Metalworking fluids – otherwise known as machining coolant, are used when machining or shaping metals to provide lubrication and cooling. Improving production efficiency isn’t just about investing in the latest machining technology. Manufacturers can find significant cost savings by making relatively minor changes, such as adopting a more cost-effective coolant management regime.

The maintenance, disposal, and recycling of metalworking fluids (machine coolants) should be a top priority for any machine shop concerned about cost and productivity.

Metalworking fluids and coolants have a cost. There is the initial cost of purchase, and then there are the labor costs and machine downtime costs that come with maintaining the machine coolant sump. Any manufacturer would agree, what coolant sump maintenance means is chips and slurry all over the shop-floor. Simultaneously, the tank is periodically emptied and cleaned, followed by mixing, lugging, and pouring heavy buckets filled with coolant.

Then come the frequent top-ups with more mess and hassle as fluid levels slowly fall. Six months to a year later, the operator spends time cleaning the settled dirt in the machine’s bottom and carry it away; and the cycle begins again.

Fluid management is time-consuming maintenance work, and it can be wasteful. The good news is there are ways to mitigate this waste while maximizing coolant effectiveness.

Metalworking fluid selection

Selecting a high-quality coolant that lasts longer is the first step of the puzzle. Also, it is advisable to limit the number of different coolants you use in your shop. Buying coolant in bulk helps reduce costs. It is vital to make sure that your parts cleaning systems are compatible with the selected coolant. It is almost an industry practice to select coolant based on price; however, it is essential to have a deep technical discussion with the metalworking fluid supplier regarding the type of process, the component’s material, etc. For example, aerospace giants like Boeing and Airbus have a very detailed and lengthy approval process for selecting their metalworking fluids. The aerospace companies give approvals for particular applications, and they expect documentation for any deviation in the manufacturing process. Only with such detailed approaches can one expect to have absolute control over manufacturing tolerances and accuracies.

Cleaning metalworking fluids (coolant)

Reducing coolant use is essential, but a second and equally important aspect of metalworking fluid maintenance is cleanliness. Tramp oil and other contaminants continuously bombard the water-soluble and synthetic coolants, making them tricky to maintain. You can extend the life of your coolant by at least 300% with good coolant management practices. Keeping coolant clean is easier and more cost-effective than having to replace it.

A coalescer oil-water separator or tube skimmer will remove tramp oil and dirt that collects in all machine tool sumps for almost the exact cost as a barrel of coolant oil. The coalescer will further discourage the anaerobic bacterial growth that feeds on whatever tramp oil is left. Effective tramp oil removal will avoid the need for biocides and maintain a proper pH level (always check with your cutting fluid supplier for maintenance recommendations).

See how a coalescer oil-water separator works –

Coolant health monitoring procedure

It is advisable to monitor the health of the metalworking fluid weekly. The shop in-charge needs to chalk out a detailed operating procedure to monitor the coolant’s health. Manufacturers should observe the following parameters to decide the health of the coolant-

  1. Hardness
  2. Chloride levels
  3. pH
  4. Concentration
  5. Bacterial growth

You will have to send coolant samples to labs to check the hardness, chloride levels, and bacterial growth. Electronic sensors are available to measure the pH, and you can use refractometers to check the concentration levels.

There are costs involved in monitoring the above parameters; however, it is worth it since it is expensive to change the coolant altogether. Watching the above parameters will give early signals of coolant going bad, positively impacting cutting tool life, machine productivity, and operator morale. Nobody likes to work with a constant coolant stink.

Automating coolant making process

Is your still manually mixing coolant? Bad idea. Automating the coolant preparation process will save your team valuable time and keep the coolant-water mixture optimum and consistent. Automating the process will eliminate the need for measuring cups and guesswork when preparing new or added amounts of coolant. What’s more, these mixing devices produce the correct droplet size and disperse those droplets evenly throughout the metalworking fluid. Set the dial to the desired concentration and turn on the water tap.

When it is time to change the sump, add some cleaner to the tank a day or two before. Adding a cleaner will help loosen the sludge that collects along the sides and bottom of the tank and the sticky stuff on the machine tool’s interior walls.

Regular machine sump cleaning

Machine sump cleaning involves much back-breaking manual labor. A coolant management device- A sump cleaner is an excellent investment. These machines make fluid maintenance as easy as vacuuming the dust off our house floor—wheel it over, plug it in and start sucking.

See how a sump cleaner works –

There are some machines which are all-in-one. The sump cleaner draws in the fines, sludge, and tramp oil from one end. The clean and machine-ready coolant emerges from the other. Each has pros and cons, but there’s no mess in either case, and it’s easy enough that sump cleaning is no longer something to be avoided. The result is that high-quality metalworking fluid is available all the time, with little to no waste.

Manufacturers looking to strengthen their bottom lines have to explore ways to get the most service out of metalworking fluids. How effectively a manufacturer manages coolant can impact profit margins, especially during challenging market conditions, such as when material costs are high, interest rates are rising, or there’s a recession. Companies that maximize coolant life position themselves for more profitable operations over the long run.

We hope you enjoyed reading this blog. Please do check out our other blogs and let us know your suggestions if any.

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