Coolant does more than its name implies. Beyond preventing cutting tool wear and heat removal from workpieces and tooling, the lubrication improves part quality and its flushing ability clears chips from the cutting zone. The result? Increased and enhanced throughput. 

Cutting fluid’s capabilities are critical in high-volume computer numerical control (CNC) metalworking operations — but even the industry’s best coolant can’t do its job without the right delivery system in place. 

Coolants are dispersed on workpieces in various ways, either as mist or vapor, via high-pressure jet, flooding, or even drop by drop. Not using the right method for your operation may result in damaged equipment or coolant overuse, driving up labor, supply, and fluid costs. 

How do machine shops know what system to use? Read on for the most common CNC coolant delivery methods and when it’s best to use them:


Flooding systems, which are the most common type of coolant delivery technique, unleash a cascade of coolant onto workpieces and cutting tools, providing maximum cooling, lubrication, and chip clearing ability. Because the flood volume and pressure actively wash chips away, this method of coolant delivery is incredibly effective. 

However, it’s important to note that it uses large amounts of fluid that needs to be managed properly. Selecting the correct coolant for your application, and paying extra attention to proper coolant management protocols is the only way to avoid wasting coolant and increasing operating costs. Most fluids in the TRIM® catalog are compatible with this type of equipment. 


  • Provides maximum lubrication and cooling to workpieces and cutting tools.
  • Maximizes tool life with reduction of thermal shock.
  • Completely washes away chips from surfaces.
  • Provides more thorough cooling to prevent chip welds.
  • Water-based flood coolants offer greater safety than neat oils


  • Uses a high volume of cutting fluid.
  • Cannot reach chips in deep bores or other tight spaces.
  • Potential for microorganisms to grow in the sump for water-based fluids. However, high-quality coolant formulas like those in the TRIM® line naturally resist their formation. 

High-Pressure Jet and Through Tool

A more refined, higher pressure, and concentrated version of flooding, specialized coolant pump systems shoot cutting fluid in high-pressure streams, often with more than 1,000 psi (pounds per square inch) of force. This is the best method for clearing chips, making it particularly effective for drilling operations where concentrated streams of fluid are aimed directly into a cutting zone. In fact, newer machines actually deliver coolant through the spindle or turret itself

These types of systems, coupled with high speed cutting systems, can generate coolant mist. A mist collection system is important to control the coolant mist. You also want to match the coolant pressure and volume to your cutting tools and operations.

When using this system, look for cutting fluids that are formulated for use in high-pressure systems. Many of them are formulated to leave a thin, but easy-to-clean film on workpieces and reduce mist. They will be optimized to resist foam, and to avoid plugging filters and the coolant systems and tools. Selection of the proper coolant is critical to the success of your high-pressure coolant system and operation.


  • High-powered blasts wash chips out of bores and other tight spaces.
  • Removes chips and debris that other coolant delivery systems cannot reach. 
  • Provides maximum, targeted cooling to the cutting zone and tools.
  • Drastically improves cutting and feed rates for better productivity.


  • May generate mist that lowers the quality of the shop environment and leads to higher coolant consumption.

Minimum Quantity Lubricant (MQL)

Minimum quantity lubricant (MQL) techniques involve putting drops of high-quality cutting oils directly onto the tool. This method relies on using specialty fluid to maximize lubricity. 

Compared to other techniques, MQL requires the least amount of cutting fluid. Also, MQL cannot evacuate chips, so it’s important to invest in air blasting equipment.


  • Very low coolant consumption maximizes the life of the product.
  • Can reduce fluid costs in optimised systems


  • Doesn’t remove any chips or debris without air equipment.
  • Can cause residue buildup.
  • Limited cooling ability of the fluid.
  • MQL fluids can be costly.


This method atomizes specialty cutting fluid into small particles that spray gently onto cutting tools and workpieces. Similar to MQL, it minimizes the amount of coolant used for cutting. However, this specific technique provides more coverage over the workpieces. Some hybrid cooling systems enhance misting and MQL by using cold CO2. This chills the cutting fluid to freezing temperatures for additional cooling abilities. 

Pro tip: This system is ideal for open machines and those without a coolant sump system. Take into consideration that misting, just like MQL, does not evacuate chips without the aid of an air blast. 


  • Provides necessary lubrication across workpieces while minimizing fluid consumption.
  • Keeps coolant costs low.


  • Doesn’t remove chips or debris without air equipment.
  • Limited cooling ability.

Air Coolant 

This system uses blasts of air to clear chips without liquid lubricant. It’s commonly used in conjunction with MQL and misting. It provides no lubricity, but does offer some cooling ability. 

Using carbon dioxide instead of air can enhance cooling ability, as carbon dioxide gas is blasted at below freezing temperatures. 


  • Allows chip evacuation without any coolant consumption.
  • No fluid management necessary.
  • Eliminates coolant in waste stream.


  • Doesn’t provide any lubrication benefits.
  • Only works on limited materials.
  • Provides no protection for cutting tools or machines.

The Best CNC Coolant Delivery System

CNC machining offers unparalleled production efficiency. But these benefits are not possible without the right coolant — and the right coolant delivery system. 

Ultimately, the best coolant delivery method is the one that’s tailored to your specific CNC operation. If you need unrestricted cooling and lubricity with many chips to wash away, flooding and jet methods may be the most ideal. However, MQL and misting techniques are best for operations that want to limit coolant use and management. 
Call +1 800-537-3365 or email [email protected] to learn more about how high-quality cutting fluids can enhance your CNC operation.