A study on force affecting the head stack assembly (HSA) in ultra sonic tab bond process

Abstract

Ultrasonic Tab Bond (USTB) is one of the processes in Head Stack Assembly (HSA) production. It consists of a welding technique using high frequency vibration applied to the Actuator Pivot Flex Assembly (APFA) pad and the Head Gimbals Assembly (HGA) pad or trace being held together under pressure. The variables which are assumed to affect this process, the force of the welding tip, are analyzed in this research. The stress behavior during the USTB process was analyzed by using Finite Element Method (FEM). The results show that the stress varies directly with the force which was found to be suitable between 50 - 80 gf.