Microbial issues in your shop carries a high cost. We’ve pointed out that metalworking fluid makes up 2% of your spend, but affects 80% of the labor performed in a typical shop. Biologicals in your MWF can be a plague on your budget and consume profits, causing harm to equipment directly (via corrosion, clogging filtration and pumping equipment, etc.) and by affecting the quality of machining.
Consider this example: An outage in a 10,000 gallon central feed system can cost a shop $50,000 to $100,000. First, treatment of the resulting waste will cost $0.25 to $3 per gallon, and disposal will cost $0.50 to $3. Then there’s the labor to clean and recharge the system, plus the cost of new MWF. Then add lost production as machines sit silent.
Biological activity also changes MWF’s chemistry, reducing its effectiveness. That means more waste, damage to workpieces, and other problems that drive the per-piece cost up. Infestations affect operator acceptance as well, causing Monday morning odors and increasing the likelihood of dermatitis as the pH level of the MWF changes. If biological contaminations are not prevented or handled, you can end up with a machine that delivers less fluid than it should, is the wrong chemistry, and harms the operator.
As you can see, even the most vigilant anti-biological program is a cost saver. So who is our enemy, and how do we defeat them?
We have good news and bad news. The bad news? There are about five decillion (5 followed by 33 zeros) bacteria in the world, and none of them belong in your MWF. The good news? You only have to worry about two kinds: Aerobic bacteria, which need oxygen to live, and anaerobic, which don’t. And facultative anaerobes, which can do both. And also fungi, yeasts, and molds. Did we say that was good news? Sorry.
Steps to Handle Biologicals
Our enemy is numerous, stealthy and multiplies quickly. But beating them requires relatively simple, common-sense practices.
- Vigilance in testing – A robust testing program with solid baselines will provide a number of benefits for your shop, one of which is early detection of biological problems.
- Prevent contamination – Foreign substances like spit, food particles, personal waste or any other organic material can introduce bacteria into your MWF and give them food to eat.
- Prevent tramp oil contamination – Even if you’re using a biostable MWF (such as our NuSol® line), tramps contain carbon compounds that provide rich food for bacteria.
- Use the right mix – Ensure you have the recommended concentration when mixing MWF for initial filling and makeup. Water sources can introduce bacterial contamination, so use the purest water you can.
- Keep the machines clean – Frequent cleaning not only removes biologicals, it eliminates items that allow them to grow unhindered (such as chips and swarf) or feed (such as tramp oils and organic contaminants).
- Kill them all, let waste disposal sort them out – If you do experience an infestation, you can deploy a number of weapons to destroy it, including radiation, light, sound (i.e., ultrasonic cleaning), heat, or chemical biocides. In some cases, you can also eliminate them through additional filtration. Your MWF distributor should be an excellent resource to help you choose the right method for your situation.