A Guide to Carbide Insert Coatings: PVD, CVD, and More

A carbide insert coating is a thin layer applied to the surface of a tungsten carbide insert to improve its wear resistance, heat tolerance, and friction properties. Think of it as a protective armor that helps the insert withstand extreme cutting conditions.

Common benefits of coatings include:

• Reduced friction for smoother cuts

• Increased hardness for longer tool life

• Resistance to oxidation at high temperatures

• Improved chip evacuation

Types of Carbide Insert Coatings

1. PVD Coating (Physical Vapor Deposition)

PVD coatings are applied at relatively low temperatures using a vacuum deposition process. Popular PVD coatings include TiN (Titanium Nitride), TiCN (Titanium Carbonitride), and AlTiN (Aluminum Titanium Nitride).

Key Features:

• Thin coating (2–5 µm)

• High hardness and wear resistance

• Best for finishing operations and high-speed milling

Practical Use:

• Ideal for stainless steel and alloy steels

• Common in automotive and aerospace industries

2. CVD Coating (Chemical Vapor Deposition)

CVD coatings are applied at higher temperatures, forming a thicker layer (3–8 µm) on the insert surface. Examples include TiC (Titanium Carbide), TiCN, and Al2O3 (Aluminum Oxide).

Key Features:

• Excellent wear and heat resistance

• Suitable for roughing and heavy-duty operations

• Slightly less sharp edge than PVD inserts

Practical Use:

• Best for cast iron, hardened steels, and high-temperature alloys

• Used in die & mold and general machining applications

3. Multi-Layer Coatings

Some inserts combine PVD and CVD layers to achieve a balance of toughness and wear resistance. These are especially effective in high-speed milling and interrupted cutting operations.

4. Other Specialty Coatings

• Diamond Coating: Ultra-hard, ideal for non-ferrous metals and composites

• TiAlN / AlCrN: High oxidation resistance, excellent for dry machining

The ISO 1832 standard helps identify inserts based on shape, clearance, tolerance, chip breaker, and coating.

Example: CNMG 120408

• C = 80° diamond shape

• N = 0° clearance angle

• M = Medium tolerance

• G = Ground insert

• 12 = Size (inscribed circle 12 mm)

• 04 = Thickness (4 mm)

• 08 = Nose radius (0.8 mm)

Tip: When choosing a coated insert, always match the coating type with your material and operation.

Brand Comparison:

• Sandvik Coromant: High-performance multi-layer coatings, especially for finishing stainless steel

• Kennametal: Excellent CVD-coated inserts for roughing hardened steels

• Iscar: Broad selection of PVD-coated inserts for high-speed milling and finishing

Choosing the right carbide insert coating can dramatically improve your CNC machining efficiency, extend tool life, and reduce costs. Whether it’s PVD for finishing, CVD for heavy-duty cutting, or multi-layer inserts for a balance, understanding coatings is key.

Explore CNC Tools Depot’s marketplace today to find high-quality, brand-certified carbide inserts for all your turning and milling operations.