Experimental Study On Stepped Drilling CFRP/Titanium Alloy Laminate

Due to the large difference in material properties between CFRP and titanium alloy,there are some problems in the process of making holes such as poor hole quality,inconsistent hole diameter and serious tool wear during aircraft assembly process.In order to solve the problem of multiple hole defects and serious tool wear when drilling CFRP/Titanium alloy laminates,this paper presents a method of drilling a CFRP / titanium alloy laminate with a step drill.In the paper,step drill was made and the drilling test of CFRP / titanium alloy laminates was carried out.The main research work of this paper is as follows:1.This paper chooses and calculates the size,diameter and geometric parameters of the ladder tool.Use the Creo to create a 3D solid model of the tool.The theoretical calculation is made on the axial force of the ladder tool drilling.The calculation results show that the ladder tool can indeed reduce the cutting axial force.Analyzed and calculated the double-sided parabolic chip flute chip removal performance of ladder tool.The drilling experiment of CFRP and titanium alloy plate was carried out to obtain the best cutting parameters of laminated materials,and analyzed the defects of stepped tool hole and the wear form of the step drill.2.The drilling experiment of CFRP/TC4 titanium alloy laminates was carried out by stepped drill.The cutting performance of stepped drill was studied compared with uncoated drill.The results show that stepped drill can effectively reduce the axial direction of drilling Force,reduce the hole diameter difference,improve the quality of laminated plate hole,but also improve the durability of the tool.3.In order to solve the problem of titanium alloy chips scraping on the wall of the hole and serious wear of the outer edges of the tool during the hole making process of the step cutter,Deform finite element simulation software was used to analyze the influence of the second main cutting edge on chip formation and tip temperature.On the basis of this,The drilling experiment of CFRP/TC4 titanium alloy laminates was carried out by change the inclination of the second main cutting edges of the step tool and the grinding of the outer edge of the tool,the results show that 45 ° edge inclination has the better cutting effect.In addition,blunting the outer edge of the drill can also improve the durability of the tool.