Optimization of laser micro milling of alumina ceramic using radial basis functions and MOGA II

Muneer Khan Mohammed, Usama Umer, Abdulrahman Al-Ahmari (King Saud University, Riyadh, Saudi Arabia)

CHALLENGE - Laser milling provides an efficient method for the fabrication of micro-featured products for a wide range of materials by directly importing the design data in various CAD formats. Research on micro-milling for structural ceramics has been given less attention as compared to micro drilling and turning, most of the studies are limited to factorial analysis, and optimization in terms of multiple objectives and constraints are rare. This paper considers the analysis and optimization of an Nd: YAG laser micro-milling of alumina ceramic using smooth spline analysis of variance (ANOVA), radial basis functions (RBF), and a multi-objective genetic algorithm (MOGA-II).

SOLUTION - In this study, three input parameters, laser beam intensity, pulse repetition rate (frequency), and pulse overlap are optimized in terms of surface roughness and MRR while making microcavities in alumina ceramic using Nd:YAG pulse laser.The responses that were considered were depth per scan (DS), surface roughness (Sa), and MRR. The optimization problem is formulated as to minimize the surface roughness and maximize the material removal rate. The workflow for the optimization study is developed using modeFRONTIER software, and MOGA-II, a multi-objective genetic algorithm is used for the optimization search. 

BENEFITS - It has been found that low surface roughness for micro-milled alumina ceramic is obtained with low frequencies, low pulse overlaps, and moderate intensities. On the other hand, high material removal rates are associated with high laser beam intensities. Optimized solutions are characterized by low and moderate frequencies, high intensities, and medium pulse overlaps. Multi-objective optimization has been successfully carried out by the MOGA-II algorithms, and the optimized solutions are consistent with the ANOVA results.