Drill Bit Coatings - Surface Treatments on Drill Bits
Surface coatings on drill bits allow greater feeds and speeds when operating at higher temperatures, increasing tool life and therefore productivity sometimes by 4 or 5 times. Different drill bit coatings have differing properties to help increase the performance of the cutting tool. Many reduce friction, increase tool lifespan and improve tool performance. The following drill treatments and coatings are commonly used in the Performacut range.
The following characteristics are associated with a steam tempered black oxide coating:
Blackened - Black Oxide: A low-cost black coating which is an industry standard for HSS drill bits. Black oxide coating provides heat resistance and lubricity to high-speed steel, as well as corrosion resistance. Black oxide drills return better tool life expectancy than an uncoated / treated HSS drill bit.
The following characteristics are associated with Bronze Oxide coating:
Bronzed - Bronze Oxide: The industry standard colour for cobalt drill bits. Bronze oxide has similar properties to black oxide including increased lubricity and tool wear, whilst reducing friction. The additional benefits are for tool recognition as a cobalt drill.
The following characteristics are associated with TiN coating:
TiN (Gold) – Titanium Nitride: A gold coloured film of Titanium Nitride with a hardness of approximately 85Rc is deposited on the tool which extends tool life by reducing friction and enables greater speeds and feeds. Lesser quality drills often imitate TiN coating, but more often this is purely cosmetic. Coatings are for use at high speeds where the temperature is high enough to bring the coatings functional use into play.
The following characteristics are associated with TiAlN coating:
TiAlN (Black) – Titanium Aluminium Nitride : This coating has a greater hardness than TiN. A very thin film of AL203 (Aluminium Oxide) is formed on the surface of the TiAlN which greatly increases the service life of the tool, withstanding higher temperatures especially when machining Cast Iron and tough steels. Coatings are mostly effective at high speed rates when the temperature is sufficient for them to increase efficiency.