四垫圈冲孔、落料复合模设计【多垫圈】【说明书+CAD】
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General all-steel punching dies punching accuracy Author:John J. Craig Accuracy of panel punching part is display the press accuracy of the die exactly. But the accuracy of any punching parts linear dimension and positional accuracy almost depend on the blanking and blanking accuracy,. So that the compound mould of compound punchings accuracy, is typicalness and representation in the majority.Analyse of the dies accuracy For the analyse of pracyicable inaccuracy during production of dies to inactivation, we could get the tendency when it is augmentation in most time. From this we could analyse the elements. When the new punch dies pt into production to the first cutter grinding, the inaccuracy produced called initial error; if the die grinding more than twenty times, until its discard, the inaccuracy called conventional error; and before the dies discard, the largest error of the last batch permit, called limiting error. at job site, the evidence to confirm life of sharpening is the higher of the blanking, punched hole or punched parts. Because all finished parts had been blanked ,so it is especially for the compound dies. Therefore, the analyse of burr and measurement is especially important when do them as enterprise standardization or checked with . The initial error usually is the minimal through the whole life of die. Its magnitude depend on the accuracy of manufacture, quality, measure of the punching part, thickness of panel, magnitude of gap and degree of homogeneity. The accuracy of manufacture depend on the manufacture process. For the 1 mm thicked compound punching part made in medium steel, the experimental result and productive practice all prove that the burr of dies which produced by spark cutting are higher 25%30% than produced by grinder ,NC or CNC. The reason is that not only the latter have more exact machining accuracy but also the value of roughness Ra is less one order than the formmer, it can be reached 0.025m. Therefore, the dies initial blanked accuracy depends on the accuracy of manufacture, quality and so on. The normal error of the punch die is the practicable error when the fist cutter grinding and the last cutter grinding before the die produce the last qualified product. As the increase of cutter grinding, caused the measure the nature wear of the dies are gradual increasing, the error of punching part increase also, so the parts are blew proof. And the die will be unused. The hole on the part and inner because the