Basic Research On Application Of CVD Diamond Coated Solid WC-Co End Mill

Chemical vapor deposition (CVD) diamond coating can significantly increase the tool's cutting performance in machining difficult-to-machine materials. The thesis aims at the deposition process of CVD diamond coating on solid WC-6%wt Co end mill and the cutting performance of CVD diamond coated mill for machining high-silicon aluminum alloy. The main work and results are as follows:1. The control scheme of a miniature EACVD system for diamond film deposition was determined according to the characteristics and operating requirements of diamond deposition. On this basis, a set of hardware and software were designed to control the temperature, gas flow, gas composition and bias voltage automatically, what laid a solid equipment foundation for diamond deposition on solid cemented carbide end mill as well as other substrates.2. Three-dimensional models were created to simulate the flow field in the miniature EACVD system for diamond coating deposition on cemented carbide end mill for the first time. The finite element simulation result shows that the flow field could meet the requirement of diamond deposition when the end mill is placed on the substrate vertically. The effect of inlets distribution on gas flow field uniformity was researched and an optimization distribution of gas inlets was obtained for CVD diamond coated tool batch deposition.3. The ultrasonic-aided-two-step pretreatment method for solid cemented carbide end mill was developed for the first time. The effect of pretreatment process on the tool erosion was investigated. Deposition experiments were done to research the effect of CH4 concentration and deposition duration on the surface morphology of CVD diamond coating on different positions of the end mill. The CVD diamond coated solid WC-6%wt Co end mills were prepared successfully.4. Experiment of dry-cutting high-silicon aluminum alloy was done to test the wear performance of the prepared CVD diamond coated end mill tools. The roughness of workpiece surface and tool wear form were studied in detail. The results show that the prepared CVD diamond coated end mill could meet the needs of dry-cutting high-silicon aluminum alloy.