Study Of Abrasive Flow Machining Simulations And Experiments On Inner Hole

Parts with tiny internal hole,e.g.fuel nozzles and precision valves,play an important role in the fields of aerospace and medicine,however,the fine and long features of the tiny internal hole structure lead to the problems of difficulty to polishing,low polishing efficiency,and poor polishing quality.Efficient polishing has always been a difficult point in its manufacturing.In this paper,By virtue of the characteristics of good processing accessibility of abrasive flow processing,researches are carried out for the inner hole polishing to solve the problem of high quality and high efficiency polishing.Firstly,the horizontal pneumatic abrasive flow polishing test platform is built,and the special sealing fixture for the micro-parts of the abrasive flow processing is designed,with two kinds of typical inner surface flow passages in the micro hole polishing extracted.On this basis,the finite element simulation model of abrasive media flow is established,the velocity field and pressure field in the flow channel are calculated,and the effect of the joint action of pressure field and velocity field on the polishing effect of the inner hole surface is studied by Preston equation,provided for the subsequent experimental studies.Furthermore,H62 copper material is selected for the abrasive flow processing,and the surface quality parameters before and after processing,height parameters and spatial parameters are analyzed.The amplitude-frequency feature extraction is carried out by analyzing the initial surface texture of the inner surface,and the abrasive grits of different particle sizes are selected for the preparation of the graded abrasive.The corresponding inner-hole abrasive flow processing of the copper tube was carried out to study the initial surface formation of the abrasive flow processing,and elimination of texture and the effect of newly formed texture on surface quality.In addition,the effect of the abrasive grade on the inner surface in abrasive flow polishing is investigated.The characteristic spectrum is extracted by Fourier transform,and the effect of abrasive flow polishing on the surface of the inner hole is studied under different mixing particle size(60#,120#,W28)ratios,revealing evolution of the workpiece surface texture under different abrasive grit size levels,and the preferred abrasive media grading abrasive particle strategy is explored.