measure of wear will be small and small gradually, and its outside form will be lager in the same reason. Therefore, the hole and inner form in the part will be made mould according to one-way positive deviation or nearly equal to the limit max measure. In like manner, the punching parts appearance will be made mould according to one-way negative deviation or nearly equal to limit mini measure. For this will be broaden the normal error, and the cutter grinding times will be increased, the life will be long. The limit error in punching parts are the max dimension error which practicable allowed in the parts with limit error. This kind of parts usually are the last qualified products before the die discard. For the all classes of dies, if we analyse the fluctuate, tendency of increase and decrease and law which appeared in the dies whole life, we will find that the master of the error are changeless; the error that because the abrade of the cutter and impression will be as the cutter grinding times increased at the same time. And that will cause the error oversize gradually; and also have another part error are unconventional , unforeseen. Therefore, every die s error are composed of fixed error, system error, accident error and so on. At the whole process when the New punching die between just input production to discard, the changeless master error that in qualified part are called fixed error. Its magnitude is the deviation when the die production qualified products before the first cutter grinding. Also is the initial error, but the die have initial punching accuracy at this time. Because of the abrade of parts, the die after grinding will be change the dimension error. And the increment of deviation will oversize as the times of cutter grinding. So the punching accuracy after cutter grinding also called “grinding accuracy” and lower tan initial accuracy. The fixed error depend on the elements factor as followed :1. the material , sorts, structure, (form) dimension, and thick of panel the magnitude of punching gap and degree of homogeneity are have a important effect for the dimension accuracy. Different punching process, material, thick of panel, have completely different gap and punching accuracy. A gear H62 which made in yellow brass with the same mode number m=0.34, 2mm thick and had a center hole, when the gap get C=0.5%t (single edge) , and punched with compound punching die, and the dimension accuracy reached IT7, the part have a flat surface ,the verticality of tangent plane reached 89.5, its roughness Ra magnitude are 