Advancements in Coatings for Cutting Tools: Which One is Best for Your Application? - TGKSSL

There is a persistent quest for precision and efficiency in a vast majority of manufacturing businesses which has resulted in considerable breakthroughs in cutting-tool technology. Though the underlying material offers the necessary toughness and hardness required, the use of specialty coatings has transformed tool longevity and performance.

Commonly Used Coatings

Several of coatings have become industry standards due to their proven ability to improve cutting tool longevity and performance. The following are some of the most commonly used skins or coatings offered by tool steel suppliers:

TiN or Titanium Nitride – Titanium Nitride is one of the earliest used coatings and is still widely used. The coating or skin is easily recognizable mainly due to its gold color. Titanium Nitride excels in general-purpose machining of materials like cast iron, softer steels, and non-ferrous metals. It is relatively affordable which makes it a very attractive option for many applications.

TiCN or Titanium Carbonitride – This is a coating that has built upon the success of TiN and offers greater hardness, as well as better abrasive wear resistance because of the carbon included in its structure. The coating is graying-blue and is effective for machining harder materials like alloy steels and stainless steels at moderate cutting speeds. It is worth inquiring with your preferred tool steel suppliers about the availability of TiCN coatings for such demanding materials.

TiTAIN or Titanium Aluminum Nitride – TiTAIN is easily recognizable by its dark purple or black coloring and forms a protective aluminum oxide layer at high cutting temperatures which further improves the longevity of the tool. Many leading tool steel suppliers offer a wide-range of TiTAIN-coted tools, mainly due to its effectiveness in demanding mold-making, automotive, and aerospace industries.

AlTiN or Aluminum Titanium Nitride and CrN or Chromium Nitride – They are more recent advancements in coatings or skins which offer excellent oxidation resistance and hot hardness, making them a favorite for high speed machining and materials considered as difficult-to-cut such as titanium and nickel-based alloys. Chromium Nitride coatings are particularly effective in machining stainless steels and non-ferrous metals where adhesion can cause problems as most reputable tool steel suppliers can attest to.

Multi-Layer Coatings – Multi-layer coatings have emerged which combines the advantage of different materials in alternating thin layers. This provides a synergistic effect making full use of properties like friction reduction, hardness, and toughness. Some examples include combinations of AlCrN/TiN or TiAIN/TiN.

Factors for Selection

When choosing the ideal coating type for your application, there are several elements to carefully consider:

• Workpiece Material – Its abrasiveness, hardness, and reactivity is a primary determinant.
• Feed Rate and Cutting Speed – Higher feeds and speeds requires coatings with superior wear resistance and hot hardness.
• Coolant Application – The performance and longevity of the coating can be influenced by the type of coolant and its effectiveness.
• Machining Operation – Different operations like turning, drilling, or milling place different demands on a cutting tool.
• Cost – Advanced coatings can offer significant benefits in terms of performance but may incur higher initial costs.

Different coatings or skins provide manufacturers with options to help them prolong the life of their tools and improve their performance. By understanding the properties and applications of the various types of coatings, and considering the demands of your application, you can make informed decisions that can improve your overall manufacturing efficiency.