Application of surface replication combined with image analysis to investigate wear evolution on gear teeth - A case study

Gear wear is a critical degradation process in many applications and its monitoring is important to ensure safe operation of machines. The case study presents a novel approach to obtain comprehensive and high-resolution wear information for monitoring the evolution of gear wear. This is achieved through the combination of a moulding method and non-contact imaging-based measurements in two- and three-dimensions and without gearbox disassembly and tooth removal. Optical and laser scanning confocal microscopy and image processing tools were employed to provide quantification of surface roughness, wear severity and wear depth on gear teeth during a lubricated endurance test. Also, a detailed qualitative analysis on the progression of the two main wear mechanisms (abrasive wear and fatigue pitting) was provided, alongside an evaluation of the diagnostic capabilities offered by the proposed methodology. The insights on gear wear offered in this case study also represent a valuable guideline for researchers and engineers in the field of gear condition monitoring. Moreover, the proposed wear analysis technique can be used to characterise and understand wear phenomena in other conditions and geared transmissions.