Research On Drilling And Parameter Optimization Of Inconel 718 Laser Additive Forming Parts

With the development of complex,lightweight and integrated parts in aerospace industry,laser additive technology has been applied in the industrial field because of its advantages such as direct forming of complex parts and short forming cycle.The laser additive manufacturing method can directly form complex parts that cannot be formed by traditional machining,but the dimensional accuracy of the parts formed by additive manufacturing is low,so it is necessary to carry out machining before use to meet the requirements of parts use.Therefore,in order to improve the dimensional accuracy and forming quality of additive parts,Inconel718 laser additive parts were taken as the research object to carry out machining,and the influence of cutting parameters on the machining quality of additive parts was studied.The main contents are as follows:(1)Preparation of excellent Inconel718 additive forming parts.Firstly,Inconel718 alloy was coated on 45 steel surface in a single pass by simulation method,and the temperature field distribution of molten pool was analyzed to determine the range of additive parameters,and the additive simulation model was verified by experiments.Secondly,the prediction model of additive parameters and forming quality was established by laser cladding experiments based on response surface method.Finally,the additive parameters were optimized,and the additive forming parts of Inconel718 were prepared with the optimal additive parameters,which provided specimens for subsequent cutting.(2)Inconel 718 additive J-C constitutive model and drilling simulation analysis were established.Firstly,the J-C constitutive model of Inconel 718 was established by quasi-static tensile test and Hopkinson pressure bar test.Secondly,the drilling model of Inconel718 additive forming parts was established by Advant Edge software,the appropriate range of drilling parameters was determined,and the influence rules of spindle speed,feed rate,bit top Angle and spiral Angle on drilling axial force,torque and temperature were analyzed.(3)Drilling experiment of Inconel 718 additive forming parts.Firstly,the drilling experiment platform was built.Through the single factor drilling experiment,the experimental and simulation results were compared.The accuracy of the drilling model was illustrated by the error within the allowed range.Secondly,the macro morphologies,diameter errors and inner surface roughness of the borehole were measured and analyzed.Finally,the orthogonal experiment was designed with spindle speed,feed rate and bit top Angle as variables,and the drilling axial force and the roughness of the inner surface of the hole as the indexes to evaluate the machining quality.The range analysis was used for data processing,and the order of the primary and secondary influences of drilling parameters on the evaluation indexes was obtained.(4)Multi-objective optimization of drilling parameters.Firstly,the regression prediction model of drilling parameters,drilling axial force and inner surface roughness was established,and the significance of the multiple regression model was tested by variance method.Secondly,with spindle speed,feed rate and bit top Angle as optimization variables,and with drilling axial force,inner surface roughness and machining efficiency as optimization objectives,genetic algorithm was used to carry out multi-objective optimization of drilling parameters.Finally,the optimized results are verified by experiment.