Cutting fluid plays a crucial role in the metal processing process. The factors causing foaming of the cutting fluid include various aspects such as the introduction of gases, liquid vibration, lubricant composition, temperature changes, liquid contamination, water quality issues, loose sealing of the fluid circulation pump, excessive cutting fluid flow rate, insufficient volume of the liquid tank, and unreasonable system design.

These foams not only affect the performance and effectiveness of the cutting fluid, reducing the cooling and lubrication effects, but also may increase the consumption of the cutting fluid and even cause problems such as the overflow of the cutting fluid.

I. Gas mixture 

During the use of the cutting fluid, it may be contaminated by air, hydraulic oil or other gases. These gases will form bubbles in the cutting fluid, causing the liquid to foam. 

II. Liquid Vibration 

When the cutting fluid is subjected to vibrations from the machine tool or the workpiece, it will undergo intense agitation, forming a large number of bubbles, and subsequently generating foam. 

III. Additive Issues 

Some surfactants or emulsifiers added to the cutting fluid, if used in excessive amounts or added improperly, can also cause the cutting fluid to form foam. 

IV. Temperature Changes 

During the use of the cutting fluid, due to the heat generated during the cutting process, the temperature of the liquid may rise. High temperature will accelerate the decrease in the solubility of gases, causing the gases to be released from the liquid and form foam. 

V. Operational Issues 

When using cutting fluid, if the operation is improper, such as injecting too quickly or with an incorrect injection angle, it can also cause the cutting fluid to form bubbles. 

VI. Liquid Pollution 

The cutting fluid may be contaminated by chips, grease, impurities and other substances, which could interfere with the surface tension of the liquid and cause it to form foam. 

VII. Sealing Issues of Fluid Circulation Pumps 

If the seal of the fluid circulation pump is not tight, it may also cause the liquid to form bubbles. 

VIII. Cutting Fluid Flow Rate and Liquid Tank Design 

If the flow rate of the cutting fluid is too fast, it may cause the bubbles not to have enough time to escape, resulting in the accumulation of foam in the cutting fluid. At the same time, problems such as a small volume of the liquid tank or too many right angles in the water tank design, as well as overly straight nozzle angles, may also increase the formation of foam.

The influence of cutting fluid foaming 

The foaming of cutting fluid will have the following series of adverse effects on the processing process: 

01 Reduce cutting quality 

The foam will interfere with the normal contact between the cutting fluid and the cutting area, preventing the cutting fluid from effectively cooling and lubricating the cutting tool and the workpiece. This will increase the friction between the cutting tool and the workpiece, thereby reducing the cutting efficiency and even causing tool wear and a decline in the surface quality of the workpiece. 

02 Increase in cutting fluid consumption 

The foam will occupy a portion of the space in the cutting fluid container, resulting in a reduction of the effective capacity of the cutting fluid. This means that the cutting fluid needs to be added or replaced more frequently, thereby increasing the consumption and cost of the cutting fluid. 

03 The performance of the machine tools has declined. 

Bubbles may enter the hydraulic and cooling systems of the machine tool, which will have a negative impact on the normal operation of the machine tool. Excessive bubbles may cause unstable hydraulic system pressure, failure of hydraulic components, and poor cooling effect of the cooling system, thereby affecting the machining accuracy and stability of the machine tool. 

04 Environmental Pollution and Resource Waste 

The foaming of the cutting fluid will cause it to spill over and contaminate the containers holding the cutting fluid as well as the ground. This not only damages the working environment but also leads to the waste of the cutting fluid. 

05 Impact on Product Performance 

Foaming of the cutting fluid will affect its lubrication and cooling effects, leading to unstable rust prevention performance, cleaning performance, and extreme pressure performance, thereby affecting the transmission of power and signals of the product. 

When using cutting fluid, it is necessary to control the generation of foam, ensuring the stable performance and smooth flow of the cutting fluid. This will enhance processing accuracy, guarantee processing quality, reduce tool wear and increase the service life of the tools.

The method for solving the problem of cutting fluid foaming 

01 Optimize the cutting fluid formula 

Choose emulsifiers with low foaming properties. The characteristic of these emulsifiers is that they are not prone to foaming, thereby reducing the generation of foam at the source. 

02 Control the concentration of the cutting fluid 

Ensure that the concentration of the cutting fluid meets the requirements, and avoid the formation of bubbles due to different concentrations. When adding additives, be sure to mix the cutting fluid evenly. 

03 Use defoamer 

Add an appropriate amount of defoamer to the cutting fluid. This helps reduce the bubbles in the cutting fluid and the bubbles produced during the production process. However, when using it, follow the instructions carefully to avoid overuse, as excessive use may have a negative impact on the performance of the cutting fluid. 

04 Adjust the usage method of cutting fluid 

Pay attention to the height of the cutting fluid nozzle and the speed of the fluid ejection. Avoid excessive speed which may cause bubble formation. Additionally, the liquid level of the cutting fluid should be maintained at an appropriate height. Regularly check and replenish the cutting fluid to ensure that the liquid level is not too low. 

05 Improving Circulation and Stirring 

For the foam caused by the introduction of gas, enhancing the circulation and stirring of the cutting fluid can help remove the gas and reduce the formation of foam. 

06 Control impurity content 

Reasonably control the impurity content of the cutting fluid to prevent its deterioration and thereby reduce the generation of foam. Regularly cleaning the processing equipment can effectively reduce the impurity content of the cutting fluid. 

07 Use Soft Water 

Adding an appropriate amount of soft water to the cutting fluid can reduce the content of hard water ions, which helps prevent the cutting fluid from oxidizing or deteriorating, thereby minimizing the formation of foam. 

To prevent the formation of bubbles in the cutting fluid, it is necessary to consider multiple aspects such as formula selection, usage method, and impurity control comprehensively. By implementing these measures, the occurrence of cutting fluid bubble formation can be effectively reduced, thereby improving processing efficiency and product quality.