The TiAlN drill bit is a coated drill bit. TiAlN is a mixed compound. It contains Titanium, Aluminium, and Nitrogen. This coating is applied on the drill bits in order to improve durability, reduce friction and improve thermal resistance. Normally, TiAlN drill bits are violate in colour and mostly used for harder metals.
What Is TiAlN Coating On Drill Bit?
Drill bits are coated with Titanium based compounds in order to improve physical properties. TiAlN consist of Titanium, Aluminum and Nitrogen. The TiAlN drill bit can identify by the violet-colored drill bit. As mentioned earlier, the TiAlN drill bit is a type of Titanium drill bit. It means an HSS drill bit has coated with TiAlN. HSS, cobalt drill bits can coat with TiAlN at temperatures of 450o – 475o. TiAlN coating value adds to HSS drill bits like TiN and TiCN coating. Materials include in TiAlN coated drill bits;
- High-Speed Steel,
- Stainless Steel,
- Alloy Steel
The high-performance coating and point angle are exclusively combined to create specific design and cutting characteristics. The most popular drilling points of drill bits are;
- 118o – Can use on less expensive general-purposes drilling purposes
- 135o – 135o of drill bit angle is suitable for harder materials like hardened steel
Because the 135° split point grinding tip on TiAlN drill bits offers exact centering and lower drilling pressure on tougher metals
The TiALN coating is extremely resistant to wear and has an approximate hardness is 85 HRC.
Depending on the work you want to do, choose the suitable flute type. But mostly TiAlN drill bits have;
- Twist or spiral
- Double U shape flute type.
*Double U shape flutes design clears chips effectively.
The common shank type is the straight shank type. Hex-shank-type also bits are available.
What Material Can Be Drilled Using TiALN Coated Drill Bit?
TiAlN Drill bits are generally used for drilling metal and stronger alloys. Generally, materials with a hardness of 67-70 can be drilled with using TiAlN.
And the coating can transfer excess heat to the coolant and chips during drilling rather than the drill bit itself.
Below materials can be drilled using TiAlN drill bits.
- Stainless steel,
- Titanium alloy,
- Cast steel,
- Iron,
- Aluminum alloy
- Copper.
In other words, drill bits with TiAlN coating should last longer than drill bits without coating, and you can frequently drive them quicker too. It prolongs edge retention and reduces friction, among other advantages.
Why TiAlN Is Coated On Drill Bit?
The primary objective of coating a typical drill bit is to increase its efficiency and life. It also applies to TiAlN drill bits. Extreme hardness and outstanding oxidation resistance are provided by TiAlN coating. This coating performs well in applications requiring extremely demanding cutting tools, particularly when tools are being used to their absolute limit.
Especially since TiAlN is heat resistant, it prevents the drill bit from breaking due to high temperature. It is excellent in drilling applications for steels, stainless steels, and non-ferrous materials and has exceptional abrasion resistance. Since the hardness of these materials is high, the temperature generated during drilling with an uncoated drill bit is directly absorbed by the drill bit material.
TiAlN Drill Bit Geometry
TiAlN drill bits do not have a specific geometry. It is a coating. Hence it can apply to any drill bit geometry. When using this coating, drill bits’ characteristics will improve, and geometry will protect from friction, heating, and wanderings.
How Is TiAlN Coat Damaged?
TiALN is also a very hard compound that can be used as a coating, like TiN and TiCN. It will damage or remove because of hard drilling. Therefore, suitable intervals must take when hard drilling.
And also, it must start from a low speed and continue until a suitable high speed because of high-speed drilling also a reason for the damage to the coat.
The re-sharpening process removes the coating from the drill bit, and it will become a primary drill bit. Actually, any type of coated drill bits is not allowed for the re-sharpening.
What Is HSS-TiAlN Drill Bit?
TiAlN is a sort of external hard compound coating, while HSS is a type of drill bit material. These two elements come together to form an HSS-TiAlN drill bit, which serves as a thermal barrier and reduces friction to make chip evacuation easier.
What Is Cobalt TiAlN Drill Bit?
A cobalt drill bit is a type of drill bit you can buy in the market. As the name suggests, this drill bit contains a certain percentage of cobalt. There are two types according to the percentage of content.
- M35 – Contains 5% of cobalt with alloy
- M42 – Contains 8% of cobalt with alloy
Normally, cobalt drill bits are not coated and baked in an oven at the end of the manufacturing process. It gives the steel’s surface with dull gold appearance. Cobalt drill bits can drill more hardened metals. Such as; bronze, cast iron, stainless steel, and titanium. The TiCN coating will improve the drilling ability.
As mentioned earlier, since TiAlN is a hard compound, it enhances the properties of a cobalt drill bit.
Can You Sharpen TiAlN Coated Drill Bit?
Sure, but the coating will be removed or damaged during the re-sharpening procedure. As a result, efficiency will drop. Only the HSS drill bit will remain in the end. Hence, it is not a good idea to re-sharpen a drill bit with a TiAlN coating.
TiCN vs TiALN Drill bits
TiCN
Coating – Titanium Carbon Nitride
Color – Blue – gray
Surface Roughness – 17
- Has a strong, smooth surface that improves wear and increases edge resistance.
- TiCN functions well on drills and reamers where moderate temperatures are created at the cuffing edge because it has strong adhesion, hardness, and chip resistance.
TiAlN
Coating – Titanium Aluminum Nitride
Color – Violet and black
Surface Roughness – 40
- Reflects heat away from the tool and workpiece and back into the chip. It is a suitable option for interrupted cuts due to its greater ductility.
- The main advantages are increased production levels at faster feed rates and longer tool life in high heat situations.
TiAlN vs. Cobalt Drill bits
| Characteristics | TiAlN | Cobalt drill bit |
| Material | Tough alloy steel weld seams Hardened steel | Alloy steel with 5-8% Cobalt |
| Color | Violet and black color | Dark color appearance |
| Heat Resistance | Moderate | High |
| Wear resistance | Very good | Excellent |
| Materials can drill | Tough alloy steel Weld seams Hardened steel | Tough alloy steel Weld seams Hardened steel |
