The best referee to intervene in the chemical showdown between coolant and chips is filtration. This summary will outline applications in order of simplest to the most aggressive. Large and heavy chips, like apples from a tree, will fall to the ground, or bottom of the tank. As they accumulate, they nominally chemically interact with coolant but also form safe harbors for bacteria and reduce the tank’s fluid capacity. This is easily handled automatically by chip conveyors and augers…easily handled manually by vacuum systems and shovels.
Lighter or smaller chips tend to stay buoyant in the fluid pool. Depending upon the weight of the material, they may circulate with the fluid for some time before nestling with larger chips. While swimming in the coolant, chemically reactive metals will begin to reduce its strength. These are easily captured by bag or cartridge filtration methods, paper bed filters, and if magnetic, magnetic separators. Some may pose danger to submersed pumps, depending upon their size, shape, and quantity.
The tinier chips–those that are near the size (1-50µ) of our champions, the coolant molecules–are ready to take them down. Least damaging materials stay suspended in the fluid and easily circulate within the coolant pool, streaming back to the tool and workpiece to cause worn tooling and poor surface finishes. Staged particle filtration methods are recommended here, reducing filter cleaning or replacement. This kind of particle filtration method offers multiple stages, filtering large size particles such as 100µ first, then 50µ, then 5µ, etc.
The high-strung, most chemically-reactive chips may form grease or sludge (swarf). If the formation sinks, they are best handled by manual filtration methods as given their new solidity, they tend to plug other filtration methods. If they float, they are best captured by coalescers, and readily drained to waste. For cyclone filtration, such as a centrifuge, it is best to check with the coolant manufacturer for recommendations as to their use per application. These systems easily remove solids from fluid, however they may also separate coolant base from the fluid pool.