Computer-Aided Design and Manufacture of High Speed Cropping Tools

Summary

A duplex form of tool which consists of a hard insert shrunk inside a bulky carrier is normally used for the high speed cropping of circular bars. The insert, with a hole to match the bar dimensions, provides good support during cropping and helps to improve the billet quality. The compressive stress induced as a result of the interference fit, on the other hand, keeps the relatively brittle insert in one piece when the tool carrier experiences heavy impact blows. A considerable effort and time are needed in the design of such cropping tools as the space available is usually restricted calling for an optimum design. As the present paper shows, once the design rules have been formulated, a micro-computer can be used to speed up the operation. With an inter-active approach, the developed programme produces not only the final dimensions but also simple drawings and should it be desired, an N.C. tape for machining the die insert.