While there are many factors that affect the life of a cutting fluid, such as dilution control, tramp oil, top up rates etc. the key to ensuring maximum sump life from any fresh fill is machine cleanliness.
During use, machine tool fluid systems become contaminated with tramp oil machining debris, hard water soaps etc. which can be found on the sides and bottoms of tanks. These deposits are ideal breeding grounds for both bacterial and fungal infections and eventually become “biomasses” that can shorten fluid life.
It is therefore essential that when any particular fill of cutting fluid has been identified as reaching the end of its effective life, that the system is thoroughly cleaned and disinfected. Simply pumping out and re-filling is not a cost effective alternative to this recommendation.
Even where cutting fluid condition appears to be good, with no oblivious symptoms of degradation, good working practice dictates that fluid systems benefit from annual maintenance which minimises the risk of unplanned downtime and ensures safe working conditions for operators.
As with most jobs preparation is paramount when cleaning a machine tool. Prior to commencing the job it is a good idea to ensure the following:-
- There is sufficient capacity of containers to hold the waste.
- Replacement filters are available where required.
- The appropriate volume of Machine Tool System Cleaner is available.
- There is sufficient volume of fresh fluid available to re-fill and top up the system.
- Appropriate PPE equipment is available
- Introduce the appropriate machine tool cleaner, at the advised dilution ratio, into the old cutting fluid, first ensuring the system is full so that the machine cleaner contacts all surfaces of the tank.
- Allow this to circulate for 8-10 hours (4 hours minimum). A good machine tool system cleaner allows the machine to remain in production during this cycle.
- Switch off system and remove tank covers and the swarf conveyor where possible.
- Brush down the interior of the machine and remove debris
- Drain out the old fluid using a vacuum pump or similar. Always work from the fluid surface to avoid leaving a film of tramp oil on the surface of the tank.
- Physically remove any solid debris from the tanks and conveyor.
- Remove and clean, or change, any filters.
- Rinse the system with clean water filling to the minimum level.
- Circulate this rinse water for a few minutes then pump out until dry.
- Replace conveyor and tank covers.
- Refill with fresh Cutting Fluid and circulate immediately, catching the first few litres of the flow as this will be rinse water.
If you need any further help or advice please contact ROCOL, a UK Cutting Fluid Manufacturer.