Drilling performance of short Washingtonia filifera fiber–reinforced epoxy biocomposites: RSM modeling

The present study focuses on the optimization of the drilling process parameters of treated and untreated Washingtonia filifera (WF) fiber–reinforced polymer biocomposites using the desirability function approach based on the response surface methodology (RSM). Drill diameter, feed rate, and spindle speed were the three main input factors used to evaluate drilling performance. In this study, in order to have a better machinability especially a low delamination factor (Fd), the authors focused on the influence of the fiber treatment rate in the optimization of the drilling parameters. The findings revealed that diameter, feed rate, and treatment ratio were found to be important influencing factors on the delamination factor Fd. The latter was modeled statistically with a central composite design (CCD). The optimized numerical model for the delamination factor of the biocomposite reinforced with treated fiber (with 1% NaOH) showed the lowest delamination factor of 1.035 for a drill diameter of 5 mm, a feed rate of 50 mm/min and a spindle speed of 2500 rev/min. The analysis of variance (ANOVA) established the importance level of each parameter and indicated that the model was significant with a good correlation between the experimental data with R2 = 0.9713 and adjusted R2 = 0.9561.