Study of Affecting Parameters in Laser Hole Drilling of Sheet Metals

Abstract

In practical applications of laser drilling the quality of the drilled hole is the critical factor, and recently methods of studying the influence on quality of the main process variables have been developed, which seek to improve quality rather than explain the drilling mechanism. Hole quality can be judged by: internal form and taper and related geometrical features, and the extent of heat affected materials. The optimum performance in laser drilling depends very much upon the proper selection of laser parameters as well as the physical properties of the workpiece material. With so many variables, and incomplete knowledge of the relationships between them, statistical methods are needed to design experiments and analyze the results. In the present work five factors at four levels were considered. Four factors are given quantative; one, the material specification, is qualitative. The result is that the design has four blocks indentified with materials each of which can be treated as a complete factorial design. However, the materials can be described quantitatively by their physical properties, so the results were correlated with the groups generated by the dimensional analysis. It is observed that main effects of laser parameters as well as their interactions, have significant effects on all features of hole geometry. Drilling medium pressure was found to be very effective factor, since its interactions with the other parameters in any order are significant.