Abstract
Previous statistical examination of relevant factors in laser drilling has shown that the focal settings, material thicknesses and drilling ambient pressure had a significant effect on the resultant hole geometry, but left open the question of which combination of factors gives optimum drilling. Consequently, the present work examines the optimum focal settings with material thicknesses at atmospheric and subatmospheric ambient pressures of air and oxygen for different materials. The results obtained show that the optimal setting reduces as material thickness increases at all ambient pressures.