Abstract: Various types of defects may be introduced during manufacturing and drilling of carbon fiber reinforced plastics, and they will influence on the final quality and performance of the structures. A method, in which the inner-defect is simulated by changing the cure temperature of the prepreg, is proposed to investigate the influence of the manufacturing-induced defects on the quality of drilling exit. Specimens with different cure temperatures and lay-up styles are used to simulate the drilling process, and the influence of residual stiffness on the growth of inner-defect and the exit quality is discussed. The results show that the cure temperature has a great influence on the exit quality, which indicates that manufacturing-induced defects have significant effect on the drilling quality; when the cure temperature is higher than 140 ℃, acceptable quality can be obtained; when the uncut material is in the form of 0°/90°/0°/90° lay-up, the inner-defect will not propagate for high residual stiffness even when the cure temperature is as low as 100 ℃.

Key words: Carbon fiber, Composite materials, Cure temperature, Defect, Drilling, Resin