Research On Free Abrasive Assisted Electrolysis Finishing For Blades Of Difficult-to-Process Materials

High-speed abrasive particle flow-assisted electrochemical hybrid processing is a surface finishing method in which a certain volume fraction of abrasive particles is mixed with conventional electrolyte for surface polishing.By combining the grinding action of abrasive particles with electrochemical action,the surface roughness of the workpiece can be further reduced,the bumps and dimples of the surface can be removed,and the surface integrity of the workpiece can be improved.It is difficult to directly process difficult-to-machine materials because of high hardness of surface,while the introduction of electrolysis can increase the processing rate.By forming a passive film,the abrasive particles loss can be reduced and the abrasive particles life can be increased.This article focuses on the high-speed abrasive particle flow assisted electrochemical hybrid processing technology for difficult-to-machine materials.The main research contents include:(1)The processing mechanism of the hybrid machining is analyzed.Based on Faraday's law and tribology theory,the material removal formula of the hybrid machining is derived.By analyzing the polarization curves of the two materials under different electrolyte concentrations,the effect of abrasive grains on the processing current,and comparing the difference in the oxygen content on the surface of the workpiece processed by different abrasive grains,it is proved that there is a passivation phenomenon in the hybrid machining process,And abrasive particles help to remove the passivation film produced by electrolysis.(2)A device used for Flow-abrasive Assisted Electrolysis hybrid Finishing was built.A fixture for basic experiment was designed.The fixture is used for two kinds of liquid flushing methods,90°positive punching and 0°side punching.Three positive punching cathodes with single hole,array 4holes and array 9 holes were designed.The processing effects of different flushing methods are analyzed and compared through simulation and experiment.The results prove that the array porous cathode design is conducive to improving the uniformity of current distribution on the workpiece surface.Compared with forward punching,the side flushing method is more conducive to improving the surface integrity of the workpiece.(3)Through the single factor test,the influence of different factors such as processing voltage and abrasive grain size on the processing effect was analyzed,and the surface quality of the workpiece was improved through parameter optimization.Setting the processing voltage at 5V,electrolyte of 10%Na NO₃,a machining gap of 1mm and processing with 1200 mesh abrasive particles for 5 minutes,the surface roughness Ra of SS304 stainless steel can be reduced from the initial 0.4?m to 0.083?m.Setting the processing voltage at 1V,electrolyte of 10%Na NO₃,a machining gap of 1mm and processing with 1200 mesh abrasive particles for 5 minutes,the surface roughness Ra of the TC4 titanium alloy can be reduced from the initial 0.4?m to 0.092?m.(4)Through power function analysis and quadratic polynomial analysis,the surface roughness Ra value and removal quality of the workpiece after hybrid processing are predicted.The results prove that the quadratic polynomial analysis has higher prediction accuracy,and based on this,an empirical model of surface roughness value Ra and removal quality with respect to processing voltage,processing time and processing gap is established.(5)The fixture for blade machining was preliminarily designed,and the simulation analysis was carried out according for the different liquid inlet methods and machining gaps at the intake side and exhaust side.The simulation and test results show that:when the liquid is flushed from the intake side and the exhaust side for 5 minutes,and the processing gap is 3 mm,the processed blade surface has good uniformity,the black oxide on the surface is effectively removed,and the local surface is rough The degree Ra value decreased from the initial 0.578?m to 0.154?m.