Study On Precision Polishing Process Of Abrasive Flow In The Base Of Mass Flow Controller

The inner hole of the mass flow controller is the key to its performance,and its processing precision and quality requirements are higher.The Seven-star Qualiflow Electronic Co.LTD in Beijing found that some kinds of micro holes can not meet the required surface quality while polishing materials for stainless steel inner hole of the series mass flow controller by abrasive flow polishing process,because of the unreasonable selection of abrasive parameters and processing parameters.Therefore,the abrasive flow polishing technology for the inner hole of the base was studied,a method for selecting suitable parameters was proposed,and processing parameters for abrasive flow polishing were optimized and partical processing technology was improved to make the quaility of the hole to achieve the accuracy requirement.In view of the present situation that abrasive parameters selection in the process of abrasive flow polishing mostly rely on experience,the multiple goals optimization model of abrasive parameters was established.The model considered the effects of all parameters comprehensively and it can be used to determine the most suitable abrasive parameters of various kinds of pores in different working conditions.In order to get the suitable machining parameters for different holes,the numerical simulation of fluid flow was used to simulate the flow state of fluid abrasive in the straight hole of base around the abrasive flow polishing process.The relationship of inlet pressure with aperture and depth was found through the control variable simulation.And its correctness was validated by experiments.The principle of determining of polishing process parameters with the variation of pore diameter and pore depth was determined.Aiming at the problem that the quality of the inner hole of the mass flow controller can not meet the quality requirement,the major reason was analyzed by numerical simulation method,on the basis of this,two sets of fixtures with shaft core are designed,and the processing flow of the stepped hole is optimized,The problem of abrasive flow polishing in the step hole is solved.The feasibility and rationality of the fixture are verified by numerical simulation and experiment.