Study On The Thrust Force And Tool Wear For Carbon Fiber Composites With Carbide Drill

Carbon fiber reinforced plastics(CFRP) have been widely used in the aerospace, automobile industry, sports entertainment and other fields, because of it is characterized by light quality, high modulus, high strength and high abrasion. CFRP is a kind of difficult-to-machine material. Its characteristics such as laminated structure and anisotropy make CFRP is easy to produce tear,delamination, and the surface accuracy is difficult to ensure in machining process. High hardness, low thermal conductivity and high strength of CFRP easily lead to tool wear and failure, that will have a great impact on processing cost and effciency.In this paper, According to the problem of tool wear in machining T800, the experimental studies on the relationship among tool wear,drilling force, drilling temperature and hole quality, provide a reference for tool development and processing parameters. The dissertation includes the following aspects:(1) The YG6 X carbide twist drill have been used in the T800 carbon fiber composite plastics drilling experiment. This thesis has analyzed the drilling process of twist drill, the variation of the processing parameters and tool wear with the drilling axial force was investigated. Through modeling the critical delamination force when twist drill processing T800 have been ascertained. We established the drill axial force of twist drill model by using multiple linear regression analysis method. The results show that the largest impact on drilling axial force is speed, followed by feed rate, the last is processing hole number,with the increase of tool wear, the drilling axial force increased.(2) Through Taguchi experiment studied the influence of the cutting parameters and processing hole number on tool wear. It turned out that feed speed is the biggest influencing factor for the twist drill flank wear value VBmax, then is the number of holes, and the smallest is spindle speed, the three contribution rate of S/N are the 44.17%, 31.75% and 24.08%. With the increase of tool wear, the cutting temperature increased. The main mechanism of tool wear is abrasive wear. The main wear area of the twist drill is the place of chisel edge regrinding and the main cutting edge. We established the tool wear of twist drill forecast model by using multiple linear regression analysis method.(3)The thesis has observed the morphologies of hole-wall, the circular degree of hole and the roughness of hole-wall after twist drill drilling processing. Discussed the reasons why the defects of holes’ entrance and exit generated in twist drill drilling process.The relationship between tool wear and hole quality have been studied. Analyzed the influences of outer corner wear to the roughness of hole-wall. The results show that with the increase of tool wear, the roughness of hole-wall and the delamination area factor, the circular degree of hole decreased.