What are the differences between CNC carbide inserts of different natures?

CNC carbide inserts come in different "natures" depending on their geometry, grade, coating, and application purpose. Each difference affects performance, tool life, and machining results.

1.By Base Material (Grade / Binder Content)

General-purpose carbide (WC + Co): Standard tungsten carbide with cobalt binder, good balance of toughness and wear resistance.

Micro-grain carbide: Finer grain size, higher hardness, good for finishing and high-precision machining.

High-cobalt carbide: More cobalt → higher toughness (shock resistance), but slightly lower wear resistance (used for interrupted cuts).

Low-cobalt carbide: More wear resistance, used for continuous cutting of harder materials.

2.By Coating

Uncoated inserts:

Very sharp edges. Used for aluminum, copper, plastics, or where built-up edge is a problem.

CVD coated (Chemical Vapor Deposition):

Thick, wear-resistant layer (TiN, TiCN, Al₂O₃).

High wear resistance, good for steel and cast iron.

PVD coated (Physical Vapor Deposition):

Thinner, sharper coating, less edge buildup.

Used for stainless steel, high-temp alloys, finishing.

Special coatings (Nano-layer, DLC, Diamond):

For aluminum, composites, and superabrasive cutting.

3.By Cutting Edge Geometry

Sharp positive rake (high rake angle):

Lower cutting forces, good for aluminum and stainless steel.

Negative rake:

Stronger edge, handles high feeds and heavy cuts.

Ground sharp edges:Precision finishing, aluminum machining.

Honed / chamfered edges:For heavy-duty steel cutting, prevents chipping.

4.By Chipbreaker Design

Finishing chipbreakers: Light cutting forces, small chips.

Medium chipbreakers: Balanced, for general-purpose cutting.

Roughing chipbreakers: Stronger, handle heavy cuts and high feed rates.

5. By Application

Steel inserts (P-grade): High wear resistance, optimized for medium-to-hard steels.

Cast iron inserts (K-grade): Tough coatings, handle abrasive cast iron.

Stainless steel inserts (M-grade): High toughness, resist built-up edge.

Non-ferrous inserts (N-grade): Sharp, uncoated or diamond-coated, for aluminum and copper.

High-temp alloys (S-grade): High toughness + heat resistance (nickel, titanium).

Hardened steel inserts (H-grade): Ceramic, CBN, or PCBN-tipped for hard turning.

Summary:

Grade = toughness vs. wear resistance balance.

Coating = surface protection & friction control.

Geometry & chipbreaker = determines cutting force, chip control, and edge strength.

Application-specific design = matches the insert to the work material.