Machining of Half-sintered Ceramics Using a Q-switched YAG Laser.

Abstract

Lasers are regarded as an effective tool for machining ceramics; however, there exists a difficulty in improving the removal rate, because of physical properties of ceramics, such as low fracture toughness, high decomposition temperature, and melting point. To solve this problem, we attempted laser machining of half-sintered ceramics. Since half-sintered ceramics have many pores which would arrest crack propagation and low thermal conductivity, relatively slight damage and high removal rate can be expected. In this study, a laser beam of a Qswitched YAG laser was scanned on the surface of specimens to form shallow grooves. Effects of porosity of the workpieces, pulse frepuency and peak power on the removal rate were examined experimentally.The removal rate of the half-sintered specimens was found to be about 20 times as large as that of perfect-sintered ones. With an increase in the peak power of pulses, the removal rate increased greatly. The half-sintered specimens turned black near the irradiated area with no ascents of the density and hardness observed