Drilling high aspect ratio holes in polyethylene with frequency doubled Nd:YAG laser radiation

Abstract

We describe results obtained on the drilling of 10-15 μm diameter holes in polyethylene with an aspect ratio exceeding 10:1 using focused Q-switched 532 doubled Nd:YAG pulses. Holes may be drilled with as few as 25 pulses with a pulse energy of about 0.2 mJ, making this process feasible with diode pumped Nd:YAG systems. We discuss the relationship between variables such as pulse energy, f-number of the focusing system, focal position, and plastic thickness and show how these are related to the number of pulses required for clearing a hole in a sheet of given thickness and entrance and exit hole diameter. A simple model will be inferred from these relationships and used to describe some physical processes associated with drilling of small diameter high aspect holes in semi-transparent polymers.We describe results obtained on the drilling of 10-15 μm diameter holes in polyethylene with an aspect ratio exceeding 10:1 using focused Q-switched 532 doubled Nd:YAG pulses. Holes may be drilled with as few as 25 pulses with a pulse energy of about 0.2 mJ, making this process feasible with diode pumped Nd:YAG systems. We discuss the relationship between variables such as pulse energy, f-number of the focusing system, focal position, and plastic thickness and show how these are related to the number of pulses required for clearing a hole in a sheet of given thickness and entrance and exit hole diameter. A simple model will be inferred from these relationships and used to describe some physical processes associated with drilling of small diameter high aspect holes in semi-transparent polymers.