Study of the Effect of Machining Parameters on Drilling of Composite Materials and Monitoring of Process by Acoustic Emission

Drilling is one of the main machining processes carried out in the assembly stage of automobile manufacturing and aerospace components. Generally، delamination is considered as a major problem during drilling of composite materials. In this paper، the effects of feed rate، cutting speed and drill point angle on thrust force and delamination factor have been studied by using full factorial design. According to the results، feed rate has the most significant effect on thrust force followed by drill point angle. Moreover، the Half-Normal plot was used to identify which experiment factors have significant effects on the delamination factor; According to the results، feed rate has the most important effect. Acoustic emission signals and wavelet analysis were employed to monitor drilling process and discriminate frequency distributions of different cutting mechanisms. After time-frequency analyzing of AE signals، component 2 (EPC2) with frequency range of 62. 5-125 kHz was attributed to matrix cracking and component 5 (EPC5) with frequency range of 250-312. 5 kHz and average energy of 32% was attributed to fiber cutting.