Tapered alignment guide arrangement for self aligning part excision die

Abstract

The lower ends of alignment bearing shafts of an upper die member of a tape automated bonding apparatus are modified to include tapered alignment pins, each having a tapered surface that is complementary to the tapered interior end of the bore of a respective bushing on a lower die member. The alignment pin serves to guide its associated alignment shaft and a ball bearing sleeve carried thereby into the bushing. In addition, a first set of rails is installed directly beneath a die member actuator, and a second set of rails is installed on the upper die member. The second set of rails slide upon the first set of rails, so that the upper die member effectively mechanically floats on the first set of rails. The lower die member is affixed to a translatable platen, which is driven to an end stop position at the part excision station. Then, the upper die member is lowered onto the lower die member, so that the alignment pins contact the bores in the bushings on the lower die member. Any axial misalignment of the alignment shafts and the bushings is removed as the tapered surfaces of the alignment pins discs are translated by a horizontal force imparted by the bushings. As a result, the upper die member is horizontally aligned with the lower die member, so that the ball bearing cages automatically enter into the bores of the bushings on the lower die member.