Fundamental processes in laser drilling and welding

Abstract

Laser penetration processing of a variety of transparent and translucent dielectrics was carried out under varying gravitational levels. Real time differential holographic interometry was used to measure heat transfer in laser drilling of fused quartz in zero and normal gravity. Measurements were compared with a numerical model based on a prolate spherical coordinate frame. The model agrees well with experiments close to the surface, but overestimates the extent of the heat transport deeper into the quartz.

Modulated beam intensity drilling of liquids is studied. Frequency dependent structures are observed, particularly in glycerol drilling which exhibit transitions to extremely stable resonant states. A potential mechanism for this resonance is presented.

Laser drill hole initiation in glycerol and acrylic is studied. A parametric energy conservation model is developed and found to be well suited as a laser beam intensity diagnostic.

CW Laser drilling of glycerol-water mixtures and gelatin is studied and dynamical behaviour is discussed in terms of material property differences in viscosity and environmental factors associated with gravity.