【模具与数控专业英语】教学内容2106市公开课获奖课件省名师优质课赛课一等奖课件.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,本资料仅供参考，不能作为科学依据。谢谢。本资料仅供参考，不能作为科学依据。本资料仅供参考，不能作为科学依据。谢谢。本资料仅供参考，不能作为科学依据。,Unit Two Die Design,模具与数控专业英语,1/18,2.6 Drawing Die,模具与数控专业英语,2.6.1 Drawing Die Processes,Drawing is a process of changing a flat，precut metal blank into a hollow vessel without excessive wrinkling，thinning，or fracturing,The various forms produced may be cylindrical or box-shaped with straight or tapered sides or a combination of straight，tapered，or curved sides,Many parts made of sheet metal are cylindrical or box-shaped:for example,pots and pans,containers for food and beverages(Figure 2-17),kitchen sinks,and automotive fuel tanks.,2/18,模具与数控专业英语,Such parts are usually made by a process in which a punch forces a flat sheet-metal blank into a die cavity (Figure 2-18).,Although the process is generally called deep drawing,on account of its capability of producing deep parts,it is also used to make parts that are shallow or have moderate depth.,3/18,模具与数控专业英语,Figure 2-17 The metal-forming process,4/18,模具与数控专业英语,Figure 2-18 Drawing process on a sheet-metal blank,5/18,模具与数控专业英语,Metal flow-When a metal blank is drawn into a die，a change in its shape is brought about by forcing the metal to flow on a plane parallel to the die face，with the result that its thickness and surface area remain about the same as the blankFigure 2-19 shows schematically the flow of metal in circular shells.,The units within one pair of radial boundaries have been numbered and each unit moved progressively toward the center in three steps.,6/18,模具与数控专业英语,If the shell were drawn in this manner,and a certain unit area examined after each depth shown,it would show(a)a size change only as the metal moves toward the die radius;(b)a shape change only as the metal moves over the die radius.Observe that no change takes place in area b,b1=b2=b3=b;and the maximum change is noted in area a,a1 a2a3.a.The outer-ring area of flat sheet is main change and no change in the bottom touched with punch.,7/18,模具与数控专业英语,Figure 2-19 A step-by-step flow of metal,8/18,模具与数控专业英语,2.6.2 Drawing Die Design,Single-action Dies-The simplest type of die is one with only a punch and dieEach component may be designed in one piece without a shoe by incorporating features for attaching them to the ram and bolster plate of the press,Figure 2-20a shows a simple type of draw die in which the precut blank is placed in the recess on top of the die，and the punch descends，pushing the cup through the dieAs the punch ascends，the cup is stripped from the punch by the counterbore in the bottom of the die,9/18,模具与数控专业英语,The top edge of the shell expands slightly to make this possible,The punch has an air vent to eliminate suction which would hold the cup on the punch and damage the cup when it is stripped from the punch,The method by which the blank is held in position is important，because successful drawing is somewhat dependent upon the proper control of blankholder pressure,10/18,模具与数控专业英语,A simple form of drawing die with a rigid flat blankholder for use with 13-gage and heavier stock is shown in Figure 2-20b,When the punch comes in contact with the stock，it will be drawn into the die without allowing winkles to form,11/18,模具与数控专业英语,（a）(b),Figure 2-20 Draw die types,12/18,模具与数控专业英语,Another type of drawing die for use in a single-action press is shown in Figure 2-21.,This die is a plain single-action type where the punch pushes the metal blank into the die，using a simple-loaded pressure pad to control the metal displacement,The cup either drops through the die or is stripped off the punch by the pressure pad,The sketch shows the pressure pad extending over the nest,which acts as a spacer and is ground to such thickness that an even and proper pressure is exerted on the blank at all times,13/18,模具与数控专业英语,If the spring pressure pad is used without the spacer，the more the spring are depressed the greater the pressure exerted on the blank，thereby limiting the depth of draw,Because of limited pressures obtainable，this type of die should be used with light-gage stock and shallow depths,A single-action die drawing flanged parts，having a spring-loaded pressure pad and stripper，is shown in Figure 2-22,14/18,模具与数控专业英语,The stripper may also be used to form slight indentations or re-entrant curves in the bottom of a cup,with or without a flange,Draw tools in which the pressure pad is attached to the punch are suitable only for shallow draws，The pressure cannot be easily adjusted，and the short springs tend to build up pressure too quickly for deep draws,This type of die is often constructed in an inverted position with the punch fastened to the lower portion of the die,15/18,模具与数控专业英语,Figure 2-21 with spring pressure pad Figure 2-22 with spring,pressure pad and stripper,16/18,模具与数控专业英语,Deep draws may be made on single-action dies，where the pressure on the blankholder is more evenly controlled by a die cushion or pad attached to the bed of the press,The typical construction of such a die is shown in Figure 2-23This is an inverted die with the punch on the dies lower portion,17/18,模具与数控专业英语,Here,we should also make clear the concept in drawing die design:,(a)Drawingthe general term for sheet-metal forming and more specifically the behavior of material in the flange of a product that gets drawn into the die wall.,(b)Deep-drawingessentially the same as drawing but often related to processes that use several repeated drawing operations so that long products can be formed.,18/18,