Surface Roughness Prediction Model And Experimental Study Of GH4169 In Short Electric Arc Milling

SEAM(Short Electric Arc Milling)technology has effectively solved the problem of processing extra hard,super strong and high red hard materials such as nickel-based superalloy,and has gradually been applied to high-end manufacturing fields such as aerospace,shipbuilding,national defense science and industry.At present in view of the short arc milling research mainly uses the process experiment method,and the arc discharge is instantaneous in a tiny space,complex changes in the process of traditional experiment method is difficult to observation,the micro corrosion mechanism has not yet been fully revealed,therefore this article through the establishment of short arc milling single pulse and random temperature field simulation model of consecutive pulse,the influence law of interelectrode arc energy on the surface morphology of discharge pits was analyzed to reveal the forming process of workpiece surface morphology and predict the surface roughness.Firstly,through four stages of material removal,the energy sources in the ion channels between poles were analyzed,and the physical model of short arc milling was established.The energy distribution between poles was captured by monopulse experiment,and the appropriate heat source and discharge channel radius were selected to perfect the model,and then the loading boundary conditions were solved.Secondly,the time-varying forming process of the discharge pits is revealed by monopulse simulation.With the expansion of the ion channel,the energy diffuses on the surface of the workpiece,and the internal energy is transferred in the way of heat conduction,finally forming the shallow bowl discharge pits.The control variable method was used to analyze the variation law of melting depth and melting width with inter-electrode energy,and the variation law of melting pool depth-diameter ratio.The size of the melting pool was positively correlated with voltage and duty ratio,and negatively correlated with frequency.To simulate random pulse discharge in a row,this article through the transverse and longitudinal respectively applying random function simulation of arc workpiece position uncertainty,rough surface of the workpiece forming process simulation,along with the arc continues to load,the surface electric erosion pit gradually increased,and there is no rule of random arrangement,the same location or the adjacent area will be affected by multiple arc thermal erosion,The outer circular part of the original electric erosion pit was destroyed,and the morphology of the electric erosion pit was not kept intact.The influence of interpolar energy on surface morphology was analyzed by changing several groups of electrical parameters.The section contour of the simulation workpiece was extracted by the method of image recognition.The middle line of the contour was fitted by Matlab,and the surface roughness was calculated to analyze the morphology change rule.Finally,a short arc milling experiment was carried out to analyze the relationship between the surface morphology and different electrical parameters.The microstructure of the workpiece surface was established by the ultra-depth of field microscope,and the surface morphology composition of simulation and experiment was compared and analyzed.The surface roughness of the workpiece was extracted and compared with the predicted results,and the relative error coefficient was calculated,which fluctuated around 17% overall.The error sources were revealed from recasting layer,droplet anti-adhesion,electrode loss,etc.The best error coefficients were fitted by the interior point method,and the relative error was reduced to less than 3%,which verified the rationality of the model and provided a certain theoretical basis for the research of short arc milling.