沖壓專業(yè)外文翻譯-----普通全鋼沖模的沖壓精度分析-文庫(kù)吧
2025-04-17 15:44 本頁(yè)面
【正文】 imit 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 die’s whole life, we will find that the master of the error are changeless。 the error that because the abrade of the c utter 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 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 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 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。, its roughness Ra magnitude are , height of burr are 。 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 threedimensional 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= H62 brass punching, selects C = the 40%t unilateral I
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