Image of Tips to Selecting Your Perfect CNC Coolant

Tips to Selecting Your Perfect CNC Coolant

Selecting your perfect CNC coolant can be an arduous process, as many users know. When you are at the beginning stages in the process, it is best to ask the manufacturer or their representative as many questions as possible so you don’t waste your time or money.

Choosing a coolant for a CNC machine depends on several factors:

Machine Material

Choose a coolant compatible with the machine’s material to prevent corrosion. Coolant is used to prevent corrosion in CNC machines because:

  • High temperatures generated during cutting operations can cause metal components to become oxidized, leading to corrosion.
    Coolants help to dissipate heat and reduce temperatures, reducing the risk of oxidation and corrosion.
  • Coolants also help to flush away metal chips and other debris generated during the cutting process. These can be abrasive and contribute to corrosion if left in contact with metal surfaces.
  • Certain types of coolants contain corrosion inhibitors, which form a protective layer on metal surfaces to prevent corrosion.

Overall, the use of coolant helps to extend the life of CNC machine components. This is done by reducing the risk of corrosion, as well as improving the quality of cuts which helps increase productivity by promoting efficient cooling.

Cutting Process

Select a coolant suitable for the type of cutting process being employed, such as turning, drilling, or grinding. Different types of cutting processes require coolant for various reasons:

  • Turning: Coolant is needed to reduce heat generated by friction between the cutting tool and the workpiece.
  • Drilling: Coolant is used to lubricate the drill bit, remove chips and to keep the drill bit cool to prolong its life.
  • Grinding: Coolant helps to keep the grinding wheel and workpiece cool, reduce heat generated by friction, and wash away grinding debris.
  • Milling: Coolant helps to lubricate the cutting tool, reduce heat, and flush away chips to keep the cutting surface free of debris.

In general, coolants are used in the cutting processes to improve cutting performance, extend tool life, and prevent surface damage to the workpiece. The specific requirements of each cutting process determine the type and properties of coolant required for production efficiencies.

Cooling Requirements

Consider the cooling requirements of the specific cutting operation. This can include desired flow rate and cooling effectiveness. Pay attention to cooling requirements because of the:

  • Tool life: Effective cooling helps prolong tool life by reducing the tool’s temperature and preventing thermal damage.
  • Surface finish: Adequate cooling can improve surface finish by preventing the formation of heat-affected zones and reducing residual stress.
  • Cutting speed: Proper cooling can increase cutting speed by reducing the temperature generated during cutting, allowing for higher cutting speeds.
  • Workpiece quality: Effective cooling can improve workpiece quality by reducing the formation of cracks, warping, and other deformations.
  • Machine reliability: Proper cooling can enhance machine reliability by reducing the risk of component failure due to overheating.

Choosing the right coolant and cooling system can improve cutting efficiency and workpiece quality, while extending the life of tools and machines.

Health and Safety

Choosing a coolant with low toxicity and volatility is important for health and safety reasons. Coolants can be hazardous if ingested, inhaled or contacted with the skin. Low toxicity reduces the risk of exposure to toxic substances. Volatility refers to the tendency of a substance to evaporate. Low volatility reduces the risk of explosion or fire in the workplace. Additionally, coolants with low toxicity and volatility are less likely to harm the environment. This is important for sustainability and compliance with state, local and federal regulations.


Cost is an important factor to consider when choosing a coolant for a CNC machine. It can have a significant impact on the overall cost of your operation. The initial cost of the coolant, as well as the cost of ongoing maintenance and disposal all add up over time and affect the bottom line. It is important to consider the cost of the coolant when making a decision.  You obviously want to minimize costs and maintain a budget for the operation of the CNC machine.

Environmental Impact

Select a coolant with a minimal environmental impact, such as a biodegradable or low-toxicity coolant. This helps to minimize the negative effects of coolant discharge on the environment. Conventional coolants can contain hazardous chemicals that can harm the environment if not properly disposed of. They can also contribute to air and water pollution. By choosing a coolant with a minimal environmental impact, such as a biodegradable or low-toxicity coolant, it helps to reduce the amount of waste that needs to be disposed of and the risk of environmental contamination. This can also help to reduce the environmental impact of the manufacturing process. Which in turn contribute to a more sustainable and eco-friendly workplace.

Other coolant performance criteria that should be considered are:

Stable in Solution

Choosing a stabilizing agent for a coolant helps to maintain its properties over time. This ensures its effectiveness in the cooling process. Stabilizing agents help to prevent bacterial growth and contamination. Bacteria can reduce the cooling efficiency and cause corrosion or deposits on your machine parts. It also helps maintain the pH balance of the coolant. You want it to remain within a neutral range that is suitable for the machine and cutting process. Another reason is that it will prevent the separation of components in the coolant mixture, maintaining its consistency and effectiveness. Finally, it will help inhibit the formation of rust and corrosion, protecting the machine and cutting tools.