12.5m, height of burr are 0.10mm; and the punching part are punched with progressive die, the gap C=7%t (single edge) , initial accuracy are IT11, and have an more rough surface, even can see the gap with eyes. In the usual situation, flushes a material and its thickness t is theselection punching gap main basis. Once the designation gap haddetermined flushes the plane size the fixed error main body; Flushesthe structure rigidity and the three-dimensional shape affects itsshape position precision.2. punching craft and molder structure type Uses the different ramming craft, flushes a precision and the fixederror difference is really big. Except that the above piece gearexample showed, the essence flushes the craft and ordinary punching flushes a precision and the fixed error differs outside a magnitude,even if in ordinary punching center, uses the different gap punching, thefixed error difference very is also big. For example material thickt=1.5mm H62 brass punching, selects C = the 40%t unilateral I kind ofsmall gap punching compared to select C 4mm flushes, the size precision can lower some. Different dies structure type, because is suitable the rammingmaterial to be thick and the manufacture precision difference, causesto flush a fixed error to have leaves. Compound die center, multi-locations continuous type compound die because flushes continuously toduplicate the localization to add on the pattern making error to bebigger, therefore it flushes a fixed error compound punching die to wantcompared to the single location Big 1 2 levels 3. the craft of punching dies manufacture the main work of punching die namely are raised, the concave moldprocessing procedure, to operates on the specification not to behigh, can time form a more complex cavity. But its processing surfaceapproximately is thick 0.03 0.05mm is the high temperatureablation remaining furcated austenite organization, degree ofhardness may reach as high as HRC67 70, has the micro crack, easilywhen punching appears broke the cutter or flaking. The Italian CorradaCorporations related memoir called the line cut the processing contruction to have the disadvantageous influence to the superficialgold, in fact already changed the gold contruction. We must use theJingang stone powder to grind or the numerical control continual pathcoordinates rub truncate (cut to line) to make the precision work . In recent years country and so on Switzerland and Japan, has conductedthe thorough research to the electrical finishing equipment and abigger improvement, makes function complete