【正文】
ctrical 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 monly 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 gapnonuniformity can cause to flush a burr enlarges and incurs cutting edge the nonuniform 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外文譯文普通全鋼沖模的沖壓精度分析沖壓零件的精度是面板顯示媒體模具的精度完全正確。所以復(fù)合模具的復(fù)合沖壓的準(zhǔn)確性在普通沖壓的眾多種類與不同結(jié)構(gòu)的沖模中,最具典型性和代表性。新沖模投產(chǎn)至第一次刃磨前沖制沖件的誤差即所謂的初始誤差;沖模經(jīng)過20次左右刃磨至失效報(bào)廢前沖制的沖件誤差稱之為常規(guī)誤差;而沖模失效報(bào)廢前沖制的最后一批合格沖件的允許最大誤差稱之為極限誤差。由于任何成形件都具有沖裁作業(yè)(毛坯落料或沖孔),對于復(fù)合模尤為如此。沖模的初始誤差通常是沖模整個(gè)壽命中沖件誤差最小的。沖模的制造精度及質(zhì)量又取決于制模工藝。這是因?yàn)楹笳卟粌H加工精度高,而且加工面粗糙度Ra值要比前者小一個(gè)數(shù)量級(jí)。沖件的常規(guī)誤差是沖模經(jīng)第一次刃磨到最后一次刃磨后沖出最后一個(gè)合格沖件為止,沖件實(shí)際具有的誤差。當(dāng)其誤差超過極限偏差時(shí),沖件就不合格,沖模也就失效報(bào)廢。所以,沖件上孔與內(nèi)形按單向正偏差標(biāo)允差并依接近或幾乎等于極限最大尺寸制模。這樣就使沖件的常規(guī)誤差范圍擴(kuò)大,沖模可刃磨次數(shù)增加,模具壽命提高。這類沖件通常是在沖模失效報(bào)廢前沖制的最后一批合格沖件。所以,各類沖模沖件誤差是由因定誤差、漸增誤差、系統(tǒng)誤差及偶發(fā)誤差等幾部分綜合構(gòu)成。其大小就是新沖模第一次刃磨前沖制的合格沖件的偏差,也即沖模的初始誤差,而此時(shí)的沖模具有初始沖壓精度。沖模沖件的固定誤差取決于以下各要素:(1)沖件的材料種類、結(jié)構(gòu)(形狀)尺寸及料厚沖裁間隙的大小及其均勻度對沖裁件的尺寸精度有決定性的影響。同一種模數(shù)m=、中心有孔的H62黃銅材料片齒輪復(fù)合模沖件,當(dāng)取間隙C=%t(單邊),用復(fù)合精沖模沖制,沖件尺寸精度達(dá)到IT7級(jí),沖件平直無拱彎,176。通常情況下,沖件材料及其厚度t是選取沖裁間隙的主要依據(jù)。(2)沖壓工藝及沖模結(jié)構(gòu)類型采用不同的沖壓工藝,沖件的精度及固定誤差相差甚大。例如料厚t=,選用C≤40%t單邊Ⅰ類小間隙沖裁比選用C≤8%t(單邊)Ⅲ類大間隙沖裁,沖件固定誤差將加大40%~60%,精度至少降一級(jí)。無搭邊排樣沖件。不同沖模結(jié)構(gòu)類型,由于適用沖壓料厚及制造精度的差異,導(dǎo)致沖件的固定誤差有別。(3)沖模制造工藝沖模主要工作零件即凸、凹模的加工程序,對操作上的技術(shù)要求不高,能夠一次成形較復(fù)雜的模腔。意大利Corrada公司的有關(guān)研究報(bào)告稱“線切割加工對表面金相結(jié)構(gòu)產(chǎn)生不利的影響,實(shí)際上已經(jīng)改變了金相結(jié)構(gòu)。近年來瑞士和日本等國,對電加工設(shè)備進(jìn)行了深入的研究和較大的改進(jìn),制造出功能齊全的高精度NC和CNC線切割機(jī),加工精度可達(dá)177。根據(jù)近年對國內(nèi)12家生產(chǎn)線切割機(jī)工廠的調(diào)研,國產(chǎn)線切割機(jī)加工精度各別廠家的各別型號(hào)線切割機(jī)可達(dá)177。一般都在177。然而,電加工燒蝕金屬表面從而改變和損壞加工面金相結(jié)構(gòu)的特性不會(huì)改變,除非用磨削或其他加工法去除這一有害層。用精密磨削法制造沖模,特別是制造高精度、高壽命沖模,諸如:薄料小間隙復(fù)合沖裁模、多工位連續(xù)式復(fù)合模等,具有尺寸精度高、工作零件加工面粗糙度Ra值小、模具壽命高等特點(diǎn)?!?,~。(4)間隙的大小與均勻度拉深、彎曲、翻邊及其他板料成形件一般都要先沖裁(落料)出平板展開毛坯,也有成形后落料、切開得到單個(gè)成品沖件。所以沖裁間隙對沖件的外廓尺寸精度有決定性的影響。對于拉深、彎曲等成形模,間隙大定將增大沖件口部尺寸誤差及回彈。(5)沖壓設(shè)備的彈性變形在沖壓過程中,沖床承載后會(huì)產(chǎn)生一定的彈性變形。6 / 6