Differential Counting And Position Analysis Of Microscale Wear Particle

When the mechanical system is working,wear particles dispersed in the lubricating system will be generated.And it will contaminate the lubricating oil.As the working time of the lubricating system increase,degree of the mechanical wear increases.This will result in a decrease in the service life of the mechanical system.The detecting technology of wear particles can be used to detect and analyze the abrasive particles in the lubricating oil,and provide some guidance for the mechanical system diagnosis.In this paper,the most of the wear particles in lubricant oil were micron scale in size.Therefore,the detecting technique with a high-precision used for analyzing micro scale particles was a research focus in the field of microfluidic technology.In order to effectively suppress the system noise signal,a differential microelectrode was designed for detecting wear particle based on the differential detection principle.At the same time,the analyze software was used to analyze the response performance of the model to current for different frequencies and different detection particles.Traditional technologies were employed for fabricating microelectrodes with many disadvantages,such as complex processing,high-cost,high-requirement on processing equipment and long time consuming.In this study,a method of microelectrodes fabrication with robust performance was proposed.Through the research on the processing technology of microelectrode,two factors affecting the processing quality of microelectrode were obtained: the surface characteristics of the inner wall of the microchannel;and melting metal flows continuously in the microchannel.In this study,polystyrene(PS)microspheres with good surface homogeneity were detected and analyzed firstly.Based on the differential detection chip designed in this study to count polystyrene microspheres with particle sizes of 10 μm and 18.5 μm respectively.Custom threshold filter were used to process the detection signal,and the number and concentration of particles were obtained by calculating the number of detection pulses.By the sheath flow method,the particles were controlled to focus on a specific position in the microchannel,and the detection was performed.Thus,the relationships between the pulse amplitudes of the current signal and the position of the particles were obtained.It was determined that the feasibility of this method,and it can be applied to detect of iron powder particles.In this study,based on the results obtained from the particle counts and position detection of polystyrene microspheres,the particle concentration detection and position analysis for the particles with equivalent diameter of 10 μm and 15 μm were carried out.The particle concentration calculated by volume density method was used to determine the accuracy of particle concentration detection.And the detection current signal was analyzed to obtain the position information of the particles in the microchannel.And it could provide some guidance for the detection of metal abrasive particles in oil.This paper studied the differential detection and the position analysis of metal wear particles in lubricant oil.This method can be used to further improve the detecting accuracy of abrasive particles,and expand the application of complex shape particles detection in oil.