Cutting Fluids: Functions, Properties

Various functions of cutting fluids are

1. Cutting fluid cools the workpiece and tool by carrying away the heat generated during machining.
2. It acts as a lubricant at the friction zones, thereby increasing tool life.
3. As friction gets reduced, the forces and electricity power consumption decrease.
4. Using cutting fluids produces a better surface finish on the workpiece.
5. It causes the chips to break into small pieces.
6. It washes away the chips from the tool.
7. It prevents the corrosion of chips and machines.
8. Improves dimensional accuracy and control on the workpiece.
9. It permits maximum cutting speed, hence the time for machining reduces and the cost of manufacturing increases.

Properties to be possessed by the cutting fluids are

1. Cutting fluids should have low viscosity to permit the free flow of the liquid.
2. It should possess good lubricating properties.
3. It should have high specific heat, high heat conductivity and high heat transfer coefficient.
4. It should be non-corrosive to work with and machine.
5. It should be non-toxic to the operating person.
6. It should be odourless.
7. It should be stable in use and storage.
8. It should be safe.
9. It should permit a clear view of the work operation.

Most commonly used cutting fluids are

1. Cast Iron: No cutting fluids are used.
2. Steels: Lord oil is used with mineral oil.
3. Alloy steel: Sulphur brass oil with mineral oil is used.
4. Copper: A soluble oil with 90 to 95% water content is used.
5. Aluminium: Mineral oil with soluble oil cutting fluids are used as cutting fluids.