Solid lubricating coatings tribological test rig development

Solid lubricant coatings are commonly used under difficult operating conditions. Compositions containing graphite and molybdenum disulphide are the most used worldwide. Friction and wear tests are carried out to evaluate solid lubricant quality. Tribological properties are characterised by friction coefficient. The following paper presents the design of a ball-on-disc scheme testing rig. The normal load is applied by weights and remains constant during the entire testing time. The sliding speed is controlled by computer and changes smoothly. A strain gauge is installed to friction force determination. The sensor provides direct measurement of the bending strain and also the torque. The latter to be reduced for higher accuracy. To evaluate the design stiffness and contact point displacement the finite element analysis was done. The test rig is developed in accordance with ASTM G99.