SELF LUBRICATING MATERIALS CAN HELP!
Either as an OEM making equipment, or as an end user, lubrication of moving parts is a major consideration – and ongoing cost – in the life of the equipment. Do you find yourself buying more lubricants than you should, or replacing “friction and wear” parts too frequently?
Grease is so ubiquitous that most people don’t even know the definition or composition. The ASTM definition of lubricating grease is: “A solid or semi-solid lubricant consisting of a thickener agent in a liquid lubricant. Other ingredients imparting special properties may be included”. Commercial grease usually consists of a thickener ( 5 to 35 wt %), base oil ( 65 to 95 wt %) and various additives (0 to 10 wt %).
Lubricants can be “natural” (petroleum-based) or “synthetic” (silicone, etc). There are four basic types: liquid (oil), semi-solid (grease), solid (Teflon® tape) or powdered (graphite or molybdenum disulfide powders). Once you start adding generic specialization, then each supplier’s “whiffle-dust” and a marketing plan, and you have literally thousands of options!
Yet with all this availability, over 50% of bearing failures are directly attributable to lubricant failure or contamination, as documented by Ernest Rabinowicz, an MIT professor for 43 years, widely known for his work in tribology, (study of friction and wear) and author of THE authoritative book “Friction and Wear of Materials”.
Professor Rabinowicz also documented that, on average, ~6% of the US GDP is spent on repairing damage from mechanical wear. In 2019, GDP was $21.5 trillion; 6% = ~$1.3 trillion!
Another consideration is the cost of delivering the lubricant to the wear surfaces –studies show that, on average, the application costs are 5X the cost of the lubricant itself – so, if the lubricant costs $2, the total cost to apply it is $10 – and that doesn’t include the costs in spills/clean-up, OSHA/EPA reporting, and other hidden costs that are usually buried in the maintenance budget.
Traditional metallic wear parts usually need frequent lubrication – what if you could reduce or even eliminate it?
How can you find a source that might help? You just did!
WS HAMPSHIRE provides industrial parts from many composite materials, both thermoplastic and thermoset, that have specially designed internal lubrication packages to address this problem. Some customers have been able to eliminate external lubrication entirely; many more have reduced the frequency and amount of lubricant, with our self-lubricating materials acting as a “safety factor” in case a lube system failure.
One example: an OEM of 125 ton mining trucks had a severe lubrication issue on the rear dump pivot bushings. Sealed roller bearings weren’t “sealed enough”, and grit got in and wore the rollers. Bronze would work, but required force-greasing 2X per day to flush out the grit (especially coal dust), that wore on the steel pin more than the bronze. They then extensively tested a solid lubricant filled cast nylon, which required no grease, and any grit that entered was simply buried in the nylon below the wear surface – problem solved and the thermoplastic solution cost less than the bearings or the bronze!
Give the pros at WS HAMPSHIRE a call – you’re in the right place!
Tom Connelly is a self-proclaimed ‘street engineer’ with over 40 years in the plastics industry.