Effect of Machining Parameters and Stacking Sequence on Delamination, Thrust Force, and Torque in Drilling Natural Fiber–Reinforced Hybrid Jute–Ramie Composites
Abstract
Due to sustainability, biocomposites are gaining applications in construction, textile, packing, and automotive industries. Mechanical characteristics of biocomposites can be enhanced by hybridizing two or more fibers. However, manufacturing feasibility plays key role in maintaining product quality. Drilling is the most widely used machining process for making holes to facilitate product assembly, where the quality of the drilled hole depends on various machining parameters such as spindle speed, feed rate, and drill-bit type. In this study, effect of machining parameters on jute-ramie fiber-reinforced hybrid composites with different stacking sequences was examined. A four factor (drill-bit type, spindle speed, feed rate, and stacking sequence) and five level L25 Taguchi array with five different drill-bits (HSS, HSS-E, TiAlN carbide, Brad & Spur, Cu carbide) of 4 mm diameter, feed rate (10–50 mm/min in intervals of 10 mm/min), and spindle speed (300–1,500 rpm in intervals of 300 rpm) were used for design of machining experiments. Optimum drilling parameters and percentage contribution to thrust force, torque, and delamination factor were determined from the grey relational analysis and analysis of variance. Drill bit had major influence on drilling performance with contribution of 83.26 % to thrust force and 79.80 % to torque followed by spindle speed. Drilling with HSS-E and TiAlN carbide drill-bits resulted in greater delamination factor at the entry and exit comparing with other bits. HSS and Cu carbide bits were found to be suitable for machining jute and ramie-based composites. Stacking sequence had significant influence on torque, whereas feed rate did not show any significance on outputs. Overall, drilling JJJJJJ specimen at 1,500 rpm and a 50-mm/min feed rate resulted in an optimum quality hole, whereas a poor-quality hole was obtained drilling RRJJRR specimen at 600 rpm and a 50-mm/min feed rate.