The Effect of Carbon Fiber Reinforced Polymer (CFRP) Micro Drilling Parameter on Hole Accuracy

The research was executed to study the effect of Carbon Fiber Reinforced Polymer (CFRP) micro drilling parameter on hole accuracy. The main contribution of this research is to improve manufacturing process of hole micro size by finding the optimum parameter for excellent hole accuracy. However, to obtain the optimum parameter, the behavior of hole quality must be investigated. The parameters considered in the experiment were machine spindle speed and cutting feed rate. The experiment was carried out by drilling CFRP panel using the router machine with micro drill bit (D0.9 mm) to make holes while a measuring microscope was used to observe and analyze the holes. The quality of hole created on each panel was compared, and at the same time, the hole diameter was measured to determine hole accuracy. In term of hole diameter, as the number of drilled holes increased, the diameter of holes reduced for both entry and exit hole. Minimum diameter of entry hole at spindle speed 8,000 rpm and 10,000 rpm were 0.8986 mm and 0.8973 respectively while maximum diameter of entry holes were 0.9297 mm and 0.9234 mm each. Similar pattern occurred at the exit holes as well. The result shows a linear relationship between hole accuracy, hole quality and number of drilled holes, it was also found that the spindle speed did not have a significant impact and there is a need to test the feed rate. In this regard, determining the excellent hole accuracy of CFRP is useful for mechanical assembly process of aircraft parts.