Investigation on roundness and taper of holes in drilling GFRP composites with variable weight percentages of glass fiber

Abstract

Mechanical fastening technique plays a vital role in aerospace and automotive industries because of their ability to make large assemblies in composite materials. However, it is challenging to drill holes in composite materials which are free of defects. Thus, the paper investigates the influence of glass fiber content within the GFRP composites during the drilling operation. Different hole quality parameters such as roundness deviation, delamination, fiber pull-out, taper angle were observed as they contribute to better machinability and improved surface quality while drilling. A radial drilling machine was used to perform the drilling process on the composites keeping a constant rotational speed and feed rate. Only fiber weight percentages were varied. The experimental results exhibited that the drilled surface quality is closely related to the percentage of the fiber content of the specimens. In terms of roundness deviation, delamination, fiber pull-out, and taper angle, a better result is achieved for the composite specimen having comparatively lower glass fiber content.