Water-soluble metal working coolants, containing soluble oils, semi-synthetics and true synthetics. Used in many industrial applications such as drilling, milling, threading and reaming.
- mineral emulsifying oils (also known as milk oils, macroemulsions, high oil emulsions)
- semi-synthetic oils (semi-synthetic oils, micro-emulsions, semi-synthetic emulsions)
- synthetic liquids (chemical solutions)
Macroemulsions are characterised by a high mineral oil content of 50 to 85% by weight in the concentrate, which in addition consists of water, emulsifiers, detergents and other additives that give the emulsion the right performance properties and extend its service life. These are mainly corrosion inhibitors, EP additives, anti-foaming additives, bactericides and fungicides. Mineral emulsifying oils give good lubrication and have better cooling properties than non-emulsifying oils. The most common disadvantage of this type of emulsion is its inferior cleaning properties – the surfaces of the machine tool and workpieces can be covered with an oily layer and other deposits that are difficult to remove. In addition, they can ‘smoke’ because they do not cool as well as semi-synthetic and synthetic fluids. If improperly cared for, they can have poor stability or a short lifespan, as well as poorer protection of workpieces and machine parts from corrosion.
Semi-synthetic oils with a low to medium mineral oil content in the concentrate – from a few to 50 per cent – contain quite a few components that are also found in high-oil emulsions, but have more complex emulsifiers, i.e. components responsible for emulsion formation. Their properties can be described as intermediate between high-oil emulsions and synthetic solutions. They provide good lubrication, effectively reduce temperature, protect well against corrosion, have a longer service life and better cleaning properties than high-oil emulsions.
Synthetic fluids do not contain mineral oils. They contain detergent-like ingredients for better wetting and other additives to improve properties. They can be soluble or dispersible in water. Synthetic fluids generally work the cleanest compared to other types of machining fluids. In addition, they cool best, usually have good anti-corrosion properties and the longest service life. As a rule, they are transparent, allowing the operator to observe the machining process. They show a high degree of insensitivity to poor quality water.
