Do Tool Coatings Make A Difference?
Cutting tools come in many shapes and sizes. Picking the right one for the task at hand can be difficult. With a variety of styles to choose from already, the matter is further complicated when you consider each of these tools could have any of a number of coatings. This article will aim to help you parse out which one, if any, will fit your needs when it comes to those coatings.
Tool coatings aren’t just for show, though they come in an array of colors. From keeping your tools sharp longer to holding onto lubricant, coatings can be extremely useful. To determine which coating will work best for you, you’ll need to know a bit about what they do.
The first thing to note is that there are two basic kinds of coatings: Physical Coatings and Chemical Coatings. Physical coatings, or physical vapor deposition (PVD) coatings work well at lower temperatures. The coatings are usually thinner, so they can heat up and wear off easier at higher temperatures. This suits them well for use on tools that already run at lower temperatures, like high speed steel tools. Common PVD coatings include Chromium Nitride, Titanium Nitride, Titanium CarboNitride, and Aluminum Titanium Nitride coatings.
Chemical coatings, or chemical vapor deposition (CVD) coatings are applied at extremely high temperatures (around 18000° F) using plasma or photo-induced processes. This results in a very strong and even coating that holds up well to high temperatures.
Titanium Nitride, or TiN coatings appear golden. Due to the hardness and resistance to heat of these coatings, they’re used very commonly on average drilling tools.
Titanium CarboNitride (TiCN) coatings induce very little friction when tooling most materials and are ideal for those materials that tend to gum up your un-coated tools. They’re also harder than Titanium Nitride coatings, so they will increase the longevity of your tool.
Chromium Nitride coatings appear silver and shiny. They’re known for reducing friction, much like TiCN coatings, but can be run at higher temperatures without losing the benefits.
Aluminum Titanium Nitride (AlTiN) coatings appear dark grey. They’re harder than TiN coatings and can be used at much higher temperatures without losing that hardness.
Titanium Aluminum CarboNitride (TiAlCN) coatings appear pink. These coatings are what is known as a nano coating, which makes them exceptionally hard and allows them to maintain low friction at very high temperatures. This makes them ideal for use on materials such as super alloys, stainless steel, cast iron or aluminum.
Oxide coatings appear black and are often used on tapping tools as they help the tool retain lubrication well on their surface.
Bright or gloss coatings are actually uncoated but polished to a mirror-like sheen. The benefit of not having a coating is they can be sharpened more than coated tools can. Sharpening coated tools can grind away the coating.