The graphite material has the characteristics of ablation resistance, thermal shock resistance and so on. It is used in the long tail nozzle of air to air missile, and is the main material for the structural parts of the engine throat. The requirements of the parts size and appearance of high technology, but because of its special material, cutting performance, processing quality, especially in the easy processing of edge collapse defects, these have become a bottleneck of non metal processing.
In recent years, various types of engines, long tail nozzle, graphite parts processing tasks heavy, high technical requirements. Based on the analysis of the scrap graphite parts for the past year, it is found that the scrap produced by the part of the workpiece is about 20%., because the material is difficult to be machined and the processing efficiency is low, which makes the production progress of the parts seriously affected.
In order to solve the problem of edge collapse graphite parts as soon as possible, improve the production efficiency of graphite parts, based on a certain type of air-to-air missile, and the front thimble throat component shell combination and other mechanical processing as the research object to conduct technical research, explore the Shi Mocai material processing technology from the aspects of processing method, cutter and its cutting parameters, solve the problem of machining parts of compacted graphite. Non metal processing technology, has important significance for scientific research and production tasks successfully completed.
Cubic boron nitride is prepared by high temperature and high pressure. The material is a kind of six party boron nitride with a similar structure to graphite. Compared with synthetic diamond, this material has a lower hardness, but it has good thermal stability. It is suitable for processing ferrous metals and difficult to process materials. Cemented carbide has higher hardness and better wear resistance, but it is hard to sharpen the blade. Therefore, three kinds of cutting tools, such as synthetic diamond, cubic boron nitride and cemented carbide, are chosen for cutting comparison. In order to choose the appropriate cutting parameters corresponding to the three cutting tools, a thorough cutting test was carried out: Due to the speed limit of the machine itself, the linear speed of cutting can be between 130m/min~150m/min.
In summary, we can see that:
(1) the machining of graphite parts adopts diamond cutting tools, the processing effect is better, and the durability is the highest.
(2) graphite material should be processed with low speed, small feed, cutting parameters, roughing and finishing methods, not only can prevent the collapse of the edge, but also more conducive to improving tool durability.
(3) the method of "parallel cutting" can guarantee the surface quality of parts and improve the processing efficiency.