A Study on Laser Assisted Machining for Silicon Nitride Ceramics (Ⅰ) - Preheating Characteristics and Oxidation Behaviors of Silicon Nitride Ceramics with Machining Parameters

Kim, Jong-Do; Lee, Su-Jin; Suh, Jeong; Lee, Jae-Hoon

JWJ > Volume 28(4); 2010 > Article

Journal of KWJS 2010 August;28(4) :61-66.
Published online September 8, 2010.

A Study on Laser Assisted Machining for Silicon Nitride Ceramics (Ⅰ) - Preheating Characteristics and Oxidation Behaviors of Silicon Nitride Ceramics with Machining Parameters

Jong-Do Kim, Su-Jin Lee, Jeong Suh, Jae-Hoon Lee

Correspondence: Published online September 8, 2010

ABSTRACT

Silicon nitride is widely used as an engineering ceramics because it has high strength, abrasion resistance and corrosion resistance even at high temperature. However, machining of silicon nitride is difficult due to its high hardness and brittleness. Laser assisted machining(LAM) allows effective cutting using CBN tool by locally heating the cutting part to the softening temperature of YSiAlON using the laser beam. The effect of preheating depending on process parameters were studied to find out the oxidation mechanism. If silicon nitride is sufficiently preheated, the surface is oxidized and N₂ gas is formed and escapes from the material, thereby making the cutting process more advantageous. During laser preheating process before machining, high temperature results in strong oxidation which makes the bloating, silicate layers and micro cracks. Using the results of these experiments, preheating characteristics and oxidation behavior were found out.

Keywords: Silicon nitride;HPDL;LAM;Oxidation behavior;Machining parameters