碳纤维复合材料(CFRP)钻孔出口缺陷的研究

对碳纤维复合材料(CFRP)钻孔出口的缺陷进行了试验研究,对其典型形式进行了模型总结,指出孔出口缺陷由撕裂和毛边两部分组成,其中撕裂比毛边的尺寸大。撕裂的形成过程包括两个作用阶段即横刃作用阶段和主切削刃作用阶段,其中横刃作用在撕裂形成中占主导成份。毛边缺陷通常出现在表层纤维被“顺向”切削的孔边缘部分。另外,以孔出口两侧撕裂长度平均值作为撕裂评价参数,在总结钻削试验结果的基础上探讨了钻削参数变化对撕裂大小的影响。指出随着进给速度、进给量、钻头直径和轴向力等因素的增大,撕裂缺陷将变得严重;钻头转速的增大将使撕裂值变小;将切削速度与进给速度比值控制在3000-4000以下,可以有效地减小撕裂值。

INVESTIGATION OF THE EXIT DEFECTS IN DRILLING CARBON FIBRE-REINFORCED PLASTIC PLATES

The formation of the exit defects in carbon fi-bre-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, consist-ing 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 3000-4000, be-yond which the spalling size can be minimized.