Effect of annealing on quality enhancement of micro-machining green alumina ceramics by laser ablation

Abstract

The natural characteristics of sintered ceramics limit the micromachining of functional surface textures in terms of tool wear, processing quality and economic effectiveness. So, the micro-machining of green ceramics before completely sintering is introduced. In this paper, micro-channels are fabricated on the surfaces of green ceramics pretreated by different annealing temperatures. The effect of parametric combination of annealing temperature and laser parameters on the response of processing quality, channel dimension and material removal rate (MRR) are studied by single fact experiments and multi-objective optimization by the response surface method (RSM). The mathematical models of the interaction between different factor combinations are developed based on RSM. Results show that the annealing temperature has significant influence on the aspect ratio under different laser parameters. Continuous channels with few recast layers are always formed at the annealing temperatures of 500–800 °C and a higher annealing temperature always contributes to a larger aspect ratio. Based on the responses of RSM, the optimal parameters of laser ablation and annealing temperature are chosen as laser power of 6 W, scanning speed of 350 mm/s, laser frequency of 40 KHz, and the pretreatment annealing temperature of 750 °C. The experiments validate good agreement of proposed model.