Study On Low Damage Mechanism Of Drilling Glass Fiber Reinforced Plastics

With the further improvement of drilling quality in aviation industry,further research is needed on low damage mechanism of drilling glass fiber reinforced plastics.It is necessary to study the low damage behavior and corresponding mechanism in drilling glass fiber reinforced plastics,and the main contents are as follows:(1)In the case of a round holes array backing plate and a square hollow backing plate as support,theoretical analysis and experimental research of drilling glass fiber composites with traditional twist drill are carried out to analyze the mechanism of support plate to reduce or suppress exit delamination damage.The main mechanism of supporting is that it provides enough support for hole,making the thrust force pushing behavior maintain steady,and there will not be sudden increase of delamination damage.(2)Ten candlestick drills and one traditional twist drill are selected to drill glass fiber composite materials,so as to study the mechanism of low damage drilling with the candlestick drill.During the drilling process with the candlestick drill,the relative smooth and easy fiber cutting behavior of the outer drill tip,combined with weaker exit thrust force pushing behavior,make the drilling quality of the candlesrick drill significantly better than that of the twist drill.(3)Experimental research and finite element analysis of drilling glass fiber composites with three candlestick drills and one traditional twist drill are carried out to study what kind of candlestick drill structure can has its unique low damage drilling behavior.The drilling quality of candlestick drill is closely related to the drill tip structure of candlestick drill.When avoiding 180° outer drill tip angle and keeping outer drill tip angle greater than 180°,increasing the outer drill tip angle,the rake angle of outer cutting edge and the clearance angles of outer cutting edge cutting are conducive to strengthening fiber cutting behavior of the outer drill tip,and weaken the exit thrust force and corresponding pushing behavior,so as to improve the drilling quality of the candlestick drill.