Surface Morphology Of Carbon Fiber Composites In High Speed Cutting

Carbon fiber composite’s excellent characteristics made it widely used in the areas of aviation,construction, automotive and some other areas, surface morphology and tool wear had been vacant by now when high speed cutting CFRP. In addition, because of its excellent performance, the coated cemented carbide tool and poly diamond tool were widely used in mechanical manufacturing field. Therefore, in this paper, using carbon fiber composites as experimental material, systematically analyzes the surface roughness, multi fractal and tool wear morphology when high speed cutting CFRP using coated cemented carbide tools and poly diamond tool, finally provides theoretical and practical support for tool materials selection, cutting parameters selection and optimization.In this dissertation, analytical and experimental studies were conducted with carbide tool、diamond tools and coated tools (TiN, TiN/Al2O3/TiCN) in high-speed milling CFRP. Based on the milling experiment, the influence of cutting tool materials and cutting parameters on the surface roughness, multifractal and tool wear of machined CFRP and it’s mechanism were studied, surface roughness prediction mode was established by regression analysis method, the cutting parameters were optimized, the tool wear mechanisms and cutting surface defects were in-depth analyzed.According to the influence degree, the influence rules of cutting parameters on surface roughness were cutting speed the most, followed by feed rate, depth of cut the minimum. Cutting speed had a highly significant impact and feed rate and depth of cut had obviously affected to surface roughness of CFRP. With the increase of cutting speed, surface roughness decreased. The feed rate’s influence to surface roughness of all tools had a critical value, the surface roughness decreased when it less than critical value, the surface roughness increased when it larger than critical value, while it got minimum surface roughness if the feed rate was equal to critical value. When the depth was small, it got a high surface roughness. Due to rapid wear of carbide cutting tool, the noise was large and surface roughness changed greatly after cutting speed over 320m/min, so it was not suit for high speed cutting CFRP. PCD tool’s surface roughness was decreased with the increase of cutting depth while other tool’s surface roughness had some fluctuation. During the whole experiment, PCD tool showed excellent performance.The empirical model of PCD tool high speed milling CFRP could evaluate surface roughness in some degree, but it also existed some deviation between theoretical value and experimental value.To analyze and calculate the multifractal parameters of CFRP by using the multifractal theory,and it indicated that the spectral width and spectral difference had a close relationship with the CFRP’s surface. In the process of high speed cutting CFRP, through the tool and material surface morphology analysis found that CFRP’s special properties made it was prone to fiber fracture、delamination、drawing and other defects and the most serious wear area was near the cutting edge of former flank, flank of all tools also existed some wear area. Carbide tool’s flank wear area changed greatly while coated tools appeared bonding phenomenon and PCD tool’s wear area was smallest and uniform.