high accuracy NC and theCNC line cutter, the processing precision may reach 0.005 0.001mm,even is smaller. The processing surface roughness Ra value can achieve0.4 mu m. According to the recent years to the domestic 12 productionlines cutter factory investigation and study, the domesticallyproduced line cutter processing precision different factory differentmodel line cutter might reach 0.008 0.005mm, generally all in0.01mm or bigger somewhat, was individual also can achieve0.005mm, the processing surface roughness Ra value was bigger than1.6m. However, the electrical finishing ablation metal surface thus the change and the damage machined surface mental structure character can not change, only if with rubs truncates or other ways removes this harmful level. Therefore, merely uses electricity machining, including the spark cutting and the electricity perforation, achieves with difficulty punching, especially high accuracy, high life punching die to size precision and work components surface roughness Ra value request. With precisely rubs truncates the law manufacture punching die, specially makes the high accuracy, the high life punching die, such as: Thin material small gap compound punching die, multi- locations continuous type compound die and so on, has the size precision high, the work component smachined surface roughness Ra value is small, the mold life higher characteristic. Its processing craft at present changed the electrical fire by the past ordinary engine bed rough machining spark cutting or the electricity puncher rough machining, finally precisely rubs truncates, also from takes shape rubs, optics curve rubs, the manual grid reference rubs gradually filters the continual path grid reference to rub and NC and the CNC continual path grid reference rubs, Processing coarseness may reach 0.001 0.0005mm, the processing surface roughness Ra value may reach 0.1 0.025 mu m. Therefore, with this craft manufacture the die , regardless of the size precision, the work components surface roughness, all can satisfy die, each kind of compound request, the die is especially higher than the electrical finishing craft manufacture scale.4. gap size and degree of homogeneity the flange and other sheet forming sgene rally all must first punching (fall material) the plate to launch the semi finished materials, after also has the forming to fall the material, the incision obtains the single end product to flush. Therefore punching the work, including is commonly used punching hole, the margin, cut side and so on, regarding each kind of