Development Of The Cutting Tools For CFRP And Research On Machining Technology

Carbon fiber reinforced plastics (CFRP) are characterized by superior strength-to-weight,specific modulus, stiffness-to-weight ratios, and they possess a large number of advantages, such aslow thermal expansion coefficient, high fatigue strength and anticorrosion, etc. They have been usedwidely in airplanes, spaceships, national defense, industry and sport equipment, etc. Drilling andgrinding of CFRP are conventional technologies in the process of installing fasteners on the CFRPcomponents, but it’s hard to guarantee the machining quality. CFRP is a kind of typicaldifficult-to-machine material because of its characteristics such as high strength, high hardness, andanisotropy.According to the difficulty of machining CFRP, several special cutting tools for CFRP have beendeveloped here. Correlative experiments have been finished to evaluate these tools’ machiningperformance and analyze the effect of the processing techniques on the machining quality. Theoptimal cutting parameters according to the drilling tools and grinding tools have been selected. Themain works have been done as follows:(1) Based on the idea “design and manufacture the cutting tools according to the materials”,referring to the standard of the aircraft industry, the tools’ precision has been proposed. The methodsof controlling the precision the CFRP holes machined by the brazed diamond core drills have beeninvestigated in this thesis. The approaches of designing the tools’ matrix and the manufacturingprecision have been obtained and the experiments showed it is correct.(2) The effects of the cutting parameters on the qualities of CFRP holes’ entrance and exitmachined by the brazed diamond core drills. The optimal drilling parameters have been proposedwhen using brazed diamond core drills to drill CFRP. And the experiments showed that under theformer optical processing techniques the zero-fault holes can be obtained.(3) The drilling process of the brazed diamond core drills when machining CFRP has beenanalyzed. Considering it is very difficult to center the hole and remove the chips, a new drilling tooloptimized for CFRP has been developed called “A drilling tool for composite material with thefunction of centering and chips removing” which can compensates the conventional brazed diamondcore drills. Experiments has been finished to verify the new tools’ function and it showed that thenews tools can achieve the plans and good machining quality has been obtained.(4) The grinding experiments on CFRP using the brazed diamond grinding tools have been carried out in this thesis. The effects of the rotate speed, grits’ size and the distance between two rowsof diamonds on grinding quality have been analyzed. The optimal grinding parameters when using thebrazed diamond grinding tool to machining CFRP has been proposed in the theses. And the optimalprogram about designing this kind of grinding tools.