差圧を利用した対向ダイスせん断法の簡便化に関する研究

抄録

The opposed dies shearing process proposed by one of the authors is based on the idea of smooth sheared surface formation utilizing a cutting mechanism and has excellent features not found in other shearing processes. This process involves two stages ; after sufficient shearing between die and protruding die, a product part is separated successively by a knock-out punch, where knock-out timing is important to prevent fracture of the surface and burr formation. Therefore, this process requires use of a precise hydraulic press which facilitates this complicated action and exact knock-out timing. This requirement seems to prevent wide practical application of this process. Therefore, we propose a simplification of the opposed dies shearing process utilizing differential pressure. First, this idea was tested using a coli spring substituted for hydraulic pressure and its feasibility was confirmed. Secondly, a differential pressure mechanism was realized with a hydraulic press and straight shearing of mild steel was achieved. Basic phenomena of this method were studied and it was found that knock-out timing is controllable by varying the pressure difference. Furthermore, a die set unit utilizing this mechanism was developed and disk blanking of aluminium with a mechanical press was demonstrated.