Optimization of drilling parameters of untreated JFRP PU foam sandwich by Taguchi method

Many researchers have studied the fabrication of composite materials and their mechanical and thermomechanical properties and applications. In contrast, limited work in the field of machining of composite materials has been reported in the literature. The aim of this work is to optimize the drilling parameters such as speed, feed rate and drill diameter using a high-speed steel (HSS) twist drill and a titanium aluminum nitrate (TAN)-coated carbide twist with a drill angle of 118°. The present experimental work has been carried out using Taguchi design analysis of L₂₇ orthogonal array on jute-fiber-reinforced plastic polyurethane (JFRP PU) foam sandwich composites. A coordinate measuring machine was used to measure the drilled hole diameter to optimize the quality of the drilled hole with the combination of drilling parameters. Minitab 16 was used to investigate the variance (analysis of variance) of the test, which led to determining the significance of each parameter on drilling. The results clearly show that the HSS-twist-drilled hole exhibited a minimum thrust force of 90 N at a 3 mm dia. hole with a feed of 80 mm/min, a speed of 1500 revolutions per minute (rpm) and a torque of 0·14 N m. In contrast, the TAN-coated-carbide-drilled hole exhibited a thrust force of 88 N at a 3 mm dia. hole with a feed rate of 80 mm/min, a speed of 1500 rpm and a torque of 0·13 N m. Regression analysis evidently showed that drill diameter has the most significant effect, feed rate has a marginally significant effect and speed does not have any significant effect on minimizing the thrust force for both HSS- and TAN-drilled holes. However, the influence of torque has a marginally smaller variation for TAN compared to that for HSS. Speed and drill diameter have the most significant effect on delamination of both entrance and exit holes using the HSS tool, whereas, for delamination of both the TAN-twist-drilled entrance and exit holes, drill diameter is a more significant factor compared to speed and feed.