Coolant Smell: Lubricant Solutions
to Prevent Rancidity
Rancidity – the chemical decomposition of fats, oils and other lipids - happens when bacteria, yeasts and mold multiply in metalworking fluids. The result is a bad coolant smell, diminished tool life, oxidation on the workpiece surface - and unhappy workers. Certain types of rancidity also cause metalworking fluids to darken and stain parts, and neutralize the rust-inhibiting characteristics of the fluid. Left unchecked, endotoxins, an illness-causing compound found in bacteria and other pathogens, make things even worse.
How does it all start?
A bad coolant smell can start when products are diluted for use (quality metalworking fluids manufactured in the US arrive free of microbial contamination) - also on weekends, when metalworking systems are usually shut down. The latter becomes a problem because aerobic bacteria consume the available dissolved oxygen, setting up a chain of events that leads to the distinctive odor of "rotten eggs."
It's not practical to eliminate all microorganisms from metalworking fluids, but you can keep them in check, prevent rancidity and coolant smell, and in the process, get the longest possible life from your coolant.
What are some specific suggestions?
Buy quality metalworking fluids from a reliable source. Don't risk your tooling, time and production on some No-name, Email Special-of-the-Day.
Get help. A credible suppler will test quality metalworking fluids in your systems so you can evaluate their performance, fluid stability, service life and cost. Suppliers can also help with water-related issues. Common water components like calcium, magnesium and phosphates all contribute to rancidity; water hardness also has an impact. Fortunately, all of this is manageable.
Before each charge, clean machines, reservoirs, and lines using a good machine cleaner. This will eliminate the sludge, fines and oil that attract microorganisms.
Never use reservoirs for trash disposal.
Monitor concentration and pH. While too high a concentration is just wasteful, too much dilution deprives your systems of the full benefit of the fluid's inherent rancidity control. To maintain optimum concentration, consider using a premix station or proportioning device to mix water and fluid to the right concentration. The pH of a diluted metalworking fluid should be between 8.8 and 9.2 to maintain rust protection properties and prevent rancidity.
Aerate at least intermittently, to keep all areas of the system in motion, and less susceptible to microbial attack
Keep sumps in good condition by preventing lubricating fluids from leaking into water-based coolants.
Get to know an Acculube metalworking fluids expert. We have experience with every major type of metalworking fluid and machining system. We're eager to share ideas on how you can get out of trouble fast - and make adjustments in product, additives, or process that will serve your shop - and your wallet - in the long term.
Talk with Us Today Acculube's lube experts are the best source for information about coolants and oils, and how to use them to your best advantage. Call us today! Contact Us: 1.800.404.2570 or email us at sales@acculube.com
