The manner in which the overall energy efficiency of a small linear induction motor, previously used by the authors for impact extrusion, has been increased is described. The improved motor has been used to perform the impact blanking of 1 in and 2 in dia. circular blanks of aluminium, brass, copper, and mild steel in various thicknesses of strip. The energy required to blank when the piercing tool is initially moving at between 9 and 36 ft/s was found to be less than 50 per cent greater than that required for an identical slow-speed operation.
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