Design Of A Micro Friction And Wear Test System Based On Silicon-Nickel Friction Pair

The working clearance of MEMS driving devices is small,the running speed is high and the working cycle is frequently.Compared with the traditional machinery,the friction problem appears to be more prominent,as a result,MEMS devices are susceptible to premature failure because of wear.Due to the lack of effective test methods of micro friction and wear,many lubrication methods and friction-reducing technologies cannot get further study.Therefore,a new type of micro friction and wear test system which can simulate high speed working conditions of MEMS driving devices has been designed in this paper.A micro friction device using ring-on-block friction pair has been designed.The device was mainly composed of micro load module,micro load measurement module,micro friction measurement module and rotary motion module.The function of applying micro load,measurement of micro load and micro friction,and the relative motion of friction pair were realized.According to the characteristics that MEMS devices fabricated by LIGA are mostly used nickel plating,millimeter silicon nickel friction specimen have been designed and manufactured in this paper.MEMS elastic beam and sensitive spring were also designed and fabricated for measuring small and micro friction load,Based on which,the micro deformation measurement system was constructed by laser measurement technology.In addition,according to the problem that many test rigs can not simulate the MEMS high speed and their low speed control precision,the servo motor was chosen to provide power for the relative motion of MEMS driving devices in this paper.And the servo motor closed loop control system and PID speed control system were designed to realize the precise control of speed.The software of test system was developed based on LabVIEW.It can control the speed of servo motor.At the same time,micro load and friction were collected respectively.Data was automatically processed and saved.Finally,the curves of friction-velocity,friction coefficient-velocity were generated.The test system was calibrated,according to the calibration results,the static characteristics of the test system were evaluated from three aspects: linearity,sensitivity and resolution.And the comprehensive performance of the test system was tested from the vibration of friction zone and the repeatability of test system.Finally,through the measurement of friction coefficient and the wear condition of friction pair,the lubrication effect of different viscosity lubricants on the surface of silicon-nickel friction pair was preliminarily tested.The results show that the micro friction and wear test system can meet the test requirements and measurements of micro load and friction in ?N level,which can be used in the research on micro friction and wear properties of MEMS devices.