sheet pressing partall is necessary. Therefore punching the gap to flushes a out form in chprecision to have the decisive influence. punching the gap small and is even, may cause punching the size gain high accuracy. Regarding drawability, is curving and so on mould, the gap greatly will decide increases flushes the oral area size error and the snapping back. The gapnon-uniformity can cause to flush a burr enlarges and incurs cutting edge the non-uniform attrition. 5. ramming equipment elastic deformation In the ramming process After the punch press load bearing can have the certain elastic deformation. Although this kind of distortion quantity according to flushes the pressure the size to change also to have the obvious directivity, but on the pressing part, mainly is to has the volume ramming archery target stamping, embosses, the equalization, the pressure is raised, the wave, flushes crowds, the shape, the flange, hits flatly, thinly changes draw ability and so on the craft work punching forming flushes, has the significant influence to its ramming aspect size precision From: 黄河科技学院毕业设计(文献翻译) 第 4 页 普通全钢冲模的冲压精度 作者:约翰J克雷格 板料冲压件的精度准确显示出其冲模的冲压精度。而任何冲件的线性尺寸精度与形位精度主要取决于冲模冲裁和立体成形冲压件展开平毛坯的落料精度。因此,多工步复合冲压的单工位复合模、多工位连续模的冲压精度,在普通冲压的众多种类与不同结构的冲模中,最具典型性和代表性。冲模的冲压精度分析 对冲模投产至失效报废各个时期冲件的实际误差分析,可以看出其增大的时期及趋向,从而分析其增大的因素。新冲模投产至第一次刃磨前冲制冲件的误差即所谓的初始误差;冲模经过20次左右刃磨至失效报废前冲制的冲件误差称之为常规误差;而冲模失效报废前冲制的最后一批合格冲件的允许最大误差称之为极限误差。在现场,确定冲模刃磨寿命的依据是冲件冲孔与落料的毛刺高度。由于任何成形件都具有冲裁作业(毛坯落料或冲孔),对于复合模尤为如此。所以,冲件毛刺高度的触模检查和测量并按企业标准或JB4129-85冲压件毛刺高度对照检测就显得十分重要。 冲模的初始误差通常是冲模整个寿命中冲件误差最小的。其大小主要取决于冲模的制造精度与质量及冲件尺寸、料厚以及间隙值大小与均匀度。冲模的制造精度及质量又取决于制模工艺。对于料厚t1mm的中碳钢复合冲裁模冲件,实验结果与生产实践都证明,电火花线切割制造的冲模冲件毛刺高度比用成型磨或NC与CNC连续轨迹座标磨即精密磨削工艺制造的冲模冲件要高25%30%。这是因为后者不仅加工精度高,而且加工面粗糙度Ra值要比前者小一个数量级,可达到0.025m。因此,冲模的制造精度与质量等因素决定了冲模的初始冲压精度,也造就了冲件的初始误差。 冲件的常规误差是冲模经第一次刃磨到最后一次刃磨后冲出最后一个合格冲件为止,冲件实际具有的误差。随着刃磨次数的增加,刃口的自然磨损而造成的尺寸增量逐渐加大,冲件的误差也随之加大。当其误差超过极限偏差时,冲件就不合格,冲模也就失效报废。冲件上孔与内形因凸模磨损尺寸会逐渐变小;其外形落料尺寸会因凹模磨损而逐渐增大。所以,冲件上孔与内形按单向正偏差标允差并依接近或几乎等于极限最大尺寸制模。同理,冲件外形落料按单向负偏差标注允差并依接近或几乎等于极限最小尺寸制模。这样就使冲件的常规误差范围扩大,冲模可刃磨次数增加,模具寿命提高。 冲件的极限误差是具有极限偏差的冲件所具有的实际允许的最大尺寸误差。这类冲件通常是在冲模失效报废前冲制的最后一批合格冲件。 对各类冲模冲件误差在冲模整个寿命中出现的波动、增减趋向及规律等进行全面分析便可发现:冲件误差的主导部分是不变的;因刃口或型腔的自然磨损而出现的误差增量随冲模刃磨冲数增加而使这部分误差逐渐加大;还有部分误差的增量是非常规的、不可预见的。所以,各类冲模冲件误差是由因定误差、渐增误差、系统误差及偶发误差等几部分综合构成。 新冲模在指定的冲压设备上投入使用至失效报废的整个(总)寿命过程中,其合格冲件误差的主导部分固定不变即所谓固定误差。其大小就是新冲模第一次刃磨前冲制的合格冲件的偏差,也即冲模的初始误差,而此时的冲模具有初始冲压精度。刃磨后的冲模,因其工作零件(凸、凹模)磨损而改变尺寸误差,使冲件识差增量随刃磨次数增加而逐渐加大,故冲模刃磨后的冲压精度亦称“刃磨精度”比其初始精度要低。冲模冲件的固定误差取决于以下各要素:1、冲件的材料种类、结构(形状)尺寸及料厚 冲裁间隙的大小及其均匀度对冲裁件的尺寸精度有决定性的影响。不同冲裁工艺、不同材料种类与不等料厚,间隙相差悬殊,冲压精度差异很大。