Research On Micromachining Mechanism And Experiment Of The Key Part Of Inertial Navigation

With the development of aerospace technology,inertial navigation devices have become increasingly demanding.Dynamically Tuned Gyroscope(DTG)has been widely used in inertial navigation devices because of simple structure,superior performance characteristics.Flexible joints are key component of flexible gyroscope to make up flexible support,whose manufacturing precision will have a direct impact on gyroscope performance.Flexible joints’thin reinforcement can get a high size,shape,surface quality precision by micron processing.Through simulation and experimental study of highly elastic alloy’s fine grinding processing mechanisms,this paper explored different process parameters’ impact on the grinding force,thermal,residual stress to provide a theoretical basis for the actual processing.The research of the contents and conclusions are as follows:Firstly,largest single grinding grain undeformed thickness model was constructed by software ABAQUS,single grinding grain residual stress simulation model was built by software Advantedge,and grinding process parameters were designed with the goal of getting high processing quality and efficiency.Changed the wheel speed in constant efficiency,and the simulation results indicated that the grinding surface appeared compressive stress.The improvement of grinding wheel speed made the compression force reduction resulting in a corresponding decrease of compression layer depth,at the same time,the reduction of thermal effect depth resulting in the tensile stress decrease;increase cut depth could improve metal removal rate,but the grinding force,the thermal residual stress were increased.Because the change of residual stress are more sensitive on wheel speed than cut depth,during the optimization of process parameters,high speed should be considered firstly and then increased cut depth appropriately,which could get both high quality and efficiency easier.Secondly,the accuracy of the workpiece surface quality as the main objective,and the processing efficiency as a secondary objective,to optimize and analysis the process parameters.Taking into account that the limiting speed would reduce spindle lifetime,then appropriately reduced the speed to ns = 10000rpm.It could be accepted because stress range just increased 9.8%and it was almost the same with limiting speed.When cut depth ap = 3μm,stress range increased by 14.7%than ap=1μm,but the efficiency increased 3 times.Therefore,select ns =10000pm,ap = 3μm in actual processing can achieve the unity of quality and efficiency.Thirdly,by fine boring process simulation and analysis to explore the cutting speed,depth of cut,tool rake angle and clearance angle’s impact on the cutting forces,heat,residual stress,emphasized on the distribution of residual stress,obtained after processing the elastic alloy by carbide alloy tools residual stress distributed in a curve,in high speed cutting surface appeared tensile stress and surface appeared compressive stress in low speed cutting,subsurface maximum compressive stress occurs,the process parameters influence on residual stress in order of the degree was depth of cut,cutting speed,tool rake angle and clearance angle.Finally,built the experimental platform of micro-machining project,did grinding experiment with different process parameters,analyzed the grinding force under different conditions and the integrity of workpiece surface quality,and the results were compared with the simulation analysis.