The Formation Mechanism Of Disfigurements During Drilling And The High-efficiency Techniques Of Drilling C/E Composite

Being one of advanced materials, carbon fiber reinforced plastics (CFRP) is characterized by lower weight, lower expansion coefficient, higher strength-to-weight and stiffness-to-weigh ratios, excellent anti-thermal shock ability and good vibration absorption, which now have been widely used in airplanes, spaceships and automobiles etc. There are a lot of holes that need to be machined when using CFRP, especially when the component of CFRP is riveted with other components. However, CFRP is a typical difficult-to-cut material due to the anisotropy and the low strength between layers. There are several problems such as disfigurements, severe worn of tool, low-efficiency and environment pollution etc. during drilling CFRP.Carbon fiber reinforced/epoxy matrix (C/E) composite is taken for studying in this paper. The effect of the fiber orientation, the drilling force, the cutting heat and the cutting parameters, etc. on the drilling disfigurements is explored during drilling C/E composite, concerning about the mechanism and formation factors of drilling disfigurements and the high-efficiency drilling process technique. The high speed numerical control grinder GM1000 for revolving member is developed according to the grinding tool with electroplated abrasives and its new drilling process. The digital machining technology of C/E composite comes true by use of the grinder. The main contents and the academic achievements in this study are shown in the following:(1) The characteristic of drilling disfigurements is concluded through the observation of the drilling damages around the hole; A cutting model of single fiber is built up based on the orthogonal cutting model of C/E composite, and the removal mechanism is analyzed; The formation mechanism of disfigurements is explored by the fly milling study of monolayer carbon fiber, and the effect of tool type and cutting speed on the cutting quality is studied; The distribution model of disfigurement at the exit is summed up.(2) The regulation of drilling force is discussed during drilling; The effect of the thrust force on the drilling disfigurements is studied through the evaluate factors of delamination, avulsion and burrs; The temperature of the cutting area is simulated by use of manual heating, and the effect of cutting heat on the cutting quality is explored through the fly milling study of monolayer carbon fiber; The regulation of the drilling heat is studied by use of manual heating and variation of the drilling parameters. (3) The new grinding tool with electroplated abrasives and drilling process is developed by focusing on the severe worn tool and the disfigurements. Compared to the carbide twist drill, the superiority of the new tool is verified. Reasonable parameters are gained through the experiment of the drilling temperature and the thrust force.(4) The high speed numerical control grinder GM1000 for revolving member is developed according to the grinding tool with electroplated abrasives and its new drilling process. The digital machining technology of C/E composite comes true by use of the "small cutting depth—high feed rate-multilayer cutting" process, the processing regulations of the digital machining is built up.The formation mechanism and the effect of the drilling force and the cutting heat on the drilling disfigurements is explored in this paper. The satisfied quality and efficiency of machining is gained through developing the grinding tool and its machining process. The digital machining of C/E composite comes true based on the numerical control grinder GM1000 and its processing regulations.