The Impact of Coatings on Carbide Cutting Tool Inserts

The coatings on carbide cutting tools and inserts brings considerable advantages that improve the performance and longevity of each insert. The benefits to the bottom line are tangible almost immediately, and can be game-changing in the long run.

Here are the most significant benefits to be realized by applying  coatings on carbide cutting tools:

Increased Wear Resistance

The proper coatings on carbide cutting tools provide a hard surface layer that resists wear, abrasion, and erosion during cutting operations. This helps keep tools sharper over a longer tool life.

Friction Reduction

Special coatings on carbide cutting tools are formulated to reduce the friction between the tool and the workpiece, reducing the heat generated by the cutting process. Lower friction reduces tool wear and frequency of breakage while improving the finish quality of the cut.

Improved Thermal Resistance

High-performance coatings improve the tool’s thermal resistance during high-speed machining. Tools are protected from heat damage, resulting in longer tool life under high-speed operations.

Enhanced Chemical Resistance

Tool coatings can provide a layer of protection between a carbide insert and a workpiece that is chemically reactive to it. Where an uncoated carbide insert might experience rapid degradation, a coated tool will confer all the desired benefits of carbide without oxidation or diffusion. 

Prevention of Built-Up Edge

Coatings on carbide cutting tools can help prevent the formation of a built-up edge, where workpiece material adheres to the cutting edge, leading to poor surface finish. Coatings with low adhesion properties can prevent material from sticking to the tool, ensuring cleaner, more consistent cuts.

Increased Efficiency

The combination of reduced wear, lower friction, and higher thermal resistance allows coated carbide inserts to operate at higher efficiency. This results in faster production cycles and increased productivity.

Extended Tool Life

Coated inserts generally last longer than uncoated, reducing the frequency of tool changes. This lowers tool costs and minimizes machine downtime. 

Improved Surface Finish

The smoother, harder surface of a coated tool produces better surface finishes on machined parts, reducing the need for secondary finishing operations.

Choosing the Right Coating

Enhancing performance by improving wear resistance, reducing friction, increasing thermal and chemical resistance, and allowing for higher machining speeds should be universally appealing to all machinists, regardless of what they are machining. But with all the coatings available, how do you choose the right one for any given application?

The answer involves selecting the appropriate coating based on the material being machined and the operating conditions. Here is a basic primer on the effects of various coatings on carbide cutting tool inserts:

Titanium Nitride (TiN) 

The original “gold standard” coating, TiN gives good overall protection and performance enhancement characteristics.

Thermal resistance

Oxidation resistance to 600°C

Anti-adhesion, prevents Built-Up Edge (BUE)

Titanium Carbonitride (TiCN) 

Incorporating carbon, TiCN is an enhanced version of TiN, with improved durability in high-speed applications and with abrasive materials like cast iron, stainless steel & others.

Improved wear resistance

Reduced friction

Increased hardness

Abrasion resistance

Cyclic-stress resistance for clean interrupted cuts

Aluminum Titanium Nitride (AlTiN) and Titanium Aluminum Nitride (TiAlN) 

AlTiN and TiAlN coatings are particularly valued for their high thermal stability and oxidation resistance, making them ideal for high-speed machining and difficult-to-cut materials.

Extraordinary thermal resistance

High-speed cutting/High feed rates
Superalloys, hardened steels, titanium

Diamond Coatings

While not suitable for cutting ferrous materials, diamond coatings offer unparalleled wear resistance when machining composites, graphite, and aluminum alloys.

Superior hardness

Abrasion resistance
Extended tool life

Custom Coatings

Which coating is the best for your particular situation? The answer is not always cut and dry. There are many factors involved, including characteristics of the workpiece, particulars of the cut itself, and many other variables. They all must be taken into consideration in order to make the most informed decision. 

Custom tooling experts like Knight Carbide can help narrow your coating options and even implement small-batch testing to compare how performance and tool life are affected by each coating option