Introduction to Coolant

A coolant is a substance, typically liquidor gas, that is used to reduce or regulate the temperature of a system. Anideal coolanthas high thermal capacity, low viscosity, is low-cost, non-toxic,   chemically inert and neither causes nor promotes corrosion of the coolingsystem. The term also covers cutting fluids.   Industrial cutting fluid hasbroadly been classified as water-soluble coolant and neat oil cutting fluid. Water- soluble coolant is oil   in water emulsion. It has varying oil content fromnil oil (synthetic coolant).                   

Function of Coolant

1. Lubricating

The lubrication is where the coolantpenetrates into the contact area between grinding wheel and workpiece to form alubrication layer to reduce the interface friction.   This reduces the grinding force and abrasivewear as to extend the tool life of grinding wheel. The oil-based coolant hassuperior lubrication performance than the water-based coolant. Some additivesare frequently added to the coolant to improve the lubrication performance ofthe coolant.

2. Cooling

The coolant has cooling effect for bothworkpiece and grinding wheel.   Forworkpiece, the coolant absorbs heat, which protects the geometric accuracy andsurface quality of workpiece; For grinding wheel, the coolant can immediatelyand rapidly cool abrasive grains with high temperature. This thermal shockeffect can promotes the self-sharpening of the abrasive grains. Coolingfunction is associated with thermal conductivity, specific heat andvaporization heat of the coolant.

3. Cleaning

The coolant remove the chips and brokenabrasive grains from gap between grinding wheel and workpiece, or the porousstructure of grinding wheel, as to avoid affecting the processing accuracy andmaintenance of the machine. This cleaning performance is related to thepermeability, fluidity and pumping pressure of coolant. The permeability isassociated with the surfactant contained in coolant, while the fluidity iscorrelated to the viscosity of coolant. Coolant with good permeability and lowviscosity has good cleaning performance. In addition, it is suggested topumping coolant at a large flow rate and with high pressure to improve itsremoving ability of chips and abrasive grains.

4. Rust Protection

Because the new surface after grinding hashigh energy, it is very easy to react with oxygen and other substances in theair, resulting in the oxidation of workpiece. The coolant form a protectionlayer on the ground surface of the workpiece as to prevent workpiece fromcontaminations or oxidation.