Experimental Research On Drilling And Milling Of C/SiC Composites

Carbon fiber/silicon carbide ceramic (C/SiC) composites is a kind of continuous fiber reinforced ceramic matrix composites. It’s not only high specific strength, high specific modulus, low thermal expansion coefficient and other excellent properties, but also has high temperature resistant, low density, wear resistance and high-temperature chemical stability, etc. In addition to possess high specific strength, high specific modulus, low thermal expansion coefficient and other excellent properties, it also has high temperature resistant, low density, wear resistance and high-temperature chemical stability. In addition, it’s not sensitive to crack and not easy to break characteristics. It is widely used in such as thermal protection components, aerospace aircraft, turbine engine nozzle, thermonuclear fusion shields and high speed braking systems. When the C/SiC composite materials have been processed, it’s easy to produce processing defects such as burr, laminate, edge breakage, delamination. It’s a typical difficult-to-machine materials. Currently in use of C/SiC composite components are mostly after the performing, before the heat treatment processing into required shape and size in advance, in order to avoid or reduce the material forming the problem of secondary processing, but in practice is difficult to avoid the secondary processing of materials. Especially the joint of C/SiC composite components and other materials component requires a lot of holes and key way to machine.This paper combined the research cooperation project which is carbon fiber/sic composite materials processing technology development, with Dalian University of Technology and a domestic aerospace companies. The research objects in C/SiC composite materials, aims at the choice of the hole and the milling cutter and typical defects causes and evaluation and the optimum processing scheme and the optimum technological parameters for exploratory research.The main research contents and results were shown as follows:(1) For the C/SiC composite materials, the typical processing defects and evaluation in drilling and milling is proposed. The cause of machining defects is analyses.(2) C/SiC composite materials were drilled by ordinary high-speed steel cutting tools, ordinary carbide cutting tools, PCD cutting tools and metal bond electroplated diamond tools respectively. Drill processing quality of different cutting tools is contrast. Then the best drilling cutting tool was selected to mill C/SiC composite materials. Then USES the single factor test and orthogonal test methods, drilling of PCD cutting tool C/SiC composite materials research, drilling research mainly include:the hole quality of PCD cutting tool system, cutting parameters and cutting force impact on the quality of making hole drilling, the selection of process parameters, PCD cutting tool wear and durability.PCD cutting tool system hole number is at least four times that of ordinary carbide cutting tools. Finally, try to take advantage of spiral milling approach for the C/SiC composite materials large size hole is difficult to processing, the processing problem of poor economic benefit of making hole exploratory experiment was carried out, and its feasibility is proved.(3) C/SiC composite materials were milled by ordinary carbide cutting tools, resin bond corundum tools and metal bond electroplated diamond tools respectively. Mill processing quality and cutting tools blockage of different cutting tools is contrast. Then the best milling cutting tool was selected to mill C/SiC composite materials. Electroplating diamond tool was used for milling trial test on C/SiC composite materials. And the influence of different process parameters on milling quality is analyses. Combining with the cross cut test results, The burr area size of different fiber directions were analyzed, then the effect on the surface quality of fiber direction during milling process was studied.