Effect of focus settings on laser hole drilling quality

Laser beam drilling has found widespread application in the electronic industry. The quality of the drilled hole is of prime importance in laser drilling. To achieve this goal, experimental determination of the operating parameters is essential. The present study examines the optimum focal position for the best hole drilling, since the focus setting of the focusing lens is closely related to power intensity distribution at the workpiece. The present study is limited to workpiece thickness and material, and energy as variables. The overall quality of the resulting holes is determined by assigning marks to the features of the hole geometry. This is carried out by examining the hole cross-section under a travelling optical microscope. It is found that the focus setting has a significant effect on the overall hole quality and that the drilling process may be improved by a proper combination of the process parameters.