What is the liquid used in CNC machining? Why use it?

What is the liquid used in CNC machining? Why use it?

Content Catalog

In the process of CNC machining, you may have seen such a scene: the tool is cutting the part, and there is a nozzle next to the tool, which continuously sprays out a liquid similar to oil/water.

This fluid is cutting fluid.

It is an industrial liquid used in metal cutting and grinding processes to cool and lubricate cutting tools and workpieces. The cutting fluid is made of a variety of super functional additives through scientific compounding. Performance, lubricating performance, anti-rust performance, degreasing and cleaning function, anti-corrosion function, easy to dilute. It plays a very important role in the automatic processing of CNC machine tools.

We’ll take you a step further in this article!

The role of cutting fluid


Cutting fluid can form an oil film on the surface of workpieces and tools, and can penetrate into the smallest metal gaps and irregularities, reducing friction between metals. This has the following effects:
① Reduce tool wear and prolong tool life.
② Reduce the cutting resistance, and can process with less power.
③ Prevent burrs on the edge and improve the precision of the processed surface.

cool down

Cutting fluid can reduce the heat generated during cutting operations, and its temperature can be as high as 600-1000°C. Especially for workpieces with low thermal conductivity like stainless steel, the heat is difficult to dissipate, and the workpiece will become hot.
Using cutting fluid to lower the temperature can bring the following effects:
① Reduce the thermal deformation of the tool and prolong the tool life.
② The machining accuracy is stabilized by preventing thermal deformation of the workpiece and tool.
③ Realized high-speed machining.


Spraying cutting fluid can wash away the chips generated during the cutting process and play a role in cleaning the workpiece, which can bring the following effects:
① Prevent scratches on the workpiece caused by chip adhesion.
② Prevent processing defects caused by clogging and accumulation of chips.
③ Prevent tool damage due to chip entanglement.


Cutting fluid also has a certain anti-rust ability. It can prevent corrosive substances such as sludge and other liquids used in environmental media and processing procedures from corroding metals.

Classification of cutting fluid

Cutting fluid can be roughly divided into two types: insoluble and water-soluble. Insoluble cutting fluid can be used directly, focusing on lubrication (and a small part focusing on cooling). Water-soluble cutting fluid is usually used after diluting with water, focusing on cooling.

insoluble cutting fluid

Insoluble cutting fluid is a cutting oil with oil as the main component. It has a good “lubricating” effect and can effectively prevent rusting of CNC machine tools and workpieces. It is mainly used for cutting operations that require high precision.
Insoluble cutting fluid can be divided into inert type and active type. The inert type is used for light cutting and processing of soft metals, which can effectively improve tool life. The active type is used for difficult-to-machine materials and low-speed processing, such as gear cutting, which can effectively improve the processing accuracy.

water soluble cutting fluid

Water-soluble cutting fluid is a kind of cutting oil mixed with water and oil, which has a good cooling effect and is widely used in high-speed machining of machining centers.
There are three types of water-soluble cutting fluids commonly used: emulsion, soluble, and dissolving fluid.
Emulsion, a water-soluble cutting fluid made of water, oil, and surfactants, is a milky liquid with large oily particles. It has high versatility and is widely used in machining centers.
Soluble, a water-soluble cutting oil made from water, oil, surfactants, and soluble substances, is a translucent liquid with small oil particles. Has excellent cooling and penetrating properties.
Dissolving fluid, a water-soluble cutting oil made of water and soluble substances. The oil particles are very small and the liquid is usually green in color with excellent cooling and durability.

The above is an introduction to the function and classification of cutting fluid, I hope it can help you!

Related Posts
Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

  • Quick Quote

    Our professional team will reply you promptly and accurately.

    Want to source from China? Remember to avoid these 7 mistakes!

    China has always been popular with global buyers due to its high cost-effective procurement. This is…