Coolant / Metalworking Fluid Types
Coolant is catagorized into four main groups, and each group is available in many different formulations. The following are the coolant catagories and the amount of oil present in their formulation:
||Contains 60-85% mineral oil and emulsifies into water
||Contains 5-50% mineral oil and emulsifies into water
||Contains no mineral oil
||Contains 70-85% mineral oil and is not water-miscible
A soluble oil based coolant works relatively well over a broad range of operations, but has lower tramp oil rejection properties then that of a semi-synthetic. A full synthetic has great tramp oil rejection properties but can lead to rust on machine interiors. Straight oils are primarily used in drilling and tapping operations, but are the most stable and easiest to maintain overall since they contain no water.
You will want to choose a coolant with the best overall performance rating for all your applications, if and whenever possible. For our purposes here, we will focus on those that will be mixed with water, since these are the ones that require the most maintenance to keep alive and well.