Cutting Characteristics in End-Milling of CFRP with Diamond-Coated Herringbone Tool

Abstract

Because carbon fiber-reinforced plastics (CFRP) is used for various parts, it requires cutting. However, CFRP is well known to be difficult to cut. In this study, two types of tools were used to trim CFRP. At first, a conventional shaped tool was used. The cutting forces on the CFRP were measured and the influence of the fiber orientation relative to the cutting direction was investigated. Next, a herringbone-shaped tool was used and compared with the conventional end-mill. Specifically, cutting forces, burr formation, and surface roughness were measured to characterize the effect of this tool position. The characteristics of a diamond-coated tool were also investigated. The effectiveness of the diamond-coated herringbone tool was clarified. The main results obtained are as follows: 1) Cutting forces change by changing the tool axis position of the herringbone tool; the tool axis position is an important cutting condition. 2) By choosing the appropriate tool axis position, no uncut carbon fiber remains on the cut surface of the CFRP with the herringbone tool. 3) The burr formed under down-cut milling is smaller than that of up-cut milling at the cut end of CFRP by using the herringbone tool. 4) Small debonding of the diamond coating occurs on the cutting edge, but the wear value is very small, and the shape of the cutting edge is maintained despite small debonding of the diamond coating. 5) Diamond particles on the cutting edge do not work as those for grinding do. Sharp cutting edges with large rake angles and relief angles can cut the carbon fibers cleanly.