The Lubricants for CNC Machining and Factors to Choose it Right.

When CNC machining a custom machined part, cutting heat will be generated
and there is friction between the work-piece and cutting tool. To improve the
CNC machining quality, it is necessary to choose the suitable lubricants for CNC machining to reduce the friction and dissipate the heat during the machining process.

In this article, we will discuss the types of lubricants for CNC machining, the advantage, and disadvantage of each lubricant, as well as the factors for
selecting the appopriate lubricant. 

lubricants for CNC machining

1. Types of lubricants for CNC machining

  • Water-based lubricant

This type of lubricant has high heat dissipation properties, which help to dissipate the cutting heat effectively and reduce friction. It is also easy to be cleaned and environmentally friendly.

However, it can cause rust and corrosion on the cutting tool due to the water base, thus, it is better to add a rust inhibitor if selecting a water-based lubricant, 

  • Soluble Oil

This lubricant is a mixture of oil and water, the special chemicals( emulsifiers) are added to form a mixture with water.

Soluble oil provides good lubrication as oil and good cooling performance as the water, also it is relatively cheap and will not catch fire due to the high water content.

However, because the soluble oil contains the oil component, it can be dirty and difficult to clean.

  • Dry Lubricants

During the CNC machining process, this type of lubricant can reduce the friction between the work-piece and cutting tool. 

The two main dry lubricants are graphite and molybdenum disulfide (MoS2). It
will not produce any mess or residue, because dry lubricants do not contain any liquid. 

However, it can cause dust to accumulate in the cutting area, also, it may not provide enough cooling performance.

  • Synthetic Lubricants

This lubricants do not contain a petroleum or mineral oil base, but combined alkaline organic and inorganic compounds. 

Synthetic lubricants provide excellent lubrication and cooling performance, leading to increase the cutting efficiency for high-speed machining processes, therefore, increasing productivity and reducing the machining cost. Also, the synthetic lubricants are resistant to oxidation and corrosion. 

However, it is relatively more expensive than the other lubricants.

2. How to Choose the Lubricant for CNC Machining Process? 

Lubricant is widely used in the CNC machining process, it helps to dissipate the cutting heat, and reduce the wearing of the cutting tool, resulting to improve machining quality of the custom machined parts.

So, what are the factors to be considered when choosing the lubricant?

  • Considering the material

There is not one of the lubricants that can fit for machining all the materials.

you should choose the lubricant that fits the non-ferrous metals for machining
the aluminum parts, and select a lubricant that is suitable for high-temperature applications when machining the stainless steel parts.

  • Considering the Machining Processes

Concerning the general CNC machining process, a water-based lubricant can dissipate the cutting heat between the workpiece and cutting tools efficiently. However, it is not suitable for CNC machining with deep or high-speed cutting. While a dry lubricant is suitable for high-speed CNC machining, it can not provide sufficient cooling performance.

  • Taking the Lubricant Properties into consideration.

A good lubricant can provide excellent lubrication, good cooling performance, and withstand high temperatures. In addition, the lubricant is easy to be cleaned and removed after use.

  • Is it Good for the Environment and Health. 

Some of the lubricants contain hazardous chemicals, which are harmful to the environment and human health. It is important to choose lubricants that are safe for both the operators of CNC machines and the environment.

In general, the water-based lubricant is more environmentally friendly than the oil-based lubricant.

  • Taking into account the Lubricant Cost.

Most people are prone to select a cheaper lubricant to save costs, but they are
not aware that the long-term cost may be more expensive if using a cheaper and lower-quality lubricant.

This kind of poor-quality lubricant can not provide sufficient cooling performance, also it will increase the wear of cutting tools and lead to poor machining quality.

Therefore, we should choose a cost-effective lubricant that can provide the required performance for a specific machining process, not only focus on the cheap price.


There are many types of lubricants, and the suitable lubricants can prolong the
life of the cutting tool and ensure good machining quality. By considering the 5 factors listed above, you may be able to find a cost-effective lubricant for your
CNC machining needs.