Advanced cutting tools for edge trimming of carbon fibre reinforced composites (CFRP)

Abstract

The use of carbon fibre reinforced polymers (CFRP) has transitioned towards applications with large-scale manufacturing with specific desired material characteristics, such as in the aerospace and automotive industries. Despite being manufactured in a near-net shape, machining of CFRP is often necessary to meet dimensional tolerances. The requirement to improve both the processing capability and production cost is heightening given the challenging cutting operations of CFRP, with common issues arising such as machining-induced delamination, poor surface finish and increased tool wear. Sharp polycrystalline diamond (PCD) tools are often employed during CFRP milling, however these are not economically practical due to their high cost, geometric construction limitation and inherent weakening of their geometry (due to relative low toughness and very sharp edges), leading to decreased tool longevity. Sharp diamond-coated carbide tools represent a cost-effective alternative to PCD tools. A novel approach is presented utilizing a high-thickness HF-CVD (Hot-Filament Chemical Vapor Deposition) diamond coated carbide milling tool, with laser sharpened edges, which was used for investigating the effect of coating on cutting force and surface quality of fibre reinforced composites. This paper is an introductory exploration of laser sharpened tools, focusing on their durability and performance. Instrumented experimental tests in contour milling operations demonstrated the increased cutting performance for achieving well-finished surfaces, with negligible rounding of the coated cutting edge. Future studies will compare these tools with standard PCD coated tools without laser sharpened edges to evaluate their relative advantages in machining applications during extensive tool wear tests, when machining abrasive materials, such as CFRP.