Theoretical And Experimental Research Of Drilling CFRP With Complex Helical Drill

Carbon fiber reinforced plastics(CFRP) are characterized by lightweight and stiffness-to-weigh ratios, high fracture toughness and good heat resistance. They have been widely used in airplanes, chemical machinery, communication and transportation, sport equipment and textweave, etc. But there are many questions in drilling CFRP because of the characteristic itself, the most frequent defects are delamination, fiber pull-out, inter-laminar cracks and thermal degradation after drilling, drilling is the most commonly applied method in conventional machining, accounting for as much as 40% of all materials removal processes. So drilling of CFRP has been taken as an important subject in the research field of machining.According to the difficulty of machining CFRP, carrying out drilling CFRP with complex helical drill. The main works have been done as follows:(1)Development overview of dill was introduced and improvements on structure and material of current dill were made a summary. Drilling CFRP with complex helical drill was put forward, and introduced the advantage of complex helical drill in drilling CFRP.(2)The differences of normal helical drill and complex helical drill was introduced. The mathematic model of complex helical drill was given according to the principle of grinding drill points, and the "S" type of chisel edge was analyzed carefully.(3)The main defects when drilling CFRP were introduced, and discussed why the delemation generated when drilling CFRP with twist drill from establishing the model of drilling force. At the same time made the method of hole quality assessment.(4) According to mading the single factor experiment, and analyzing the effect of delemation in different geometrical parameters, and confirming the optimal geometrical parameters from discussing.(5)The effects of technological parameters on the qualities of holes were studied from making orthogonal experiment, and then confirmed which range of technological parameters should be used when drilling the CFRP.