Abstract

Certain differences between the interaction characteristics of a CO2 laser, a Nd:YAG laser and a high power diode laser (HPDL) with an alpha-alumina bioceramic have been investigated. For each laser the fluence threshold values at which significant material removal occurs were found graphically. Through the implementation of a derivative of Beer-Lambert’s law, the laser beam absorption lengths were calculated along with the thermal loading values. An examination of the laser induced meltpool propagation in the alpha-alumina revealed good agreement with the Stefan solution to the heat diffusion equation for the lasers. Absorptivity measurements revealed that there was no correlation between the actual absorptivity of the alpha-alumina and the absorption length for each of the three lasers on account of the absorptivity measurements being similar for each laser. However, differences in the depth of melting experienced by the alpha-alumina meant that it is reasonable to assume that absorption length is the principal influence on the melt depth.