Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1378657
AS I SEE IT Jim Fitch | Noria Corporation Deciphering Important Visual Features of Wear Particles When working from a single sample, it is common for labs to classify wear particles according to standardized shapes such as platelets, chunks, ribbons and spheres. e task of deriving meaning from the number and size of particles in the different classi- fications is much more difficult. Condition monitoring is not about science — it's about understanding and reporting what is happening, why it's happening, where it's happening and how severe or threatening the condition might be. is can be a daunting task, to say the least. The lubricant co-exists with the machine and has an active presence in its critical frictional zones. As such, the progression of wear-related machine failures does not go unnoticed by the lubricant. e byproducts of wear and surface damage become suspended in the lubricant, embedded in the filter or stratified as sediment in nooks and crannies. As failure advances, most wear modes produce more particles, and some also produce larger particles. In certain cases, what was thought to be an advanced failure state may suddenly appear benign or in decline. ere are reasons for this, so do not be fooled. e wounds and excavations from wear do not heal over on their own. e time has come to increase the specificity of wear particle char- acterization. e four basic shapes were a good start, but there is much more we can learn and apply. For those who understand vibration, imagine being limited to vibration overalls or only what is produced in the low-frequency velocity spec- trum. Likewise, thermal imaging has shown us how to look far beyond discrete temperature values or trends. is analogy applies to wear debris analysis as well. e appearance of particles holds many clues that generally go unnoticed or are just not understood. The Characterization of Particles (ASTM D7684) Any good tribologist will tell you that real failure modes rarely conform to strict theoretical models — rather, they are more complex and are usually the combination of many contributing factors and conditions. ere are exceptions — for instance, it is easy to recognize the shapes from cutting wear and normal rubbing wear — but that's basically where the simplicity comes to an end. Understanding chunks and platelets requires closer examination Condition Monitoring, Lubricant Analysis and Troubleshooting Learn More: noria.com/ascend/ Factor: A8M – Condition Monitoring, Lubricant Analysis and Trouble- shooting Training Level: Management and Training(M) Stage: Condition Monitoring, Lubricant Analysis and Troubleshooting About: The overall degree of plant reliability varies in proportion to team education on condition monitoring, lubricant analysis and trouble - shooting topics. More about this ASCEND ™ Factor 4 | May - June 2021 | www . machinerylubrication.com