MACHINING PERFORMANCE WITH RESPECT TO CUTTING FORCES, VIBRATIONS AND SURFACE QUALITY IN DRILLING OF HYBRID ABACA AND GLASS FIBERS REINFORCED POLYMER COMPOSITE

Abstract

Initially,polymer composites utilized synthetic fibers as reinforcements due to their high strength and excellent water resistance. However, synthetic fibers are non-biodegradable, and their manufacturing process involves chemicals, rendering them environmentally unfriendly. Consequently, natural fibers began to be employed owing to their low production costs and inherent biodegradability. Nevertheless, natural fibers possess lower strength and non-uniform sizes, making them challenging to shape. Hybrid composites have been developed to address these limitations, combining synthetic and natural fibers to leverage their respective advantages and mitigate each other’s shortcomings. As a result, hybrid composites are increasingly being adopted in various industries, including automotive, construction, sports, and electronics. During production, hybrid composite panels still require machining processes, such as milling to smooth the surface and drilling to create connecting holes, to become final products. Careful selection of machining parameters are needed to ensure product quality and minimize defects, including tool wear, fiber debonding, and delamination. Cutting forces and vibrations, critical factors influencing machining performance, can be regulated through optimized cutting conditions. This study examines the effects of cutting conditions on cutting forces and vibrations while drilling hybrid composites composed of abaca and glass fibers. Composite panels were fabricated using the compression molding method, consisting of 10% abaca fiber, 10% glass fiber, and 80% polyester resin with 1% hardener by weight. Drilling experiments were conducted using a two-flute highspeed steel (HSS) cutting tool under varying spindle speeds and feed rates. The results revealed that cutting parameters significantly influenced machining behaviour. Specifically, higher spindle speeds increased cutting forces by up to approximately 15%, whereas higher feed rates amplified vibration acceleration by up to 67.8%. These findings contribute to a deeper understanding of machining performance and provide valuable insights for optimizing drilling parameters to enhance machining efficiency and surface quality in hybrid natural– synthetic fiber composites.