Process control & monitoring for laser micromaching of Si3N4 ceramics

Abstract

Laser machining which is a non-contact process that offers the advantage of machining advanced ceramics. In laser machining Si3N4, surface temperature is increased and controlled to evaporate the YSiAlON glassy phase of the Si3N4. However, the formation of deep grooves often produced cracks that reduce the material strength. This work explores the diagnostic parameters of solid state lasers varying wavelength and pulse duration for ceramic micromachining. The micromachining process parameters that were monitored and controlled for laser performance are pulse energy, repetition rate and pulse duration. The focused beam size of the ultrashort laser (ns) and the longer (ns) laser pulses were 16µm and 40µm respectively. The primary aim for this research is to evaluate the two types of laser that would offer the best results with respect to material removal mechanism, micro-crack reduction, surface composition and surface roughness.