LAUSR

Abstract In this paper, an assessment of micro holes quality in carbon fiber reinforced polymer (CFRP) composite was based on thrust force and damage formation. Carbon fiber T300 reinforced polyphenylene sulfide (PPS) was micro drilled with 0.6 mm diameter twist drill under three different strategies: direct, supported and pilot drilling. It was observed that when thrust force was measured under uncut chip thickness smaller than 77.5% of the drill lips edge radius (re,lips) a size effect was detected. However, when this cutting condition is achieved, a drift was identified in the cutting force value showing a conversely behavior from that observed during micro cutting of metals. This effect was attributed to a rheological phenomenon taking place at reduced cutting condition. It was observed that smaller drill feeds per rotation play an important role upon the size effect and damages formation. Based upon the results, delamination damages were not found due to the low thrust force levels and small drill feeds per rotation acquired. It is proposed that different cutting strategies may be applied to mitigate the formation of defects at the entry and exit of the holes in micro drilling of composites.