Optimum airflow to reduce particle contamination inside welding automation machine of hard disk drive production line

Abstract

Welding automation machine (WAM), used for welding minute components to the head gimbal assembly (HGA) of a hard disk drive (HDD), needs to operate in a strictly clean environment. In today’s HDD factories, to prevent airborne particle contamination to the WAM, Fan Filter Units (FFUs) are installed on top of it to supply clean air and blow away outside airborne micro particles, keeping the microenvironment clean. Furthermore, the mass of the clean air should also carry away harmful particles generated inside the microenvironment. In this research, numerical simulation of airflow inside a WAM was performed in order to verify these cleaning functions of the airflow. A transition shear stress transport turbulence model was employed to simulate airflow from the FFUs through and out of the microenvironment. The simulation results showed that the airflow from the FFUs truly performs the two cleaning functions as intended. Moreover, they also revealed that the optimum air speed, the speed resulting in the lowest particle counts, is in the range of 0.35–0.55 m/s. Our findings can be useful for developers who may use FFUs to reduce particle counts in the environment of other types of industrial machinery.