Numerical analysis of different tool geometries for cfrp drilling

Abstract

During the last years, the use of long fiber reinforced polymeric composite materials has experienced a considerable increase in the industry, especially in the aeronautical industry. This is mainly due to the excellent resistance-weight ratio, which places it as a suitable material capable of replacing traditional materials such as steel. One of the most common operations performed on these materials is the drilling of holes, especially in the production of large structures where the union of parts by screws is inevitable. The present work focuses on studying this operation, analyzing the influence of the drill bit both in the cutting force and in the damage generated during drilling. Two different geometries (one helicoidal and one stepped) have been tested on polymeric reinforced with carbon fiber material (CFRPs). Results showed the improvement of the quality of the holes in the case of using a stepped drill, but only working at low feed rates. With the intention of carrying out a deeper parametric study, a three-dimensional numerical model has been developed. Through experimental results, the model has been validated and used to study the influence of several factors that affect the quality of the drill, such as the supporting plate of the laminate or its thickness.