Study On The Improvement Of Ti6A4lV Titanium Alloy Gun Drilling Technology For Small Diameter Deep Hole Drilling

In this paper,aimed at the common problems in deep hole drilling such as low processing efficiency,poor processing quality,difficulty of chip removal and serious tool wear,the hard working material of Ti6Al4 V titanium alloy was studied by using gun drill as cutting tool.The mechanical model of gun drilling was established.The influence of two main factors,cutting parameters and geometric parameters,on hole machining quality was studied,and the wear and failure modes of the tool were analyzed.The main tasks are as follows:1.Based on the idea of differential element integration,a gun drilling model including cutting parameters,tool geometry parameters and mechanical properties of materials was established using Ti6Al4 V titanium alloy as the research material.On the basis of the existing model,the model coefficients were modified under various cutting conditions,and the integral area of the cutting edge was enlarged.The eccentricity at the bottom of the drill groove was taken into account in the integral area of the cutting edge.Simultaneously,the torque calculation was simplified reasonably according to theoretical analysis.On the other hand,the drilling model is verified and analyzed by experiments using ? 17 mm and ? 8mm gun drills.2.Using Ti6Al4 V titanium alloy as workpiece material,two typical hole drilling experiments of ? 17 mm and ? 8mm were carried out.The effects of feed rate and cutting speed on cutting axial force,chip morphology,surface roughness and aperture deviation were analyzed by variable parameter test.The optimum cutting parameters of two kinds of aperture were given.For chip analysis,considering the practical operation and the measurability of data,the chip compression ratio(CCR)was proposed as the index to measure chip deformation,and the influence of cutting parameters on chip deformation was analyzed.3.Taking ? 15.1mm gun drill as an example,the wear and failure modes of tool during deep hole drilling of Ti6Al4 V titanium alloy material were studied.The tool wear curve was drawn,and the influence of tool wear on cutting force,chip morphology,surface roughness and aperture deviation was analyzed.Based on this,it was put forward that the maximum wear volume of the first rake face was an important reference for gun drill regrinding.4.Based on the study of drilling model and tool wear of gun drilling,taking the ?17mm gun drill as an example,the influence of tool geometry parameters on cutting force,chip morphology,surface roughness and aperture deviation was studied by selecting the outer edge angle of gun drill as a single factor variable.The optimal tool geometry parameters for gun drilling of Ti6Al4 V titanium alloy material were given.