同一种模数m=0.34的2mm的料厚、中心有孔的H62黄铜材料片齿轮复合模冲件,当取间隙C=0.5%t(单边),用复合精冲模冲制,冲件尺寸精度达到IT7级,冲件平直无拱弯,冲切面垂直度可达89.5,其表面粗糙Ra值为0.2m;而用普通复合模冲制,间隙C=5%t(单边),冲件初始误差亦即冲模的初始冲压精度为1T9级,冲切面粗糙度Ra值为12.5m,毛刺高度为0.10mm;还是这个冲件用连续模冲制,间隙C=7%t(单边),初始冲件精度为IT11级,冲切面更粗糙,甚至有肉眼可见的台阶。通常情况下,冲件材料及其厚度t是选取冲裁间隙的主要依据。一旦选定间隙就确定了冲件的平面尺寸的固定误差的主体;冲件结构刚度及立体形状则影响其形位精度。2、冲压工艺及冲模结构类型 采用不同的冲压工艺,冲件的精度及固定误差相差甚大。除上述片齿轮实例说明,精冲工艺与普通冲裁的冲件精度与固定误差相差一个数量级之外,即便在普通冲裁中,采用不同间隙冲裁,固定误差相差也很大。例如料厚t=1.5mm的H62黄铜冲裁件,选用C40%t单边类小间隙冲裁比选用C8%t(单边)类大间隙冲裁,冲件固定误差将加大40%60%,精度至少降一级。此外,采有无搭边排样,冲件的误差要远大于有搭边排样冲件。无搭边排样冲件。无搭边排样冲件的精度低于IT12级,而多数有搭边排样的冲件精度在IT11IT9级之间,料厚t4mm的冲件,尺寸精度会更低一些。 不同冲模结构类型,由于适用冲压料厚及制造精度的差异,导致冲件的固定误差有别。复合模中,多工位连续式复合模由于冲件连续重复定位加上制模误差较大,故其冲件的固定误差比单工位复合冲裁模要 大12级。3、冲模制造工艺 冲模主要工作零件即凸、凹模的加工程序,对操作上的技术要求不高,能够一次成形较复杂的模腔。但其加工表面约厚0.030.05mm为高温烧蚀的残余树枝状奥氏体组织,硬度可高达HRC6770,有显微裂纹,容易在冲裁时出现崩刃或剥落。意大利Corrada公司的有关研究报告称“线切割加工对表面金相结构产生不利的影响,实际上已经改变了金相结构。我们必须用金刚石粉研磨或数控连续轨迹坐标磨削(对线切割件)作精加工”。近年来瑞士和日本等国,对电加工设备进行了深入的研究和较大的改进,制造出功能齐全的高精度NC和CNC线切割机,加工精度可达0.0050.001mm,甚至更小。加工表面粗糙度Ra值能达到0.4m。根据近年对国内12家生产线切割机工厂的调研,国产线切割机加工精度各别厂家的各别型号线切割机可达0.0080.005mm,一般都在0.01mm或更大一些,个别也能达到0.005mm,加工表面粗糙度Ra值均大于1.6m。然而,电加工烧蚀金属表面从而改变和损坏加工面金相结构的特性不会改变,除非用磨削或其他加工法去除这一有害层。所以,仅仅用电加工法,包括电火花线切割与电穿孔,难以达到冲模,尤其高精度、高寿命冲模对尺寸精度与工作零件表面粗糙度Ra值要求。 用精密磨削法制造冲模,特别是制造高精度、高寿命冲模,诸如:薄料小间隙复合冲裁模、多工位连续式复合模等,具有尺寸精度高、工作零件加工面粗糙度Ra值小、模具寿命高等特点。其加工工艺目前已由过去的普通机床粗加工改为电火花线切割或电穿孔机粗加工,最后精密磨削,也由成型磨、光学曲线磨、手动座标磨逐步过滤到连续轨迹座标磨及NC与CNC连续轨迹座标磨,加工粗度可达0.0010.0005mm,加工表面粗糙度Ra值可达0.10.025m。所以,用该工艺制造的冲模,无论尺寸精度、工作零件表面粗糙度,都能满足冲模,尤其各种复合模的要求,比电加工工艺制造的冲模高一个档次。4、间隙的大小与均匀度 拉深、弯曲、翻边及其他板料成形件一般都要先冲裁(落料)出平板展开毛坯,也有成形后落料、切开得到单个成品冲件。故冲裁作业,包括常用的冲孔、切口、切边等,对于每种板料冲压件都是必要的。所以冲裁间隙对冲件的外廓尺寸精度有决定性的影响。冲裁间隙小而均匀,可使冲裁尺寸获取更高精度。对于拉深、弯曲等成形模,间隙大定将增大冲件口部尺寸误差及回弹。间隙不均匀会使冲件毛刺加大并招致刃口的不均匀磨损。5、冲压设备的弹性变形 在冲压过程中,冲床承载后会产生一定的弹性变形。虽然这种变形量依冲压力的大小变化且具有明显的方向性,但就冲压件,主要是对具有体积冲压性质的压印、压花、校平、压凸、起波、冲挤、镦形、翻边、镦粗、打扁、变薄拉深等工艺作业冲制成形的冲件,对其冲压方面的尺寸精度有重大影响。 出自:科学指南 毕业设计文献翻译 院(系)名称工学院机械系 专业名称机械设计制造及其自动化 学生姓名郭中亮 指导教师 康红伟2012年 03 月 10 日目录一、设计多垫圈复合模的出发点 2二、多垫圈复合模冲压的工艺分析 41、材料42、尺寸精度43、冲压工艺分析4三、冲压工艺方案的制定 61、单垫圈、多垫圈复合模的比较62、主要难题及解决方法6四、冲压工艺的计算 8(一)、排样计算8(二)、计算各工序压力、选择压力机10(三)、复合模的凸、凹模的计算111、凸、凹模的刃口计算112、凸凹模的设计13(四)、弹簧的选用和计算14五、选择压力机型号 16六、主要零部件结构与尺寸的选择和确定 17七、绘制模具总装图 21八、绘制主要非标准零部件图 23九、结束语 24参考文献 25一、设计多垫圈复合模的出发点因冷冲压能得到形状较复杂的制件,且加工精度高,尺寸稳定,互换性好,在大量生产条件下,制件成本低,生产效率高,易于自动化。所以随着我国工业的现代化,冷冲压工艺正越来越多地被采用,并在使用中得到不断发展。在冲压生产中,冲裁所使用的模具称为冲裁模。它是冲压生产中不可缺少的工艺设备,良好的模具结构是实现工艺方案的可靠保证。常用的冲裁模典型结构主要有单工序冲裁模、复合模、连续模。由这次毕业设计的题目多垫圈复合模可知需要设计一付加工垫圈的模具。垫圈常用于各种仪器仪表,更可起到防震、绝缘的作用,且年产量高。考虑到单工序冲裁生产效率低、难以满足该零件的年产量要求,故考虑采用复合冲裁与连续冲裁。复合冲裁是冲床在一次行程中,板料在冲模内经过一次定位,能够同时完成两种或两种以上不同工序的冲压过程。对于该零件采用复合模能保证冲压件的形位精度和尺寸精度,且生产效率也高。