【正文】 （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、切開得到單個成品沖件。（3）沖模制造工藝沖模主要工作零件即凸、凹模的加工程序，對操作上的技術要求不高，能夠一次成形較復雜的模腔。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，而此時的沖模具有初始沖壓精度。沖模的制造精度及質(zhì)量又取決于制模工藝。gang 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 plete high accuracy NC and theCNC line cutter, the processing precision may reach 177。 and also have another part error are unconventional , unforeseen. Therefore, every die’ s error are posed of fixed error, system error, accident error and so on. 1. fixed error 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. It’s 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 panelthe 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 pletely different gap and punching accuracy. A gear H62 which made in yellow brass with the same mode number m=, 2mm thick and had a center hole, when the gap get C=%t (single edge) , and punched with pound punching die, and the dimension accuracy reached IT7, the part have a flat surface ,the verticality of tangent plane reached 176。沖模的沖壓精度分析對沖模投產(chǎn)至失效報廢各個時期沖件的實際誤差分析，可以看出其增大的時期及趨向，從而分析其增大的因素。同理，沖件外形落料按單向負偏差標注允差并依接近或幾乎等于極限最小尺寸制模。除上述片齒輪實例說明，精沖工藝與普通沖裁的沖件精度與固定誤差相差一個數(shù)量級之外，即便在普通沖裁中，采用不同間隙沖裁，固定誤差相差也很大。個別也能達到177。雖然這種變形量依沖壓力的大小變化且具有明顯的方向性，但就沖壓件，主要是對具有體積沖壓性質(zhì)的壓印、壓花、校平、壓凸、起波、沖擠、鐓形、翻邊、鐓粗、打扁、變薄拉深等工藝作業(yè)沖制成形的沖件，對其沖壓方面的尺寸精度有重大影響。～177。一旦選定間隙就確定了沖件的平面尺寸的固定誤差的主體；沖件結(jié)構剛度及立體形狀則影響其形位精度。///////沖件上孔與內(nèi)形因凸模磨損尺寸會逐漸變?。黄渫庑温淞铣叽鐣虬寄Ｄp而逐漸增大。但其準確性的沖壓零件的尺寸和位置精度線性幾乎取決于沖裁下料精度。 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 pound dies. Therefore, the analyse of burr and measurement is especially important when do them as enterprise standardization or checked with the height of punching part.The initial error usually is the minimal through the whole life of die