Co-authors​ :

 Rampal  (INDIA), Sunny ZAFAR  

Fiber-reinforced polymer composites (FRPCs) utilize high strength fibers embedded in the polymer matrix. The embedded fibers are held together by polymer matrices that act as binders and protect the fibers from chemical and environmental attacks. The FRPCs own various useful attributes, such as higher strength and stiffness for the same weight as that of bulk materials, temperature and wear resistance, non-corrosiveness, durability, and good fatigue properties. Owing to these attributes, the FRPCs find a wide range of applications. In the automobile sector, they are used to make car bodies, brake pads, drive shafts, and fuel tanks. In the aerospace sector, parts for aircraft, such as doors, noses, struts, and trunnions are made using FRPCs. They are also used to manufacture the structural parts of rockets and missiles, such as the body, nose, and pressure and fuel tanks. Manufacturing of large-sized FRPCs is arduous owing to the requirement of immense space and huge capital investment, and the difficulty in handling the large-sized FRPC parts. Therefore, after the primary manufacturing of FRPC components, fasteners are used to assemble them. To fix the fasteners, superior quality holes are desired in FRPC components for their assembly. Conventional drilling of FRPCs induces some well-known damages, such as delamination, fiber pull-out, fiber burning, and micro-cracking. These damages are the result of anisotropy and non-homogeneity of polymer composites, and the raucous tool and work interface that further generates damage inducing mechanical forces. Such damages adversely affect the residual strength of polymer composites and therefore, mitigate the durability of fastenings. Moreover, the delamination, among all damages, accounts for 60% of the total rejections of composite parts during the assembly. Therefore, the non-conventional drilling techniques play a vital role in producing good quality holes in FRPCs. The present work will explore microwave drilling and laser drilling techniques to produce holes in kenaf/polypropylene composites. Microwave drilling is a novel technique that utilizes the energy of microwaves at 2.45 GHz to produce the holes in materials irrespective of their electrical behavior. On the other hand, the laser drilling focuses the laser energy (provided in pulses) at a predefined location of the workpiece which creates a hole. The holes thus produced will be characterized for heat-affected zone (HAZ), diametral overcut, circularity, and taper angle.