming. The part is cut off or blanked in the final operation.Center carrier-The periphery of the part is trimmed; leaving only a narrow tie near the middle of the part. This permits work to be performed all around the part. A wide center carrier permits trimming only at the sides of the part.Lance a

46、nd carry at the center-The strip is lanced between parts, leaving a narrow area near the center to carry the parts. This eliminates scrap material between parts.Outside carriers-The carriers are attached to the sides of the part so that work can be done to the center of the part.One side carrier-The

47、 part is carried all the way or part of the way through the die with the carrier on one side only. This permits work on three sides of the part. The type or shape of the carrier will vary depending on what the part requires as it progresses from station to station in the die. The stock width may be

48、left solid if no part material motion is required during die closure or it can be notched to create one, two or even three carriers between the partsThe carriers can be straight, form a zig-zag pattern or have loops between the parts depending on where attachment points to the part are available or

49、to accommodate whatever clearance may be required by the die tooling. As the part is formed, flanged or drawn into a shell, the carrier may have to move sideways or up and down as the die closes and opens.When die operations cause the carrier to move, it usually will be required to flex or stretch.

50、Regardless of carrier flexing, their key function is to move the parts close enough to the next station so that pilots, gauges and locators can put the parts into their precise location as the die closes.If the carrier acquires a permanent stretch, the parts may progress too far to fit on the next s

51、tation, or in the case that the die has two carriers, one carrier may develop permanent stretch with no stretch in the other carrier. This will create edge camber in the strip, causing it to veer to one side. This results in poor part location.A stretched carrier can be shortened to its correct leng

52、th by putting a dimple in the carrier. If a center carrier or one-sided carrier develops camber, the strip can be straightened by dimpling or scoring one side of the carrier. Construct the dimple and scoring punches so that they are easily adjusted sideways for position and vertically for depth.as i

53、t is delivered from the coil can cause the strip to bind in the running gauges that guide the material during the feed cycle. This binding may cause the carriers to buckle, which results in short feeds. It often helps to relieve the guide edge of the gauges in between stations and have tighter gauge

54、 control at the work station.Another option is to eliminate camber by trimming both sides of the material in the beginning of the die. By adding stops at the end of these trim notches they can be used as pitch control notches to prevent progression overfeed.Optimum Carrier ProfileThe optimum carrier

55、 profile is affected by some of the following conditions:Space available between parts: Try to keep the carriers within the stock width and pitch required for the blank. If this is not possible then the designer must add to the width and/or the progression of the material to provide adequate carrier

56、 room.Attachment points to the part: If two carriers are used, try to keep the profile and length of the carriers somewhat the same so that any effect of carrier flexing is close to being balanced.Clearance for punch and die blocks: Punch blocks that extend below the stock or die blocks that extend above the stock when the die closes will require clearance in relation to the parts and the carriers. If a loop of the carrier interferes with blocks it may be possible to form the loop vertical to provide clearance.Thickness of the material: Large parts with thin material may require stiffener bea