Many machine operators–and even facility managers–are surprised to realize that bacteria can breed in industrial fluids and coolants. Dave Semersky, an expert with 40 years experience in industrial fluid control and purification, has seen operators regularly make simple mistakes that greatly increase bacterial growth, driving up costs and drastically lowering production. If you used to get 1,000 parts out of a drill bit, and now you’re getting 400, you need to consider what might be thriving in your coolant.
How Bacteria Damages Industrial Coolants
Just like fines and tramp oil, bacteria are contaminants: their presence alone changes how your coolant performs. However, in contrast to something inert, like particulates, bacteria can actively break down your fluids.
For example, most coolants have both water and oil components. These fluids use emulsifiers to force the oil component of the coolant to form droplets of a precise size. This allows the coolant to penetrate appropriately, and reach the surface where the cutting tool is removing metal. Many bacteria attack these emulsifiers. When they do, the fluid becomes less stable, and the oil droplet size begins to vary. As that oil droplet gets larger, it not only fails to reliably reach its destination, but the coolant as a whole ceases to work as well: It doesn’t cool, wet, or lubricate as expected. This leads to lower production, poorer part quality (especially in terms of surface finish and size control), increased rejection rates, decreased tool performance, and decreased tool life.
Bacteria flourishing in your fluids can also create environmental health and worker safety issues. “If a fluid has high bacteria counts and your hands are in it,” Semersky explains, “you can have irritation of the skin. And you are certainly going to get foul odors.”
In short, a little bacteria can grow to be a big expense.
Fluid Control to Limit Bacterial Growth
“The people that manufacture good metalworking fluids are making products as bio-resistant as possible,” Dave Semersky reminds us.
But that doesn’t make your coolant impenetrable to bacteria.
“There needs to be an education of operators,” says Semersky. “So they don’t spit tobacco in the sump or throw their peanut butter sandwiches down there. It sounds ridiculous, but all of that’s been done. All of that’s caused problems.”
Even if you eliminate spit and lunch scraps, “you still need to regularly filter out tramp oil and the contaminants that leak in. Even those are a food source for bacteria. Removing them makes the fight against bacteria much easier. Keep the environment clean, the machine tool sumps clean, run the fluid at a proper concentration so it is as bio-resistant as it should be. It’s always the case that clean fluids work better and last longer.”
As a rule: Clean fluids work better and last longer. Contaminated fluids simply don’t.