Tribological Evaluation of a Graphite Coating Using a Custom Miniature Conveyor

Abstract

Reducing friction in conveyor systems has significant economic and environmental implications, as a substantial portion of energy losses originates at the belt-bed interface. This thesis outlines the design, construction, and validation of a miniature conveyor tribological test system. Unlike conventional tribometers, which impose concentrated point contacts, the miniature conveyor replicates the distributed load consistent with industrial conveyor systems. It can measure real-time mechanical responses of steel samples coated in a low friction coating. The mini conveyor was validated by evaluating three materials: uncoated mild steel, PDA/graphite coated steel, and Polytetrafluoroethylene (PTFE). Electrical power, temperature, sound, and acceleration were recorded. Electrical power results for the uncoated and PDA/graphite coated samples showed minimal differences under the current testing conditions, while the PTFE samples exhibited decreasing power consumption due to PTFE transfer onto the belt during extended testing. Sound, acceleration, and temperature measurements demonstrated the system’s sensitivity to subtle mechanical changes. Temperature proved to be the most consistent indicator of frictional behavior, with the uncoated samples showing the highest temperature rise while the PDA/graphite coated samples showed lower changes in temperature. Coating wear was assessed using 3D confocal microscopy, revealing nonuniform wear along the samples, suggesting uneven load distribution during testing. Overall, the results confirm the conveyor system’s capability to distinguish material behavior and pick up on minute differences in conveyor health during operation. This work provides a foundation for future studies involving prolonged testing, increased loading conditions for accelerated wear, and improved mechanical stabilization to enhance measurement reliability and tribological insight