The Impact of Coolant and Lubrication on Tungsten Carbide Cutting Tools

In the world of high-speed machining and precision manufacturing, tungsten carbide cutting tools are the workhorses behind accurate and efficient operations.

These tools are known for their exceptional hardness and resistance to wear. But even the best tool needs a little help to perform at its peak—and that’s where coolant and lubrication come in.

Using the right coolant or lubricant doesn’t just reduce heat. It improves the cutting process, protects the tool, enhances surface finish, and extends tool life.

For decision-makers in machining industries, understanding this relationship is key to cutting costs and boosting productivity.

In this article, we explore how coolant and lubrication affect tungsten carbide cutting tools, and what best practices you should follow to get the most out of them.

Why Heat Is the Enemy of Cutting Tools

When tungsten carbide tools cut metal, the friction between the tool and the workpiece generates intense heat—especially at high speeds. If this heat is not managed properly, it can lead to:

Premature tool wear
Built-up edge on the cutting surface
Poor surface finish
Micro-cracking or chipping of the tool
Material welding to the tool

Even though tungsten carbide can withstand more heat than HSS (High-Speed Steel), it still suffers under extreme conditions. That’s why coolant and lubrication are essential.

What Does Coolant Do in Machining?

Coolant is a fluid used during machining to control temperature, flush away chips, and sometimes add lubrication. Common coolants include:

Water-based solutions (soluble oils, semi-synthetics)
Straight oils (cutting oils)
Synthetic fluids

Coolants serve three primary purposes:

Cooling: Reduces the temperature at the cutting zone to prevent thermal damage.
Flushing: Clears chips from the cutting area to prevent recutting.
Lubricating: Reduces friction between tool and material.

By keeping the cutting environment cool and clean, coolant helps carbide tools cut more efficiently and last longer.

Lubrication vs. Coolant: What’s the Difference?

While coolant focuses on temperature and chip removal, lubrication focuses more on friction reduction.

Lubricants may be oils, mists, or solid-based, and are especially useful in operations where:

Surface finish is critical
Tools need to cut sticky or ductile materials (like aluminum or copper)
There’s a risk of built-up edge
High-speed or dry machining is used

In many operations, coolant and lubricant are combined into one solution to offer both heat control and surface protection.

Key Benefits of Using Coolant and Lubricants with Tungsten Carbide Tools

Here’s why proper fluid use is critical for decision-makers aiming for long-term machining efficiency:

1). Reduced Tool Wear

Fluids act as a barrier between the tool and the workpiece, reducing direct friction. This slows down abrasive wear and minimizes micro-cracks in the cutting edge.

2). Longer Tool Life

With better heat control, the tungsten carbide retains its hardness longer. This leads to fewer tool changes and lower replacement costs.

3). Improved Surface Finish

Proper lubrication avoids tearing or smearing of the workpiece material, leading to smoother surfaces.

4). Less Built-Up Edge (BUE)

Coolant and lubricants prevent sticky materials from welding to the tool, which affects part tolerance and surface quality.

5). Better Chip Control

Coolants help in breaking and removing chips effectively, especially in high-speed or deep cuts.

Choosing the Right Coolant or Lubricant for Carbide Tools

Not all fluids are created equal. The choice depends on your material, speed, and process type.

Here’s a quick comparison:

Best Coolant Types by Application

Application	Material	Recommended Fluid
High-speed milling	Steel, stainless steel	Semi-synthetic coolant
Turning & boring	Cast iron, tool steel	Straight cutting oil
Finishing	Aluminum, brass	Light oil or micro-lubrication (MQL)
Hard machining	Titanium, Inconel	High-pressure coolant with additives

Tip: Always check if the fluid is compatible with carbide. Some fluids may promote corrosion if not maintained properly.

Dry Machining vs. Wet Machining with Tungsten Carbide

Dry machining means no coolant is used—relying only on air or tool coatings to manage heat.

While it works in some operations, it’s not ideal for heavy-duty machining or abrasive materials.

Wet machining with coolant provides more reliability and tool longevity.

Tungsten carbide tools, though heat-resistant, still benefit from coolant when cutting at high speeds or under load.

How Coolant Delivery Affects Performance

Even with the right coolant, how it’s delivered matters. There are several methods:

Flood coolant: Covers the cutting area completely. Good for general-purpose operations.
High-pressure coolant: Ideal for deep hole drilling or cutting hard materials.
Through-tool coolant: Coolant flows inside the tool and exits near the cutting edge. Highly efficient.
Minimum Quantity Lubrication (MQL): A small mist of lubricant is applied directly. Great for eco-friendly and low-heat applications.

Through-tool coolant is particularly beneficial for carbide drills and end mills in deep cuts or small diameters.