Using a stabilizing agent can improve the performance and longevity of the coolant, and help to ensure a safe and efficient cutting process.

Controls Foam and Mist

Controlling foam and mist is important in a CNC machine because:

  • Improved visibility: Excessive foam and mist can obstruct the operator’s view, reducing visibility and potentially leading to mistakes during the cutting process.
  • Machine protection: Foam and mist can cause damage to the machine, such as clogging coolant delivery systems, rusting and corroding metal surfaces, or creating a fire hazard.
  • Operator safety: Excessive mist can present an inhalation hazard to the operator, potentially leading to respiratory problems.
  • Increased efficiency: A well-controlled coolant system helps maintain optimal cutting conditions, improving the efficiency of the machine and reducing the need for frequent stops to clear foam or mist.

Choosing a coolant that is specifically designed to control foam and mist can help prevent these issues and maintain safe and efficient operation of the CNC machine.

Controls Undesirable Odors

Coolants can produce undesirable odors due to bacteria growth and chemical reactions. Choosing a coolant with low bacterial growth and chemical reaction potential can help to control these odors. Additionally, some coolants contain biocides or other odor control agents to help mitigate the production of unpleasant smells. It is important to consider this factor when selecting a coolant, especially in environments where workers may be exposed to the coolant for long periods of time.

Forms No Undesirable Residues

It is important to choose a coolant that forms no undesirable residues in a CNC machine to ensure the following:

  • Machine performance: Residues can clog coolant passages, reducing cooling effectiveness and potentially leading to machine damage.
  • Product quality: Residues can negatively impact the surface quality of machined parts.
  • Health and safety: Certain residues can be toxic or flammable, creating a health and safety hazard in the workplace.
  • Maintenance: Residues can require frequent cleaning, increasing maintenance time and costs.

Therefore, selecting a coolant that forms no undesirable residues helps ensure smooth machine operation, high product quality, and a safe and efficient work environment.

Long fluid life, given proper maintenance

Choosing the right coolant for your CNC machine is important to prolong fluid life for several reasons:

  • Compatibility: Selecting a coolant that is compatible with the machine material and cutting process prevents chemical reactions that can cause breakdown and degradation of the coolant.
  • Longevity: Proper coolant selection can extend the life of the fluid by preventing contamination, oxidation, and bacterial growth, which can lead to degradation.
    Maintenance: A well-chosen coolant can reduce the frequency of maintenance required, such as topping off the fluid levels, cleaning the system, and filtering.
  • Performance: The right coolant can improve performance by providing the necessary lubrication and cooling to the cutting operation, which can lead to better cutting accuracy, surface finish, and increased tool life.
  • Cost savings: By extending the life of the fluid and reducing the frequency of maintenance, a well-chosen coolant can lead to cost savings in the long run.

Safe to Workers

It is important to choose a coolant that is safe for workers because some coolants can be hazardous to human health if not handled correctly. Inhaling coolant mist or having skin contact with coolant can cause respiratory problems or skin irritation, respectively. Coolants that contain hazardous chemicals or are flammable can also pose fire and explosion risks. To protect workers’ health and safety, it is important to choose a coolant that is low in toxicity, volatility, and flammability, and one that meets local health and safety regulations.

Safe and Easy to Dispose

Choosing a coolant that is easy to dispose is important because it minimizes the environmental impact and potential health hazards associated with coolant disposal. Coolants often contain chemicals that are toxic and/or flammable. This can be harmful to the environment and to people if not disposed of properly. A coolant that is biodegradable or low-toxicity is easier to dispose of. And it also reduces the risk of environmental contamination or harm to human health. Additionally, choosing a coolant that is easy to dispose of may also reduce disposal costs and comply with local regulations regarding coolant disposal.

Overall, coolant, no matter its quality or cost, will fail at some point. That point can be much sooner than expected if the coolant is not properly maintained. However, if taken care of properly, its longevity will increase and it will perform as it was intended.

Preventing your coolant from failing is critical to plant operations and budget. There are so many nuances to coolant. Some are chemical, some are biological, some are mechanical.

Each, however, is just as important as the other because they all have a hand in affecting its overall performance. This affects your machines, your tools, your parts, your workers, and your bottom line.

Need help in managing your fluid? Check out some of our solutions for metalworking fluid management.



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