Sequential laser and mechanical micro-drilling of Ni superalloy for aerospace application

Laser percussion drilling is inherently associated with poor geometry and thermal defects. While mechanical micro-drilling produces good quality holes, premature drill breakage often occurs and it is difficult to drill holes at acute angles. This paper presents the feasibility and basic characteristics of a new approach for micro-drilling In718 alloy sheets at an acute angle, using sequential laser and mechanical drilling. The results demonstrate that sequential laser-mechanical micro-drilling alleviates the defects associated with laser-drilled holes, reduces burr size and machining time and increases the tool life compared with mechanical drilling. (C) 2010 CIRP.