Zhang Houjiang

(School of Technology, Beijing Forestry University,Beijing 100083)

Chen Wuyi  Chen Dingchang

(School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100083)

Abstract: The formation of the exit defects in carbon fibre-reinforced plastic plates is investigated and their features in terms of drilling conditions is characterized. It is found that spalling and fuzzing are the major mechanisms of exit defects and spalling is usually a severer damage. The spalling, consisting of a main region and a secondary region, is caused by chisel and cutting edge actions, in which the former plays a key role. The fuzzing, however, exists in the cutting region where the included angle between the fibre direction of the surface ply and that of the cutting speed is acute. A severer spalling damage corresponds to a low spindle speed, a high feed speed, a large feed rate and a great thrust force. There exists a critical ratio of cutting speed to feed speed, which is about 3 000~4 000, beyond which the spalling size can be minimized.

Key words: Carbon fibre-reinforced plastics  Spalling  Fuzzing  Drilling conditions

CLC No: TQ327

人事部2002年度留学回国人员科技活动择优资助项目. Received 20030630, received in revised form 20040130