3 reasons why cutting fluid is inseparable from CNC machining

During CNC machining, we often see that the nozzle will spray a liquid on the cutting part, which is the cutting fluid. Cutting fluid has the functions of lubricating, cooling and cleaning, and plays a very important role in the automatic processing of CNC machine tools.

CNC machining


The cutting fluid can form an oil film on the surface of the workpiece and the tool, and can penetrate into the smallest gap of the workpiece to reduce metal-to-metal friction, which brings the following benefits:

(1) Reduce tool wear and prolong tool life.

(2) Reduce cutting resistance and process with less force.

(3) Prevent burrs from appearing on the edge and improve the precision of the machined surface.


The cutting fluid can reduce the heat generated during cutting, and the temperature of the workpiece during cutting can be as high as 600-1000 ℃, such as stainless steel, it is difficult to dissipate heat, and the workpiece will become hot. By reducing the temperature by cutting fluid, the following effects can be achieved:

(1) The thermal deformation of the tool is reduced, which prolongs the life of the tool.

(2) The machining accuracy is stabilized by reducing the thermal deformation of the workpiece and tools.

(3) High-speed machining is realized.

3. Clean

The jet cutting fluid can clean the chips generated during the cutting process, and the effect is as follows.

(1), to prevent damage to the workpiece due to chip adhesion.

(2), to prevent machining defects caused by chip clogging and accumulation.

(3), to prevent tool damage caused by chip entanglement.

Classification of cutting fluid

Cutting fluids can be divided into two types. Insoluble cutting fluids focus on lubrication (and some cooling) and can be used directly. Water-soluble cutting fluids are usually diluted with water and focus on cooling.

1.Insoluble cutting fluid

Insoluble cutting fluid is an oil-based cutting fluid with good lubricating effect, which can effectively prevent CNC machine tools and workpieces from rusting. It is mainly used for cutting operations that require high precision.

Insoluble cutting fluid can be divided into inert and active. Inert cutting fluid for gentle cutting and machining of mild steel. Active cutting fluid is used for difficult-to-cut materials and low-speed machining, such as gear cutting, which can effectively improve machining accuracy.

2.Water-soluble cutting fluid

Water-soluble cutting fluid is a cutting fluid that is mixed with water and oil. It has good cooling effect and is widely used in high-speed machining of machining centers.

There are three types of commonly used water-soluble cutting fluids

Emulsion, water-soluble cutting fluid composed of water, oil and surfactant, milky white liquid with large oily particles, highly versatile and widely used in machining centers.

Semi-synthetic water-soluble cutting fluid, composed of water, oil, surfactant and soluble substances, is a translucent liquid with small oil particles, with excellent cooling and penetration properties.

Fully synthetic water-soluble cutting fluid, composed of surfactant, amino alcohol and rust inhibitor. The oil particles are very small, the liquid is usually green in color, and has good cooling and durability properties.

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