| Diamond-coated carbide drawing dies as a new type of drawing tool has been concerned by many scholars and engineers, and shows a great application prospects and market potential. However, there are always some problems to solve in the deposition process, which impedes the large-scale application of the diamond-coated drawing die, especially for the large aperture ones. In this paper, by using hot filament chemical vapor deposition method, the application of diamond films on large aperture drawing dies has been studied. The main research work are summarized as follows:1. By using finite element analysis, the temperature field distribution of drawing die is studied. At the same time, technology parameters of hot filament (including the number and radius of hot filament, distance between hot filament and inner wall of drawing die, the diameter of drawing die) and its influence on substrate temperature field distribution are analyzed. Finally, technology parameters of hot filament are optimized.2. Based on the lows of inner-wall temperature field distribution, I have designed two different arrangement of hot filament for the large aperture drawing dies, including the arrangement of rotary U-type hot filament and the arrangement of spiral type hot filament, which provide a reference to application of diamond films on the large aperture drawing dies.3. Through contrast experiment, we studied the main process parameters (concentration of carbon source and deposition temperature) in the actual deposition process, analyzed the influence of process parameters on diamond-coated comprehensive performance, and optimized the process parameters.4. In order to satisfy the requirements of the practical application of drawing, ensure the drawing precision and surface quality of copper tube, and reduce the surface roughness of the diamond films, we use ultrasonic polishing technology to polish the diamond-coated surface and analyze the polishing results. |
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