Laser drilling velocity in metals

TLDR

Efficient laser drilling in most metals occurs at absorbed intensities between 1 and 100 MW cm⁻². The study develops a theoretical model of laser drilling that accounts for liquid material expulsion. The model predicts drilling velocity and efficiency as functions of absorbed intensity, and these predictions were experimentally validated using rectangular Nd‑YAG laser pulses. Measured and calculated drilling velocities and efficiencies agree well in the efficient‑drilling intensity range where reflection losses and vapor absorption are negligible.

Abstract

To describe the laser drilling process, a theoretical model that includes expulsion of liquid material is developed. The model allows the calculation of drilling velocity and drilling efficiency as a function of the absorbed intensity. The same quantities were determined experimentally, using Nd-YAG-laser pulses of rectangular shape. Good agreement between measurement and calculation was found in the intensity region where efficient drilling is possible, i.e., where reflection losses and vapor absorption can be neglected. For most metals this region is between 1 and 100 MW/cm2.