连续冲裁是在一套冲模里,把同一个冲压件的几个工序排列成一定顺序。加工时,冲床每次行程,条料在冲模里依次移动一个位置。在不同的位置(简称工位)上,分别进行工件所要求的不同工步(即连续冲压工序中每一单独的工序),除最初几次冲程外,以后每次冲程都可以完成一个冲压件。对于该零件采用连续冲裁虽能满足其生产效率,但零件的材料为橡胶,质软,采用连续冲裁难以保证冲压件的形位精度和尺寸精度,而且其模具制造、安装较复合模要复杂。通过对单工序模、复合模、连续模的比较分析,决定采用复合模形式比较合适。而这次毕业设计的任务是设计出一付能一次冲出多个垫圈的复合模,其主要是因为某厂生产的垫圈用处广泛,规格繁多,每年的垫圈单件产量多在百万以上。由于厂家竞争激烈,产品面临着残酷的考验。为此,必须在内部通过优化加工工艺,提高材料利用率、生产效率等来降低成本。首先,在指导老师的建议下,将各种垫圈的规格大小进行了分类比较。然后设想能否在单冲垫圈的基础上,一模同时冲压出多个各种规格的产品。以达到既能提高工作效率,又能提高材料的利用率。在查阅了大量的文献资料后,初步掌握了模具的设计方法,由于时间仓促,水平有限,整个设计必然有许多不足之处,这有待于今后在工作、学习中的不断更正和改进。 二、多垫圈复合模冲压的工艺分析1、 材料:该零件的材料为人造橡胶,厚度为2mm,年产量百万以上。常用于各种仪表、仪器等。2、 尺寸精度:因为材料性质,所取的凸凹模的间隙应偏小,故模具零件的加工精度较高。所以可以初定最大外圆尺寸500-0.1mm、及最小内孔尺寸120+0.070均为IT10级。3、 冲压工艺性分析:在排列出的各种规格垫圈中,在最不影响产品质量情况下及在符合产品所允许的公差范围里,选出厚度一样(均为2mm)、材料相同的垫圈,将其内外结构、尺寸进行整理如图所示: 原垫圈的尺寸 调整后的垫圈尺寸 从图中可以看出,尺寸经过调整后,垫圈的内外圈关系正好是相互套裁的。 垫圈甲(外径为50)的孔径为垫圈乙(外径36)的外径,垫圈乙的孔径为垫圈丙(外径26)的外径,垫圈丙的孔径为垫圈丁(外径16)的外径。这正符合一模同时冲压下四个垫圈的条件。从其普遍的垫圈性质和客户的要求来说,略作尺寸改动并不影响产品的使用,也不影响产品的质量。所以如果将原来的一次冲一模改进为一次冲出四模,不仅可使材料的利用率成倍的提高,生产效率更能大幅度地提高四倍。并节省了人工、电耗等。经济效益十分可观。三、 冲压工艺方案的制定1、 方案的制定:冲压垫圈工序较简单,基本工序是冲孔、落料。 比较项目单垫圈复合模多垫圈复合模 材料的利用率K=31%K=61%每一次冲得产品1件4件产品质量佳佳调整单件批量容易不易模具开制成本估价2000元/付4=8000元8000元/付模具寿命长长模具维护简单较难冲压操作简单简单该厂原来都是以单垫圈形式开制的复合模,现在多以用多垫圈复合模。为了更清晰了解这两种复合模冲压成型产品的优劣性,下面列表将它们进行比较:从上述列表中可以看出,多垫圈复合模在关键两项材料利用率和生产效率的对比上遥遥领先于单垫圈复合模。从某种意义上来讲,该模具满足了单件产品需求量巨大的情况。同时使本厂的竞争力大大提高。所以,采用多垫圈复合模冲制零件。2、 主要难题及解决方法。(1) 主要难题:由于该零件的结构简单,整个冲制过程并不存在什么问题。但是该复合模由多付凸凹模组合而成,所以如何将凸凹模中的产品一次卸出来成为一个主要难题。(2) 解决方法:如下图所示是凸凹模与卸料板的关系。 图1 图2 由图1、2中可看出,凸凹模是尾部相互固定组合而成。而卸料板也必须与其同步而行,一起动作,才能成功卸料。所以,需要在组合凸凹模上以穿孔机穿孔,然后经由线切割割出腰圆长槽,用销子8将卸料圈串合起来。就能成功使卸料板、凸凹模成为一体在腰圆槽里上下同时动作,以达到一次将冲压的四片垫圈卸出来的目的。四、 冲压工艺的计算模具设计,牵涉面广,要了解模具的加工工艺,不然设计出的模具无法加工就失败了。首先要确定凸凹模的间隙,冲裁模凸模的横断面一般都小于凹模孔。凸凹模之间应有适当的空隙,但间隙的大小牵涉范围很多。间隙过小时,会使冲裁后的落料件尺寸增大,冲孔件尺寸缩小;间隙过大时,会使冲裁结束后的落料件尺寸缩小,冲孔件尺寸增大。间隙大小还对模具寿命有影响。当间隙增大时,模具寿命有明显增长。同时,间隙的大小还和工件平直、冲裁面毛刺大小等密切相关。故应考虑垫片的产品性质,主要要求为:产品要平直、无毛刺。产品材料为人造橡胶,适宜选偏小间隙,查表后可确定其双边间隙为0.08mm。其次,要计算凸、凹模的尺寸大小、冲裁件的排样方式和了解被加工零件的冲裁力、卸料力、推料力等,还要根据计算出来的冲压力选择压力机。了解该压力机的开闭合高度,安装板的大小等,才能考虑模具的总厚度是多少并确定模架。根据冲压零件的材料、批量来定模具凸凹模的材料,淬火硬度等。(一)、排样计算为了合理利用材料,并尽可能的节省材料,应对冲裁件进行合理地排样。1、板料规格的确定:零件材料为人造橡胶,厚度为2mm,选用2mm500mm500mm。2、方案的确定:方案一:采用单排法1)查表得搭边值 a=2mm,a1=1.5mm 则B=D2a=5022=54mm2)确定步距ss=Da1=501.5=51.5mm3)裁板条数n1=Bb/B=500/54=9条,余14mm;每条冲零件个数n2=(Lba1)/s=(5001.5)/51.5=9个,余35mm;每板冲零件总个数n总=n1n2=99=81个板料的利用率为总=n总(R2r2)/LbBb100%=813.14(25262)/500500100%=60%方案二:采用多排。1)如图所示,根据相关几何知识可知B=D2a=(501.5)sin605022=44.6504=98.6mm2)步距s=Da1=501.5=51.5mm3)裁板条数n1=Bb/B =500/98.6=5条,余7mm; 每条冲零件个数n2=(Lba1)/s=(5001.5)/51.5=9个余35mm; 每板冲零件总个数n总=2n1n2=90个 板料利用率为总=n总(R2r2)/LbBb100%=903.14(25262)/500500100% =66.6%由上述可知,采用单排的板料利用率为60%,采用多排的板料利用率可提高到66%。