Research On Defect Inhibition And Technology In Drilling Of Aeronautic Materials

In aircraft assembly, good drilling quality is an important guarantee for aircraft structural part with long life and high reliability, therefore, it is very important to study the inhibition of hole defect in drilling of aeronautical materials positively. With the flourish of the aviation manufacturing industry in our country and the unceasing enhancement of aircraft parts assembly automation level, at the same time, in order to adapt to manufacturing requirements of the new generation aircraft and improve the quality and efficiency of the aircraft assembly, the hole making technology for aircraft parts assembly based on industrial robot has been widely used, and the precision hole making technology for aeronautical laminated material remains to be seen to break through, in this article, some technology problems on the system of aviation materials hole of research, the main research content is as follows:(1) The drilling exit burr formation mechanism of metal material is expounded, the interlayer burr formation and the relationship with interlayer gap are analyzed in detail, the interlayer gap formation mechanism in drilling stacked materials is analyzed, the interlayer gap model is built through mathematical analysis and finite element simulation, the relationship between the theoretical interlayer gap and the interlayer burr height is obtained, a interlayer burr height inhibition method through reducing interlayer gap is put forward, and it is verified through drilling test with preload.(2) The formation mechanism of exit delamination in drilling composite materials is analyzed, that thrust force is the main factor influencing the exit delamination is observed, and the exit delamination can be inhibited by reducing the thrust force. Based on linear elastic fracture mechanics, theory of plates and shells and the law of conservation of energy, the drilling critical thrust force for exit delamination in drilling composite material with ordinary twist drill is produced, and the model is effective through experiment verification. The empirical formula of drilling thrust force of CCF300 composites is established through experimental work, the critical feed is put forward, which is verified in the experiment, and the composite exit delamination suppression method based on altering process parameter is put forward.(3) Based on the carrier of industrial robot, experimental study on drilling CFRP/aluminum alloy stacked materials using twist drill and three pointed drill with different geometric parameters is conducted, the thrust force curves of twist drill and three pointed drill, as well as the material function mechanism in transition area of stacked plates and the change of thrust force are analyzed, the influence law of the cutting tool and process parameters on the thrust force and hole diameter is obtained, the aluminum alloy exit quality different tools is compared, and the cutting tool parameters and process parameters are optimized.