【文章內(nèi)容簡介】 ature of law is based on the material and thickness, presstype to determine The formula: Kfactor related with the material properties. t thickness of material. Soft materials such as 08, l0, brass, copper Z = () t In hardwood Section: A3, A 4,20,25. Z = ( 2) t Hard materials such as A5, 50 ... ... and so Z = () t Lower limit of thin materials which take. Third, the chart method In addition, you can directly determine the space lookup table values (such as teaching materials 23,24,25 table) Table 25 is the former Ministry of Machinery Industry, blanking clearance, Technical Guidance Document (JB/z27186 ) remended clearance value. Over the past China39。s general information on using Soviet gap value, from the use of the experience, the gap value is generally small. One reason for this is the classification space is not used according to the characteristics of production, the other is only as the main basis for precision stamping parts, without considering the King and the chess section with a life of quality and other important factors, so many problems exist in production. For example: Wear + blanking force. . . Therefore, in practice, in addition to special requirements of the workpiece outside the vertical section, as far as possible large gap. In addition, my experience in practice should: (1) zpunching to take the value of bigger than expected drop. (2) red holes get bigger when the z value, to prevent broken punch. (3) Carbide Die z value should be 30% larger than the steel. (4)J die orifice is coneshaped than straight smaller z value. 7 (5) highspeed stamping dies easily when the heat, f value should get bigger. (6) when the punch and die wall thin. To prevent cracking up, should be enlarged punching z. IV Size Calculation of Cutting Edge Die edge dimensions and tolerances directly affect the dimensional accuracy of Blanking, also is sufficient to guarantee a reasonable gap. Therefore, the correct calculation of the mold edge mold design dimensions and tolerances are small the work of great importance. Dimensions and tolerances in calculating the cutting edge should follow the following principles: 1. Taking into account the drop size depends on the materials and parts die size, while punching pieces depends on the size of the punch dimensions of the blanking die design should be to die as the base is difficult to stay in the punch on the gap。 Design Punching model should be based on the punch as the base, orange on the gap left in the concave. (There is a taper section, and the big end blanking parts die size = size, empty pieces of red punch small end size = size) 2. Taking into account the wear and tear will foot a larger die, the punch size decreases, in order to ensure the life of mold, the basic blanking die size should be taken close to or equal to the minimum limit of size of the workpiece。 Piercing Punch basic dimensions shall be taken as close to the or equal to the maximum limit of size of workpiece, using the smallest reasonable gap value. 3. Sampling edge of manufacturing tolerances, the workpiece should be to ensure the accuracy and timeliness based clearance requirements. At the same time easy to mold manufacturing tolerance is too large, then out of the parts may be disqualified, or one can guarantee a reasonable gap。 too small. And to die is difficult to mold manufacturing costs. Accuracy and precision blanking dies relationship table Special Note: If the size of the workpiece is not marked tolerance. I T14 without tolerances according to class to deal with, and die according to I D 11 manufacturing (nongraphic parts). Or by I T 67 class manufacturing (for round parts). Mold processing method according to the different calculation methods are 8 divided into two kinds of edge 1. Separate punch and die machining Separate processing: refers to the punch and die are processed separately by the respective drawings, mold the size of the gap processed by guarantee. Therefore, to calculate and mark out the punch and die dimensions and tolerances. This method is suitable for round or shape of a simple piece. (1) Blanking Die Blanking piece size based degree d, according to the above principles, first determine the small scale and then reduce the die size in order to ensure a reasonable punch clearance. Knifeedge part of the incidence graph of the size shown. Edge blanking die size is calculated as follows: (2) The punching die set punching size of d. (Standard tolerance) calculated according to the principles of the punch first determine the size. Further increasing the die size in order to ensure a reasonable minimum edge clearance associated with some of the dimensions in Figure 213 (b) below. Red edge aperture size is calculated as follows: Symbol meaning: Xtolerance zone offset factor, the purpose is to avoid all bias limit most blanking size (other omitted) Its value and accuracy of the workpiece. Tolerance band offset coefficient of 27 x to be investigated, or obtained by the following relations Workpiece accuracy of IT10 above: x = 1 Workpiece accuracy of IT11 ~ 13: x = Fine piece head IT14: x = In order to ensure a reasonable space, mold manufacturing tolerances must meet the following conditions Convex, concave mold separate processing advantages are: convex, concave 9 mold with interchangeable, easy to mold batch processing. Convex, concave mold separate processing disadvantage: in order to ensure a reasonable gap. Require higher levels of mold manufacturing tolerances, mold making more difficult. (Based on the use of examples to explain 6,27 table) 2. Punch and die with