Research On Structure And Parameter Optimization Of Deep Sub-millimeter-scaled Textured Tools For Titanium Alloy Machining

As a concrete embodiment of green manufacturing strategy implementation,dry cutting technology has become one of the research hotspots in the machining field.With the development of aerospace industry,which constantly puts forward new requirements for the manufacturing industry,titanium alloys have been widely used in all kinds of integral complex structural parts with the increasing amount due to their excellent comprehensive properties.In order to realize the high efficiency and high performance machining of these aerospace titanium alloys,rapid tool wear mainly caused by the severe friction and high cutting temperature in the cutting zone is still the key problem to be solved.With good anti-friction,anti-adhesion functions and improved wear resistance,high performance surface texture brings new research directions for reducing the friction at tool-workpiece and tool-chip contact surfaces and improving tool cutting performance,which is of great significance to conserve resources,protect the environment and reduce costs.Aiming at the problems of rapid tool wear,very low efficiency and poor quality of machined surface in titanium alloy processing and the difficulty in mass production of existing micro-/nano-textured tools,the design scheme of deep submillimeter-scaled textured tools was proposed and the exploratory research on the application of these tools in dry cutting of Ti-6Al-4V was carried out in this article.Specific work and the results achieved are summarized as follows:（1）The cutting performance of the tool with friction-reducing grooves was investigated during dry turning of Ti-6Al-4V in terms of cutting forces,average friction coefficient on tool-chip interface and chip morphology.Compared with the non-grooved tool,this kind of friction-reducing grooves can reduce cutting force and improve the friction performance of tool surface only under the matched cutting conditions.Therefore,the structural parameters of these friction-reducing grooves need to be improved.（2）The design scheme of deep submillimeter-scaled textured tools was proposed,with different texturing types and parameters designed on the uncoated cemented carbide flat inserts.By simulation method,the performance of these textured tools was investigated.The analysis of finite element structural strength simulation shows that the implantation of these surface textures on rake faces had almost no effect on the mechanical strength of the inserts.Using cutting simulation,the cutting performances of these textured tools were studied,and the effects of texturing parameters such as groove width,depth,and the distance from the first groove to the cutting edge,and groove spacing,on the tool cutting performance were analyzed,and at last,these structural parameters of surface textured tools were optimized.（3）Nine kinds of deep submillimeter-scaled surface textured inserts were fabricated,and the influence of these textures on cutting performance was investigated during dry turning of Ti-6Al-4V.The cutting performance of these tools was evaluated in terms of cutting forces,chip morphology,coefficient of friction at the tool-chip interface,tool wear and surface roughness.The results show that the implantation of these textures on the rake face can improve the tool cutting performance,and the mechanism can be explained by the interaction between the reduction of tool-chip contact surface and the immersion of chips into grooves or pits and the ploughing effect.Among all the textured inserts,the parallel type P01 shows the best performance in reducing cutting force,improving the friction properties on the rake face and the tool wear resistance.At the same time,the reasonable surface texture on the tool rake face is helpful to improve the anti-adhesion performance of the tool,and thus improve the machined surface quality of the workpiece.（4）Based on the results of cutting simulation analysis,seven groups of optimized surface texture parameters were obtained,and the cutting performance of these optimized tools was verified by simulation and cutting tests.Finally,the cutting performance of these optimized textured tools filled with solid lubricant MoS₂ was investigated for further performance improvements.The verification results show that compared with the insert P01,the optimized textured inserts N1^N7 show better performance in reducing the cutting forces,improving the friction performance on the rake face and enhancing the wear resistance.