Empirical Modeling and Optimization of Laser Bending Process Parameters using the Central Composite Design Method for HDD Slider PSA/RSA Adjustment

Abstract

This paper details the development and optimization of a laser adjustment process for the pitch static attitude and roll static attitude (PSA/RSA) to achieve the maximum bending angle without the burning of materials. The effects of process parameters (or factors) including the laser power, pulse repetition rate, and scanning time were investigated based on the central composite design method. Experiments were performed on a stainless steel (SST-300 series) suspension using a solid-state laser system and a charge-coupled device camera with image processing technology. Regression models of positive and negative PSA/RSA (or response) values were developed through a total of 20 experimental runs. The results showed that the PSA/RSA bending angle increases with increasing laser power and pulse repetition rate, while the bending angle decreases with increasing scanning time. The optimization determined that a higher laser power and lower scanning time had a more significant effect on the bending angle. However, the laser power cannot be increased above the melting point of the material, as this will lead to the formation of spongy debris on the stainless steel. The models were shown to accurately describe the relationship between the factors and responses. In addition, the laser bending mechanism for the PSA/RSA adjustment of a hard disk drive slider was investigated.