Development Of Pin-on-disk Sliding Friction Coeiffcient Tester

At present, various types of friction tester are widely used on friction andwear testing. The select range for conditions of friction test is relatively wide witheasy to control influence factors. It can be used to do tests on more parameters withina short period and easy to find its regularity. Although there are certain differencesbetween working conditions and the simulated operation conditions of the plates, itstest results can be used to approximately estimate the real performance of the frictionmaterials under actual working conditions. According to the problems of complexsystem, relatively high cost and not good for conventional measurement etc. ofvarious coefficient friction testers currently, the pin-on-disk sliding frictioncoefficient tester integrating sliding friction device--signal acquisition input unit andcomputer systems based on basis of solid principles of tribology is developed.Based on the design schema, it developed the friction device of tester bydesigning spindle, testboard, loading mechanism and the optional purchase of drivemotor, governor, coupling and other components. The load cell and NI USB-6008data acquisition card were selected to build the data acquisition system. On basis ofreferenced a large number of documents, it designed an instrumentation amplifierwith functions of weak signal amplification, zero and the temperature compensation.It was used in the development of tester software according to the characteristics ofopenness, flexibility and low cost of the virtual instrument technology. Thedevelopment environment for the test system software is the LabVIEW software.The program realized the functions of the real-time input of distance, speed andpositive pressure values, the display of friction coefficient figures and text datapreservation etc.The developed tester is used to test friction coefficient of steel–Polyvinylchloride (PVC) and steel–Polycarbonate (PC) by changing the parameters of thethree influence friction factors--the positive pressure, load distance and the relativesliding velocity. Then it gets the conclusion that the friction factor in modern tribology theory is similar to influence on the friction coefficient, and obtained thesystematic errors and the uncertainty of the tester after the analysis of the test data.The measurement system analysis of the tester is done by using the three indicatorsof stability, bias and repeatability, reproducibility. It is possessed the conclusion: thecapacity of the tester meets the corresponding requirements, it possesses the requiredmeasurement capability basically, but the improvement is still required in the aspectsof the resolution and friction collection system etc.