Study of the surface integrity during CFRP trimming: Tool material and geometry, fiber orientation and tool wear effect analysis

Abstract

Trimming operation of CFRP (Carbon Fiber Reinforced Polymer) high performance components is highly relevant to shape the final part geometry in aerospace industry. Nevertheless, due to the anisotropic nature of this composite materials and the high abrasiveness of the carbon fibers, machining of CFRP is usually accompanied by rapid tool wear and surface defects. Delamination, fiber pull-out or even resin overheating are some of the most common surface issues that can result in time-consuming and costly post-machining and in some cases leads to rejection of components. Therefore, the correct tool selection, cutting conditions and machining strategy plays an essential role. In this context, the present paper introduces a surface integrity study where the effect of different tool material (PCD and CVD-Diamond coated), tool geometry, fiber orientation and tool wear levels are analyzed. Trimming tests are performed in aerospace relevant HexPly® M21E/34%/UD134/IMA-12K material and the surface integrity is examined via optical microscope. The results of this study provide an important foundation for characterizing the material machinability and develop a process planning tool for the optimization of the machining procedure and tool selection to avoid surface defects leading to a significant increase in the quality of components.