Effect of Drilling Force on Delamination of Abaca/Kenaf/Carbon Fiber Reinforced Hybrid Composite

Background: Natural fiber reinforced materials with polymer matrix finds many applications in industries due to its excellent property. Fiber laminate composite materials have been researched around the globe and were tested to determine its beneficial properties for specific purposes. These composite materials have improved to withstand external loads. However, drilling of composite has remained a difficult task because of its anisotropic material properties. Methods: In this study abaca and kenaf woven mat with the carbon woven mat are laminated using epoxy resin (HY 951) and hardener (LY556) as matrix element while preparing the hybrid composite materials. The drilling operations are carried out using automatic feed computer controlled vertical axis drilling machine. Results: It is found that the drilling force, delamination peel up and push out for the composite material depended on feed rates, drill bit diameters and speeds respectively. The optimal input parameters are obtained using Taguchi L27 orthogonal array, Response Surface Methodology (RSM) and Analysis Of Variance (ANOVA) methods. It is observed that lower feed, smaller drill diameter and moderate speed provided high quality drilled hole. The drilled-hole quality, drilling damages are observed by using profile projector. Conclusion: The following conclusion can be drawn from the present investigation on drilling of reinforced composite materials drilled in different conditions. Feed rate is the important factor compared to the feed and the tool diameter. When feed rate is increased, thrust force also increases. However, thrust force decreases when the cutting speed increases. Feed influenced the thrust force instead of speed and torque during drilling. The drilling induced damages are minimum during lower feed and lower diameter drill. Hence, lower drill diameter, lower feed rate and medium speed are more suitable for drilling the hybrid composites.