Study On The Cutting Performance Of Titanium Alloy Assisted By Laser Heating And Micro Lubrication

Titanium alloy has good corrosion resistance,high strength and relatively low density,and is used widely in aerospace,biomedical,automotive manufacturing and other fields.The surface quality of the workpiece after traditional machining is poor,and tool wear is serious.Although cooling assisted cutting and heating assisted cutting can improve surface quality,both have their own limitations.To solve this problem,a machining method combining cooling assisted cutting and heating assisted cutting is proposed in this paper,that is,micro lubrication combined with laser heating assisted cutting.The main research contents and important conclusions of this paper are as follows:(1)Basic experimental study on dry cutting of titanium alloy.Using VB and Ra as evaluation indexes,the effects of cutting speed v,the depth of cut αp,feed rate f and other process parameters on cutting performance are analyzed.The parameters range of cutting speed v,the depth of cutαp and feed rate f are determined by single factor experiment of dry cutting titanium alloy.The cutting speeds v are 25m/min,45m/min and 65m/min;The depth of cut αp are 0.2mm,0.3mm and 0.4mm;The feed rate f are 0.1mm/r,0.15mm/r and 0.2mm/r.(2)Experimental study on micro lubrication cooling assisted cutting of titanium alloy.Taking tool flank wear VB and workpiece surface roughness Ra as evaluation indexes,the main technological parameters of micro lubrication assisted cutting are optimized by orthogonal test and response surface analysis,and the technological combination of cutting speed v,the depth of cut αp,feed rate f and MQL pressure p are obtained.MQL assisted cutting can improve surface quality significantly.SEM and EDS analysis show that serious abrasive wear and bonding wear exist on the tool surface in MQL cooling assisted cutting.(3)Laser heating simulation and experiment.Firstly,the finite element simulation of laser heating temperature field is carried out,and the influence law of laser parameters on temperature field is obtained.Secondly,Taguchi orthogonal test is designed to perform laser heating assisted cutting on titanium alloy.The results show that the surface quality of the workpiece is improved obviously after laser heating cutting,but the VB wear of the tool surface is higher than that of the MQL assisted cutting,because the high power laser beam softens the workpiece but also reduces the stiffness of the tool,and the chemical properties of titanium alloy are active,so the tool surface is prone to chemical reactions.SEM and EDS analysis show that laser heating assisted cutting could inhibit the abrasive wear on the tool surface,but adhesive wear still exist and some parts of the tool surface are damaged.Compared with MQL assisted cutting,oxidation reactions on the tool surface of laser heating assisted cutting are more active.(4)Experimental study on micro lubrication combined with laser heating assisted cutting of titanium alloy.Taking tool flank wear VB and workpiece surface roughness Ra as the main evaluation indexes,the effects of cutting speed v,feed rate f,laser power P and micro lubrication pressure p on the combined auxiliary cutting performance are analyzed through the design and range analysis of Taguchi orthogonal test.The results show that the combined cold and hot auxiliary cutting can improve the surface quality and reduce tool wear greatly.According to the tool SEM and EDS analysis,the tool wear is reduced significantly,and there is no abrasive wear on the tool surface,only slight adhesive wear.