Mystery of cutting fluid foam: in-depth analysis of causes and countermeasures
In the field of metal processing, cutting fluid as an indispensable auxiliary material, its performance is directly related to the processing efficiency, tool life and workpiece quality. However, in practical applications, there are often a lot of foam on the surface of the cutting fluid, which not only affects the cooling and lubrication effect of the cutting fluid, but also may adversely affect the machine tool and the surrounding environment. In this paper, the causes of cutting fluid foam are discussed from four aspects: too low cutting fluid level, too fast flow rate, water tank design defect and too high surfactant content, and the corresponding solutions are put forward.
First, the cutting liquid level is too low: the hidden push hand of foam generation
The cutting fluid level is too low, which is an often overlooked factor that causes foam problems. When the liquid level drops to a certain extent, the contact area between the air and the cutting fluid increases significantly, which provides favorable conditions for the formation of bubbles. Especially in the high-speed cutting process, the friction between the tool and the workpiece generates a lot of heat, which promotes the rapid evaporation of the cutting fluid, further aggravates the interaction between the air and the liquid, and makes the tiny bubbles rapidly gather and rise. If the liquid surface is no longer sufficient to support the effective overflow of these bubbles, they will accumulate at the liquid surface to form a visible foam layer.
Solution strategy: Check and adjust the cutting liquid level regularly: ensure that the liquid level is always kept within the specified range, which can effectively cover the processing area and provide enough space for the smooth overflow of bubbles. Install automatic refill system: For large or highly automated machine tools, consider installing automatic refill device to monitor and replenish cutting fluid in real time to avoid foam problems caused by liquid level drop.
Second, the flow rate is too fast: the accelerator of bubble accumulation
The flow rate of cutting fluid in circulation system is one of the important factors affecting foam formation. When the cutting fluid flows through the pipe, nozzle and other parts at too fast a speed, it will produce a strong turbulence effect, which will not only increase the amount of bubbles produced, but also hinder the effective separation and overflow of bubbles. Especially at the nozzle, if the flow rate is too fast and the injection Angle is improper, the cutting fluid will directly impact the workpiece or the tool surface, producing a large number of tiny bubbles, which are difficult to escape in the high-speed flow of liquid, and eventually converge into the foam layer.
Solution strategy: Optimize the cutting fluid circulation system: rationally design the pipeline layout, reduce the fluid resistance, and control the flow rate of cutting fluid within a reasonable range. Adjust the nozzle Angle and flow rate: ensure that the nozzle Angle is moderate to avoid direct impact on the workpiece surface; At the same time, the nozzle flow is adjusted according to the processing requirements to reduce unnecessary turbulence.
Third, sink design defects: foam breeding hotbed
As a key component of cutting fluid storage and circulation, the design rationality of water tank is directly related to the control effect of foam. If there is too much right Angle or acute Angle design in the tank, these parts are easy to form vortex areas, increasing the retention and accumulation of bubbles. In addition, the nozzle position is set improperly, such as spraying directly at the wall of the sink, which will also cause the cutting fluid to produce a large number of bubbles after impact.
Solution strategy: Optimize the design of the sink: streamline the design, reduce the right Angle and acute Angle, reduce the generation of vortex zone; At the same time, the nozzle position is rationally arranged to ensure that the cutting fluid can flow evenly and smoothly into the sink. Add a defoaming device: install a defoamer, filter and other devices in the sink or circulation system to effectively remove the bubbles in the cutting fluid and prevent the formation and accumulation of bubbles.
High surfactant content: the internal driving force of foam generation
Cutting fluid usually contains a certain amount of surfactants to enhance its wetting, penetration and cleaning capabilities. However, when the surfactant content is too high, they can significantly reduce the surface tension of the cutting fluid, making it easier for bubbles to form and harder to burst. In addition, some types of surfactants also have good foaming properties, further exacerbating the foam problem.
Solution strategy: Reasonable control of surfactant content: According to the specific formula and processing needs of cutting fluid, precise control of the amount of surfactant added to avoid excessive use. Select low-bubble cutting fluid: When conditions permit, give priority to low-bubble cutting fluid or anti-foam additive cutting fluid to fundamentally reduce the risk of foam generation.
Conclusion
Although the problem of cutting fluid foam seems small, it has a non-negligible impact on the processing process and product quality. Through in-depth analysis of the root causes of foam generation, and adopt targeted solutions, we can effectively control the formation and accumulation of foam, ensure that the cutting fluid always maintains good cooling, lubrication and cleaning performance, and provide a strong guarantee for the efficient and stable operation of the metal processing industry. In the future, with the continuous progress of material science, fluid dynamics and automation technology, we have reason to believe that the problem of cutting fluid foam will be more comprehensive and thorough.
