Analysis of subsurface damage during milling of CFRP due to spatial fibre cutting angle, tool geometry and cutting parameters

Abstract

During machining of carbon fibre reinforced plastics the anisotropy of the material and the resulting cutting conditions can cause various types of damage such as delamination, burrs or subsurface damage. Subsurface damage can lead to a reduction in surface quality or component rejection. In this paper, a new method is used to detect subsurface damage caused by peripheral milling over the entire cut. This analysis, using a newly defined spatial fibre cutting angle θne, tool geometry and process parameter, provides a deeper understanding of the damage formation. While the damage area varies with the uncut chip thickness and the rake angle of the tool, the cutting edge rounding and the fibre cutting angle prove to be important in determining the depth of damage. The detected damage area is 44-65% of the fibre cutting angle range from 0° to 90°, which can be extended up to 12 % due to the damage depth when milling an external radius.