Improvement of drill geometry for drilling CFRP composite

Syahibul Hafiz, Basir (2014) Improvement of drill geometry for drilling CFRP composite. Project Report. UTeM. (Submitted)

Text Improvement of drill geometry for drilling CFRP composite.pdf Download (1MB)

Abstract

Generally, CFRP are joined and connected by joining elements into one composite section. For this purpose, it is necessary to drill numerous holes which poses several challenges due to its inhomogeneous materials that consist of fibre and matrix. Drilling of CFRP can damage the hole in the form of delamination, fibre pull out, rough surface, edge chipping, uncut fibre and rapid tool wear which associate with the drill geometrical features. From literature, it shows that dagger drill with suitable design is the most suitable drill type for drilling CFRP. Thus, this project attempts to investigate and propose the optimal design of dagger drill for effectively drilling CFRP composite. Two dagger drill geometric design will be investigate namely point angle and tool facet on hole surface roughness, delamination and drilling force using statistical RSM. Total of nine drill design are fabricate with varying point angle and tool facet. From the conducted investigation, it shows that drilling carbon fiber reinforce polymer CFRP was substantially affected the surface towards fibre formation, burr and lead to condition of surface roughness. The explanations about evolution of cutting force and analysis of damage progression have assisted in understanding the drilling phenomenon by increase the point angle and facet. The value of delamination number produces by different type of drill bit tool in the design expert demonstrated the circumstances prevailing at the workpieces drilling surface. In addition, the optimal geometric design for drilling CFRP are by using 110º point angle with five tool facet. A set of experimental test were done to validate the selected optimal tool design. The strong agreement of 90% were found between predicted and actual value confirmed the effectiveness of the design for effective drilling of CFRP composite.

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