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#100 Fundamentals of Press Die Structure Design (9) Considerations Regarding Die Machining and Maintenance

Category : Die Design
November 4, 2011

Fig. 1 shows the structure of the part of the die that carries out upward bending inside a progressive die. The parts (a) and (b) of this figure show the conditions before and after forming the metal. The upward bending die projects above the die plate surface (the dimension "s"). Instead of preparing in an integral manner, by inserting a spacer with a thickness of (s) as shown in the figure, it is possible to make the thicknesses of the upward bending die and the knock out equal to the thickness (T) of the die plate, and it is possible to make it easy to form the part. By doing this in the case of an integrated type die plate, it is possible to maintain the dimension (s) constant by removing the upward bending die during maintenance, taking out the spacer, inverting and replacing the upward bending die, and re-grinding, thereby making maintenance easy.

Fig. 1 Upward bending die structure considering maintenance and part machining

Fig. 2 shows a technique related to the life of inserted parts. In Fig. 2 (c), a new part has been inserted. The fixing screw of this part has been modified so that the bolt is inserted deeper by the amount of re-grinding. Although the level is adjusted by inserting a shim on the underside of the inserted part every time the inserted part is re-ground, it is possible to know that the inserted part has reached its life when the head of the bolt is almost at the same level as the die surface. The machining can be made so that it is possible to know the time to replace the part.

Fig. 2 Re-grinding inserted parts and measures for maintenance

Fig. 3 shows the life management using the punch. As is shown in Fig. 3 (e), a spacer corresponding to the amount of regrinding is inserted. The spacer is ground to match with the amount of re-grinding of the punch, and a shim equivalent to the amount of grinding it provided at the head part. Fig. 3 (f) shows that state. The life of the punch can be said to have ended when the spacer disappears. In the case of the structure of Fig. 3 (e), it is necessary to separate the top die at the time of taking out the punch. If the structure is made like that shown in Fig. 3 (g) it is possible to eliminate the tediousness of separating and the preparation of the shim.

Fig. 3 Measures for maintenance of a round punch

Various techniques are possible if modifications are made paying attention to detailed parts. Use various techniques in part design in order to make it easy to use.

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