很明显,多排方式是能达到提高材料利用率的要求,所以采用多排方式。(二)、计算各工序压力、选择压力机该产品只需冲孔、落料复合冲压一道工序,并根据复合模的结构能一次冲出四个垫圈。已知产品材料为人造橡胶,厚度为2mm,查表得=50N/mm2四垫圈冲裁力P冲=KLt =1.3(5036261612)3.14250 =57148N人造橡胶的K卸系数根据材料性质并查表得K卸=0.01四垫圈卸料力P卸=K卸P冲 =0.0157148 =571.48N同理得,K顶=0.015四垫圈顶料力P顶=K顶P冲 =0.01557148 =857.22N多垫圈复合模结构主要是采用弹性卸料装置和上出料方式的冲裁工艺力,故 P总=P冲P卸P顶 =57148571.48857.22 =58576.7N =58.5767.103N =59KN按现有规格选用100KN压力机比较适宜。但是考虑到模具结构,为了能满足模具最大封闭闭合高度,选用160KN压力机才更适宜。(三)、复合模的凸、凹模刃口计算1、复合模的凸、凹模刃口计算1)冲孔部分:凸凹模中的凹模部分和冲孔凸模部分,可采用分开加工。如图所示,该零件的材料为人造橡胶,厚度t=2mm。属于一般的冲孔、落料件。120+0.070mm由冲孔获得。查双边间隙表得,Zmin=0.0615mm,Zmax=0.09mm则ZmaxZmin=0.090.0615=0.0285mm零件精度IT10以上,=1。按照模具制造精度高于冲裁件精度34级的原则,设凸、凹模按IT5级制造,冲孔120+0.070mm,查表得,凸=凹=0.008mm。d凸=(d)0凸=(12mm10.070)00.008=12.0700.008mmd凹=(dZmin)0凹=(12mm10.0700.0615)0+0.008=12.13150+0.008mm校核:凸凹ZmaxZmin凸凹=0.0080.008=0.016mm0.0285mm故凸、凹模刃口尺寸可确定。根据模具结构要求,可确定凸模以台肩固定的方式固定。因是采用弹性卸料板的小凸模,可确定凸模长度为:L=h1h2h式中L凸模长度h1凸模固定板厚度(20mm)h2卸料板厚度(15mm)材料厚度(2mm)h附加长度,它包括凸模的修模量,凸模进入凹模的深度,凸模固定板与卸料板之间的安全距离。一般取h=1520mm。故总长度L=2015215=52mm 即确定的凸模长度为52mm。详细凸模尺寸见零件图第9页。2)落料部分:圆形落料凹模和凸凹模中的凸模部分,亦采用分开加工。5000.1mm由落料获得。查表得,凹=0.011mm,凸=0.011mm。D凹=(D)0+凹=(5010.1)0+0.011=49.90+0.011mmD凸=(DZmin)0凸=(5010.10.0615) 00.011=49.838500.011mm 校核:凸凹=0.0110.011=0.022mm0.0285mm所以凸、凹模尺寸可确定。该复合模的凹模刃口为直筒形,用螺钉固定在上模座上,因此它属于倒装复合模。根据模具结构要求,确定凹模壁厚为35mm。其实际尺寸可参看零件图第4页。另外,因为该模具的四付凸凹模之间尺寸有互借关系,所以按其名义尺寸进行制造。2、凸、凹模的设计该模具为同时冲出四个垫圈的复合模。这四个垫圈的尺寸是相互套裁的。用复合模冲出四个垫圈(这四个垫圈尺寸按由大到小分别以甲、乙、丙、丁命名),理应在同一位置上要布置八套凸、凹模。由于其中有三个是套裁的,需要五付凸、凹模。这副模具进一步展示了复合模在同一位置布置多套凸、凹模的结构特点。这副模具的凸、凹模的布置方法是:上模部分装有凸凹模2(它的外切刃口是垫圈甲的冲孔凸模同时又是垫圈乙的落料凸模,它的内刃口是垫圈乙的冲孔凹模同时又是垫圈丙的落料凹模)和垫圈甲的落料凹模3、凸凹模18(它的外切刃口是垫圈丙的冲孔凸模同时又是垫圈丁的落料凸模,它的内刃口是垫圈丁的冲孔凹模)。下模部分装有凸凹模7(它的外切刃口是垫圈甲的落料凸模 ,它的内刃口是垫圈甲的冲孔凹模同时又是垫圈乙的落料凹模)和垫圈丁的冲孔凸模11以及凸凹模14(它的外切口是垫圈乙的冲孔凸模同时又是垫圈丙的落料凸模,它的内刃口是垫圈丙的冲孔凹模同时又是垫圈丁的落料凹模)。冲裁后,由上模推下的是垫圈甲、丙,还有垫圈丁的冲孔废料,由下模顶出(在下模座下装有弹顶装置)的是垫圈乙和垫圈丁。关于其卸料方式已在上文中提及,就不再详细介绍。(四)、弹簧的选用和计算1)卸料力前面已算出,总卸料力F卸=571.48N,根据模具结构估计拟选用4个弹簧,计算每个弹簧担负卸料力约为F预=F卸/n =571.48/4 =142.87N即每个弹簧所承受的负荷力为142.87N。2)由装配结构尺寸,求得弹簧自由高度H0凸模固定板厚度弹簧压缩量凸模自由高度H0201.2515=36.25mm根据F预的大小,从圆柱螺旋压缩弹簧表中可初选弹簧规格为外径D=16mm,钢丝直径d=2.5mm,自由高度H0=50mm,弹簧最大工作载荷下的总变形量H许=17.5mm,有效圈数n=9.5,最大工作载荷F许=292N。3)求出弹簧的预压缩量:H预=F预H许/F许 =142.8717.5/292 =8.56mm 则总压缩量为:H总=H预H工作H修磨=8.56215 =16.56mm 总压力F总=F预H总/ H预=142.8716.56/8.56=276.4N4)检查所选弹簧的性能要求,即 总压缩量H总=16.56mm最大许可压缩量H 许=17.5mm 总压力F总=276.4N最大工作负荷F许=292N说明所选弹簧合适最后选弹簧规格为:16mm2.5mm50mm五、 选择压力机型号因为模具闭合高度:H闭=上模座厚下模座厚落料凹模厚冲孔凸模长度上垫板下垫板落料凹模与凸模的刃面高度差板料厚度=40455252101012=210mm根据设备载荷情况和模具的闭合高度,可选用J23-16型
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