Coolants containing both oil and water require surfactants to form and maintain emulsions, a mixture of the oil and water, so that both properties can work together. Considerations for Choosing a Coolant Different metal working processes have varying cooling and lubrication needs. Coolants have many properties that increase their efficiency, extend their life, and minimize the potential to damage tools and products. Therefore, when choosing a coolant, many factors need to be considered. The effectiveness of a coolant for heat transfer and as a lubricant decreases for a number of reasons.
Coolants break down in process.
These substances prevent the coolant from working. Selective depletion of a fluid component could also reduce coolant effectiveness. For example, swarf is particulate metal created during the grinding or cutting of metals. The presence of swarf creates friction, defeating both the lubricating ability and cooling capabilities of the coolant. The increased concentration of tramp oil similarly interferes.