ISO TR 8285:1990 pdf free

ISO TR 8285:1990 pdf free.Plain bearings一Evaluation of the tribological properties of polymer-based materials
This Technical Report deals with the tribological testing of bulk plastic specimens under specified working conditions, i.e. load,sliding velocity and temperature, without lubrication. From the tost results, data are obtained about the tribological behaviour of steel-plastic rubbing pairs which can be used in practice for predicting the working capacity of a friction unit.
It specifies the test conditions, equipment and programmes that allow reproducibility of the results at particular conditions of the specimen preparation and testing.
This Technical Report specifies the specimen shape, conditions of the rubbed surfaces of the plastic and steel, tolerable run-out of the rotating counterface, heat transfer between the device housing and counterface, the range of variations in the friction process parameters in order to reach the reproducibility of the
results in the tribological testing of plastics. It proposes technical solutions for the standard equipment usod for the tribological testing of plastics.
Testing according to this Technical Report may be carried out with block-roller devices presently available. They need to be modernized and some technological limitations have to be observed to ensure the reproducibility of the results.The technological limitations are as follows.
The comparative tests should be carried out with a heat-insulating bushing between the test shaft and roller (see figures 4 and 6)， The heat dissipation will improve the reproducibility of the test results obtained with equipment of different designs.
The certification tests shall be carried out with thermally regulated rollers (see figure 5) or a multistep device with a ther-mally regulated shaft (see figure 7). The thermostatic regu-lation is done to estimate the tribological properties of plastics at a constant counterface bulk temperature.
The continuous control of the linear wear is realized with a special instrument with an accuracy of±0,5 um the use of such an instrument cuts the testing period of the specimens after running-in (see figure 6).
To measure average temperatures of the plastic and metal fric-tion surfaces, a thermocouple is located within a through-hole in the plastic block 0,2 mm above the friction surface.
At the stage of thermostatic regulation, the required bulk temperature of the roller and the shaft in a multistep machine is controlled by variations in the operating conditions of the liquid thermostat.ISO TR 8285 pdf download.