【正文】 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。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。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。無搭邊排樣沖件。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，沖件平直無拱彎，176。這類沖件通常是在沖模失效報廢前沖制的最后一批合格沖件。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合格沖件為止，沖件實際具有的誤差。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。 or bigger somewhat, was individual also can achieve177。 Flushesthe structure rigidity and the threedimensional shape affects itsshape position precision.(2) punching craft and molder structure typeUses 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= H62 brass punching, selects C = the 40%t unilateral I kind ofsmall gap punching pared to select C = 8%t (unilaterally) III kindof big gap punching, will flush a fixed error to enlarge 40% ~ 60%, theprecision at least will fall a level. Side in addition, whether thereis picks builds a row of type side, flushes a error to have far to bebigger than has builds a row of type to flush. Side not builds a rowof type to flush. Side not builds a row of type to flush a precisionto be lower than the IT12 level side, but most has builds a row oftype to flush a precision in IT11 between ~ IT9 level, material thickt 4mm flushes, the size precision can lower some. Different die’s 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, multilocations continuous type pound die because flushes continuously toduplicate the localization to add on the pattern making error to bebigger, therefore it flushes a fixed error pound punching die to wantpared to the single location Big 1 ~ 2 levels
(3) the craft of punching die’s manufacturethe 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 plex cavity. But its processing surfaceapproximately is thick ~ 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 CorradaCorporation39。外文文獻(xiàn)資料General allsteel punching die’s punching accuracyGeneral allsteel punching die’s punching accuracyAccuracy 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 pound mould of pound punching’s accuracy, is typicalne