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16/12/2022 News

Pausing production for Christmas? Don’t let microorganisms multiply in machine fluids and spoil your New Year re-start

As the festive season approaches, many precision manufacturers and their staff will be looking forward to a well-earned break. But those planning to shut down their operations over Christmas would be wise to take precautionary measures before they go, to minimise the risk of microbiological growth in water-based cutting fluids while production is paused causing major problems in the New Year. 

Metalworking fluids (MWFs) are vital to operational efficiency and human and environmental health: reducing heat and friction, removing chips and dirt, and protecting machines and processed materials. Therefore, it is essential to maintain optimal conditions of use at all times – or risk serious consequences for workers’ health.

Why do machine shutdowns create a fertile environment for microorganisms to grow?

But when it comes to water-based MWFs, machine downtimes can be detrimental to fluid health, safety and longevity, because continuous flow and aeration are required. The operating temperature of MWFs already creates an ideal environment for many microorganisms to grow, and stopping the machinery exacerbates this by causing the fluid to stagnate. A range of other factors can contribute to the exponential spread of organisms, including: using non-sterile water to dilute the cutting fluid, dirt in the sump, contamination of fluid and equipment, and tramp oils (carried from previous processes or leaked from hydraulic of slideway oil) forming a film on the surface which prevents aeration.

What are the consequences?

There are many potential consequences from microorganisms spoiling a metalworking bath. These include metal staining, or possible corrosion of metal parts if the pH drops. The emulsion can lose viscosity or become unstable, meaning that it becomes a less effective lubricant. Pipework and filters may become blocked. The fluid life could be reduced and cleaning, maintenance and waste disposal costs could increase. In addition, a bad smell and a variety of adverse health effects could result.

What can be done to prevent problems?

Taking the following steps prior to shutting down should ensure that problems like this don’t occur over the festive period:

  1. Check the pH of all metalworking fluids and increase it by 1-2% more than the specification level to provide better protection. 
  2. Check the bath’s bacteria content using the dipstick method. Use ACTICIDE 14 at 0.005%-0.025% if contamination is found above 10³. For long-term shutdowns, especially for the central tanks, adding bactericide to the bath is also advisable. Ask your supplier to guide you. 
  3. Remove tramp oil and circulate coolant systems daily to allow aeration. If it is not possible to turn the pump on, drop an air hose into the bath to provide movement to the fluid. Keeping the skimmers on is strongly recommended.
  4. Remove as much of the chips and swarf that settle at bottom of the fluid tank as possible.
  5. Take a sample to analyse fluid conditions once you restart production. The Anac Indus oil analysis tool offers soluble fluid checks and expert diagnosis.
  6. Consider taking this opportunity to clean the system if it has already exceeded a certain sump life, has ineffective filtration set up or the tank is too small. If the bath is near the end of its operational lifetime:
  • Drain the coolant tanks but do not rinse them.
  • If using Folia, spray the inside machine with a 10% strength solution.


  • Drain, clean, and spray with a Rust Preventative solution.
  • If using Folia, spray the inside of the machine with a 1% strength solution instead of a Rust Preventative solution.
  • On returning after the Christmas break, fill the system with the new coolant.

Ensuring a smooth-running New Year

These preventative actions should minimise MWF exposure to harmful microorganisms and result in cost savings.  Choosing the right product in the first place is just as important to ensure that MWFs perform optimally. Selecting a user- and environmentally-friendly product that offers a pictogram-free solution, while maintaining high pH stability to preserve the integrity of the fluid and resist the formation of contamination, will secure both high performance and safer working conditions.

TotalEnergies’ new Spirit X series and revolutionary Folia series deliver on all these fronts, providing outstanding resistance to bacteria and fungi growth.

Learn more about TotalEnergies’s range of metalworking fluids, or our expert Songul Facey on [email protected] for more information.