外文翻译--冲模及复合模设计

外文原文 Stamping and Punching Dies, Compound Die Design A compound die pers only cutting operations(usually blanking and piercing) which are completed during a single press stroke. A characteristic of compound dies is the inverted position of the blanking die and blanking punch which also functions as the piercing die. The die is fastened to the upper shoe and the blanking punch having a tapered hole in it and in the lower shoefor slug disposal is mounted on the lower shoe. The guide pins, or posts, are mounted in the lower shoes. The upper shoes contains bushing which slide on the guide pins. The assembly of the lower and upper shoes with guide pins and bushing is a die set. Die sets in many sizes and designs are commercially available. On the upstroke of the press slide, the knock out rod of the press strikes the ejector plate, forcing the ejector tie rod and shedder downward, thus pushing the finished work piece out of the blanking die. Four special shoulder screws (stripper bolts), commerciallyavailable,guide the stripper in its travel and retain it against the preload of its springs. The blanking die as well as the punch pad is screwed and doweled to the upper shoe. 1、Bending Die Bending is the uni straining of material, usually flat sheet or strip metal, around a straightaxis which lies in the neutralplane and normal to the lengthwise direction of the sheet or strip. Metal flow takes place within the plastic range of the lengthwise direction of the bend retains a permanent set afterremovalof the appliedstress.The innersurfaceof a bendis in compression;the outer surface is in tension. A pure bending action does not reproducethe exactshapeof the punchand die in the metal;sucha reproduction is one of ing. The neutral axis is the plane area in bend metal where all strain is zero. 2、Bending s Metal sheet or strip, supported by a V bending, produces a bend having an includedangle which may be acute, obtuse, or of 90. Frictionbetween a spring-loadedknurled pin in the Vee of a die and the part will prevent or reduce side creep of the part during its bending. Other s are Z-bending edge bending and U-bending etc. 3、Drawing Die Drawing is a process of changing a flat, precut metal blank into a hollow vessel without excessive wrinkling, thinning, or fracturing. The various s produced may be cylindricalor box-shapedwith straight or tapered sides or sides or a combinationof straight, tapered, or curved sides. The size of the parts may vary from 0.25mm diameter or smaller, to aircraft or automotive parts large enough to require the use of mechanical handing equipment. 4、Single-action Die The simplest type of draw dies is one with only a punch and die. One type of drawing die use in a single-actionpress is shown in Fig.3-4. This die is plain single-action type where the punch pushes the metal blank into the die, using a spring-loaded pressure pad to control the metal flow. The punch has an air vent to eliminatesuction which would h