ON HIGH-SPEED PRECISION BLANKING OF IC LEAD-FRAMES USING A PROGRESSIVE DIE

The factors affecting the dimensional accuracy of blanked IC lead-frames are discussed. Attention is focussed on the elimination of the residual stress in the material caused by roll-slitting. Improvement in the designing and manufacturing of the blanking tool is explained and the mechanism of vibration of the stripper in high-speed blanking is analyzed. A high speed precision press that has been developed in Japan is introduced. The effects of blanking conditions such as tool clearance, strip-holding force, lead-shape, and order of blanking are explained, using a newly proposed mechanical model. © 1990.