Types of coolant

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This article delves into the various types of coolants used in CNC machines, focusing on their unique properties and applications. It explores key categories such as water-soluble coolants, synthetic solutions, and mineral oil-based options, highlighting their benefits and potential drawbacks. By understanding these differences, you can make informed decisions on the best coolants for cnc machines, its tasks and materials.

To date, about 90% of metalworking equipment uses coolant for cooling and lubrication. The remaining 10% can be attributed to dry processing incl. cooling with compressed air.

Types of Coolant

There are 2 main types of coolant oil used in CNC machine:

1. Insoluble cutting, grinding, forming and other oils
   Pure mineral or ester (vegetable) oils which do not dissolve with water and are used in operations with priority for lubrication, for example during gear processing, machining on swiss type lathes, in broaching operations or special application like dielectric fluid for EDM processing.
2. Water-soluble coolants
   On modern CNC machines, in most cases, water-soluble liquids are used, which form an emulsion by mixing with water. The concentrate of such coolants consists of a base which can be mineral or ester oil, water (for synthetic) or polymers. To obtain a stable emulsion, emulsifiers are used. Plus, various additives are added to protect against corrosion, increase lubricity and ensure long-term lifetime. Water-soluble coolants are usually used in dissolved form at a concentration of 3 to 15%.

In turn, water-soluble coolants can be divided into their 4 main categories:

A. Coolant based on mineral oils

They contain 50–80% of the mineral oils.

Pros:

• High lubricity
• Cost (are the least expensive choice)

Cons:

• Low stability, incl. tendency to bacterial contamination
• Low cooling capacity
• Low flushability (high flow away rate)
• Poor compatibility with some materials, incl. aluminum (darkening)
• Dirty Work Area

CNCmarket.ca does not supply pure mineral oil coolants.

B. Synthetic coolants

They do not contain mineral oils. You may be surprised but the base for classic synthetic coolants used in CNC machines is water.

Pros:

• High cooling capacity
• Good washability
• Resistance to bacterial contamination

Cons:

• Low lubricity
• Low corrosion protection
• Sensitivity to concentration
• Poor compatibility with certain materials, incl. aluminum (darkening and inability to perform some operations, such as small threads cutting and processing aluminum at higher speeds)

EASYCUT range of fully synthetic coolants consist of SYN311

C. Semi-synthetic coolants

They contain 5–49% of the mineral oils

Pros:

• High cooling capacity
• Good lubricity
• Good corrosion protection
• Resistance to bacterial contamination
• High Stability
• Good washability (optimal flow rate)
• Material versatility
• The best price for value rate

As you can see with the right selection of the best CNC machine coolant and good maintenance, semi-synthetic coolants have the greatest number of advantages. EASYCUT range of semi-synthetic coolants consist universal UNI301 , aluminum targeted PRO301 , heavy duty BVR451 and basic BASE201 for light duty machining incl. grinding.

D. Coolant based on vegetarian (ester) oils

They contain 5–49% of the ester oils

Pros:

• Environment safety
• High cooling capacity
• Great lubricity
• Good corrosion protection
• Resistance to bacterial contamination
• Even Higher Stability
• Good washability (optimal flow rate)
• Material versatility
• No residues on the parts

Cons:

• High cost

The best environment friendly coolant type if it fits to your budget. Please check EASYCUT VEG001 for details.

E. High Tech Synthetic coolants based on polymer

They do not contain mineral oils. The base is polymer (glycol).

Pros:

• High cooling capacity
• Good lubricity
• Good washability
• Resistance to bacterial contamination
• Good corrosion protection
• No residues on the parts
• High Stability
• Composite and plastic friendly

Cons:

• High cost

In case you need a heavy duty synthetic colorless and odorless coolant which will not left any residues on your part please check EASYCUT POLY601 . POLY 601 is NOT compatible with aluminum.

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