Abstract:
Ball swaging is a general method in head stack assembly process to permanently attach Head
Gimbal Assemblies (HGAs) on the carriage or actuator arm. As a result of swaging process, HGA
twisted in both longitudinal and latitudinal directions. These alter the controlled parameter for
read/write accuracy, namely Roll Static Attitude (RSA) and Pitch Static Attitude (PSA), and lead to
gram load changed. Beside the fundamental aspects (velocity, passing direction and swage ball
size.), friction coefficient is also influence. These cause complexity to the outcome and difficulties
to the analysis and improvement. In this work, the finite element method (FEM) is employed to
study and analyze the effects of mentioned parameters on the key indicator of assembly process i.e.
tightening torque and HGAs deformation. Analytical results showed that the clamping of HGA
before swaging process affects the baseplate deformation and the alignment, lead to an
unsymmetrical contact of swage ball and baseplate. Moreover, the results of effective parameters
showed that the tightening torque is inversed to the Gram Load. The larger swage ball size and
inverse shooting direction would result in increased tightening torque, whereas Gram Load is
decreased. Higher ball speed and higher friction coefficient would result in reduced tightening
torque. Nonetheless, the effective parameters studied cause insignificant effect to the slider for both
longitudinal and latitudinal directions. The benefits of this study could be used as guideline for the
development of hard disk drive industrially to enhance manufacturer competitiveness.