| Carbon fiber is heat-resistant, light-weight, high-strength, high-modulus and its proportion is one-fourth of iron while its strength is more than ten times of iron, which makes it a very special material. Because of those good properties of carbon fiber, people mix carbon fibers with other materials like resin, metal or ceramic to get composites which are more light-weight and high-strength, called carbon fiber reinforced composite(CFRC). CFRC materials are now widely used in aerospace industry, like rockets, missiles, large aircrafts and chemical machineries, vehicles, bridges, roads, sport equipments, textiles and medicine tools.Because of the special structure and physical properties, the traditional processing methods are gradually unable to meet the processing needs. Except delamination, glitches and tearing during processing, there are also other defects, like severe tool wear, larger cutting force and higher cutting temperature, which make the tool life shortened. In addition, material removal mechanism of carbon fiber composite is different from ordinary metal materials and it is difficult to ensure good surface quality by traditional surface processing. The cutting fluid shall not be allowed in most of the carbon fiber composite materials'machining, and without cooling and chip removal effect, there would be a further deterioration of the processing conditions. It's more difficult to guarantee the surface quality of the workpieces.To solve the machining problems of carbon fiber reinforced plastics (CFRP), an ultrasonic assisted grinding system was designed in this paper. Some researches were carried out about processing performance of the ultrasonic assisted grinding of materials. The main work and results are as follows:1. The ultrasonic assisted grinding test platform was set up. According to the test requirements and the conditions of processing, the ultrasonic generator and the ultrasonic structure devices were designed, including the transducer, horn, and tools; then the static stiffness and radial pulse of the ultrasound system were measured, and also frequency and amplitude of the ultrasonic vibration. Based on self-designed vertical drilling and milling machine, ultrasonic devices and three-dimensional dynamometer were installed to complete the preparation for the experiments.2. This paper presented the researches on the contrast experiments between ultrasonic assisted grinding and traditional grinding about the grinding force and surface qualities. The disciplines were obtained that how the grinding force changed with variation of parameters such as the ultrasonic amplitude, grinding force, spindle speed, feed rate and grinding depth. Compared with the traditional method, the grinding force could be reduced by 50% at most in the ultrasonic machining. The surface roughness was also reduced by 10%-30%.3. This paper also presented a preliminary study of the processing mechanism of ultrasonic assisted grinding. By observing the tool blocking, surface morphology and debris morphology of ultrasonic assisted grinding. Compared with the traditional machining, the difference between the two methods was investigated.4. The CFRP material processing experiments of ultrasonic assisted grinding was designed, and different process parameters (amplitude, depth of cut, spindle speed, abrasive size, etc.) were chosen to finish the orthogonal experimental studies. The best parameters were obtained by optimization and obtained the best surface whose Sa was 1.154μm and Sq was 1.678μm.
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