Integrated experimental and computational approach to laser machining of structural bone.

ABSTRACT

This study describes the fundamentals of laser-bone interaction during bone machining through an integrated experimental-computational approach. Two groups of laser machining parameters identified the effects of process thermodynamics and kinetics on machining attributes at micro to macro. A continuous wave Yb-fiber NdYAG laser (wavelength 1070 nm) with fluences in the range of 3.18 J/mm2-8.48 J/mm2 in combination of laser power (300 W-700 W) and machining speed (110 mm/s-250 mm/s) were considered for machining trials. The machining attributes were evaluated through scanning electron microscopy observations and compared with finite element based multiphysics-multicomponent computational model predicted values. For both groups of laser machining parameters, experimentally evaluated and computationally predicted depths and widths increased with increased laser energy input and computationally predicted widths remained higher than experimentally measured widths whereas computationally predicted depths were slightly higher than experimentally measured depths and reversed this trend for the laser fluence >6 J/mm2. While in both groups, the machining rate increased with increased laser fluence, experimentally derived machining rate remained lower than the computationally predicted values for the laser fluences lower than ∼4.75 J/mm2 for one group and ∼5.8 J/mm2 for other group and reversed in this trend thereafter. The integrated experimental-computational approach identified the physical processes affecting machining attributes.