To date, most of composite drilling optimization studies have been focused on conventional thermoset CF/epoxy . Since the optimization usually involves multiple objectives (e.g. a range of hole quality metrics and production efficiency, etc), some early researchers dealt with such multi-objective optimization problem using the weighted sum method . Specifically, a set of weighting factors were deployed to convert a multiobjective problem into a traditional single-objective solution. For instance, Feito et al. designed a full factorial experiment for multi-objective optimization of CF/epoxy drilling. Analysis of variance (ANOVA) was utilized to reveal the effect of feed rate, cutting speed and tool geometry on drilling thrust force, torque and hole delamination. The relationship between input and output variables was established by means of response surface methodology (RSM). The multi-objective problem was converted to a single-objective problem through assigning weighting factors according to the relative importance of each objective. Results showed that low feed rate (0.05 mm/rev) was preferable under all conditions. However, the optimal cutting speed can be greatly affected by the value of weighting factors assigned to each objective. In another study by Feito et al. , optimization of CF/epoxy woven composite drilling was conducted under different tool wear conditions.