Lubricants specialist ROCOL, part of multi-national group ITW, provides market-leading cutting and lubricating fluids, delivering high performance solutions to meet the needs of any machine shop.
Here, ROCOL explains how to clean a machine tool, reiterating why cleanliness is so important. While it is true that there are many factors that can influence the working life of a cutting fluid, such as dilution control, tramp oil, top up rates and so on, the key to ensuring maximum sump life from any fresh fill is machine cleanliness.
Why? During use machine tool fluid systems become contaminated with tramp oil, machining debris, hard water soaps and the likes that 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 significantly shorten the expected fluid life.
It is therefore essential that when any 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 the 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.
Failing to prepare is preparing to fail, and as with most jobs preparation is paramount when cleaning a machine tool. Prior to commencing this work, it is a good idea to ensure that waste containers have sufficient capacity to hold the spent fluid. The appropriate volume of Machine Tool System Cleaner must be available to ensure the job gets completed in a timely fashion. Obviously, there should be enough fresh fluid available to refill and subsequently top-up the system. Replacement filters should be available where required and the appropriate PPE equipment should be available and used as necessary.
ROCOL’s machine cleaning method follows a logical sequence that has been drawn together from years of experience gained in machine shops across the country. The first step is to introduce the appropriate machine tool cleaner, at the advised dilution ratio, into the old cutting fluid, ensuring the system is full so that the machine cleaner contacts every surface in the tank.
Ideally this mixture is allowed to circulate for 8 to 10 hours, but for a minimum of 4 hours. A good machine tool system cleaner allows the machine to remain in production during this cycle, so it should not impact on production capacity.
After the cleaner has had time to work switch off the power and remove tank covers and the swarf conveyor where possible, the interior of the machine is then brushed down to remove debris. The old fluid can then be removed 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.
The next step is to physically remove any solid debris from the tanks and conveyor. Remove and clean, or change, any filters and then rinse the system with clean water filling to the minimum level. The rinse water should be circulated for a few minutes and then pump out until dry before the swarf conveyor and tank covers are replaced.
The final step is to refill the tank with fresh cutting fluid and circulate immediately, catching the first few litres of the flow as this will be the last of the rinse water.
This method of cleaning a machine tool prior to any fresh sump fills to maximise the working life of the fresh coolant has been used in practise by ROCOL staff and customers for many years. It is a tried and tested formula. However, if you need any further help or advice please contact the ROCOL experts, as they will be happy to help.
