Cutting Fluid: Definition, Types, Properties, Purpose, And Applications [PDF]

Cutting fluid is used in machining operations where heat is generated. This is helpful in smooth machining operations and increases tool life. Let us learn more about cutting fluids with types, properties, purpose, and applications in this article. At the end of this article, there will be a link to download a cutting fluid PDF copy for your future reference.

What is cutting fluid?

Cutting fluid is a liquid or solid substance used in the machining process to cool down the tool, lubricant machine parts, reduce wear and tear, aid in the smooth machining operation, and help is getting better quality parts.

cutting fluid
Image Credit : Wikipedia

Purpose Of Cutting Fluid

Cutting fluids do a different set of jobs during the machining process. Many of us may think that cutting fluid is used only for cooling purposes. But that is not true, and cutting fluids help machining operations in many ways. Let’s see what the use of cutting fluids is.

To cool The tool

During machining operations, a lot of heat is generated. Cutting fluid helps to reduce that heat and cools the tool: this increases tool life and smooth machining operations.

To lubricate moving parts

Cutting fluid is also used as a lubricant so that tools can move easily. Frankly speaking, not only tools but cutting fluid can be used anywhere in the machine where there are moving parts.

To reduce wear and tear

Since cutting fluid helps is the smooth movement of parts in a machine, there will be less wear and tear. This increases machine life and tool life.

To clean the tool and machine

Cutting fluid is also used for cleaning the tool and machine. Especially in areas where cleaning is tough, cutting fluid spray jets helps to clean those areas.

To improve surface texture and finished part quality

Since the cutting fluid is used as a lubricant, cleaner, and cooling medium, there are high chances that the surface texture of the finished part will have fewer foreign particles. This helps in gaining a smooth surface finish and improved parts quality.

To reduce energy consumption

Cutting fluids reduces wear and tear. This reduces the force required to move machine parts. When there is less force required, there will be less energy and power consumption.

Reduces corrosion

Since cutting fluids help moves away from all foreign particles, there are fewer chances of corrosion. Also, when cutting oils are uses in machine parts, it eliminates the corrosion by the chemical reaction.

To dissipate heat

Cutting fluids act as a medium to dissipate heat from the workstations. So your workstation and the machine can perform at the optimum level to give the best output.

Types Of Cutting Fluid

Below are a few types of cutting fluids used in industries. But the list is not exclusive and many industries may use special types of cutting fluid based on specific applications.

  • Water
  • Cutting oil
  • Mineral oil
  • Soluble oil or emulsions
  • Synthetic fluids
  • Semi-Synthetic fluids
  • Solid lubricants


Water has high specific heat but poor lubricant property. So water may dissipate heat properly but may not be good for lubricating parts. Applications like grinding use water as cutting fluid.

Cutting oil

Cutting oil is a blend of lubricant and coolant. It is basically composed of mineral oil and fatty oil. Machinery that is operated by hand uses cutting oil.

Mineral Oil

Mineral oil is a light mixture of higher alkalies from mineral sources, particularly a distillate of petroleum. Mineral oil is used in heavy-duty production machines. Mostly suitable for cutting steel.

Soluble oil or emulsions

Soluble oil is a mixture of petroleum oil ( more than 50%) and water. When petroleum oil mixes with water, it forms a milk-like substance. Soluble oil is often used with other emulsifiers ( sodium sultanate, fatty acid, etc.) and additives. This cutting fluid is used in production types of machinery having medium to high cutting rates.

Synthetic fluids

Synthetic fluids are water based fluids without oil. These are good for cooling but not lubrication.

Semi-Synthetic fluids

Semi-synthetic fluids have 5-20% of oil in order to ease in lubrication. So semi-synthetic fluids help in both cooling and lubrication.

Solid lubricants

Solid lubricants mean that the lubricant is in solid form when it is applied. Popular solid lubricants are soap bars, wax bars, etc.

Properties of cutting fluids

Here are few qualities that cutting fluids should have in order to have smooth machining operations

  • Should have lubricant properties
  • Should not corrode parts
  • Should be able to dissipate heat. Should have a high heat absorption rate
  • It should have a low viscosity so that cutting fluids can reach every corner.
  • Should have a high flash point so that it should not catch fire at high temperatures
  • Should not do any such chemical reactions with tools and machine parts that cause damages
  • Should have non-foaming capabilities.
  • It should be odorless and transparent so that it does not cause a problem to the operator.
  • Cutting fluid should be non-toxic and non-flammable
  • It should have a smaller molecule size for quick diffusion

Cutting fluid applications

  • Cutting fluids can be used as a coolant to cool the tool and machine parts
  • It can be used as lubricants for the smooth movement of tools and machine parts.
  • It can be used as both lubricants and coolants.
  • It can be used as a cleaning agent to remove all foreign particles and metal chips from the machine.

Selection of cutting fluid

Selection of cutting fluid depends on many factors as shown below.

  • Type of machining operation being performed
  • Type of tool that is going to be used.
  • The material of tool and machine components
  • The amount of heat gets generated.
  • Particle or chip size during machining operations
  • Presence of foreign particles.
MaterialMilling TurningDrillingThreadingReaming
AluminiumSoluble oil
Lard oil
Soluble oilSoluble oil
Soluble oil
Mineral Oil
Mineral Oil
Soluble oil
Mineral Oil
Mineral oil
Alloy SteelSoluble oil
Mineral oil
Soluble oilSoluble oil
Mineral oil
Soluble oil
Mineral oil
Soluble oil
Mineral oil
CopperDry Soluble oilSoluble oilSoluble oil
Mineral Oil
Soluble oil
Lard Oil
Soluble oil
Lard Oil
Cast IronDry Soluble oilDry Soluble oilDry Soluble oilDry Soluble oilDry Soluble oil
BrassDry Soluble oilSoluble oilDry Soluble oilSoluble oilDry Soluble oil
BronzeDry Soluble oilSoluble oilDry Soluble oilSoluble oil
Lard Oil
Dry Soluble oil
Mineral oil


Cutting fluid is a must for any cutting or machining operation. Without cutting fluids, no operation can be performed. If you are working on the shop floor, you should have a basic knowledge of cutting fluid to do your job better.

I tried to cover the basics of cutting fluid in this article. However, there is a lot to learn if you want to dig into this subject. However, if you have any questions on cutting fluids, you can always post your message under the comment section, and I will try to reply to the best of my knowledge.

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Frequently Asked Questions ( FAQ)

What is cutting fluid

A cutting fluid is a liquid or solid substance used to cool the tool or machine components, lubricate moving parts, clean foreign material, and dissipate heat away from the workstation.

What does cutting fluid do?

1. Cool the tool and machine parts
2. Lubricate the tool and machine parts
3. Clean the machine bed


A 2004 batch Mechanical Engineering graduate From NIT, Agartala. Close to 16 years of experience in the field of consumer electronics and appliances domain as a Sr. Design Engineer and Team Leader in India and the United States. A GD&T practitioner, with expertise in Lean Manufacturing and Six Sigma. Crazy about exploring CAD-CAM tools and in his free time love to go for a ride with his champ, Rian.