The Development of Burr-Free Blanking: Roll Blanking

Summary

Optimum conditions were studied to achieve clean, burr-free blanking using a newly developed method called roll blanking. This method consists of two steps; that is, in the first step the sheet metal is half-sheared, but not subjected to perfect separation of blank and scrap, and in the second step the material is passed through a roll gap adjusted to the material thickness, the blank being separated from the scrap hole. In this new blanking method, a negative clearance close to zero was found to be best for facilitating this method and obtaining the squareness of sheared edge. By introducing the idea of a virtual punch and a virtual die in the second step, the characteristic of the roll blanking process can be well explained. The experiment was performed mainly on circular blanking of aluminium, mild steel, and stainless steel sheets. By application of roll blanking, a toothed wheel was successfuly made.