What Is Polycrystalline Diamond (PCD)?

Polycrystalline diamond (PCD) is a synthetic superhard material made by combining diamond particles with a metallic binder under extremely high pressure and high temperature.

Unlike natural diamond, PCD is engineered specifically for industrial cutting applications. It provides excellent hardness, wear resistance, and cutting-edge stability, making it suitable for machining highly abrasive materials.

PCD tools are commonly used in industries including:

CNC woodworking
Furniture manufacturing
Panel processing
Composite material machining
Non-ferrous metal machining

For woodworking applications, PCD is especially valuable when machining abrasive materials such as:

MDF
Particle board
HPL laminated panels
Melamine boards

These materials can quickly reduce the sharpness of standard carbide tools, while PCD maintains a cutting edge for much longer production cycles.

The Structure of PCD Material

PCD is not a solid piece of natural diamond.

Instead, it is a composite structure consisting of three main parts:

1. Synthetic Diamond Grains

Diamond particles provide the extreme hardness and wear resistance of PCD.

These diamond grains are responsible for maintaining the sharp cutting edge during machining.

2. Cobalt Metallic Binder

The cobalt binder connects the diamond particles together and provides toughness.

The balance between diamond content and binder content affects:

Hardness
Toughness
Wear resistance
Cutting performance

3. Tungsten Carbide Substrate

The carbide substrate supports the PCD layer and allows it to be brazed onto the tool body.

This combination creates a cutting material that is both extremely wear-resistant and mechanically stable.

How Is Polycrystalline Diamond (PCD) Manufactured?

The manufacturing process of PCD tools is more complex than conventional carbide tools.

The performance of a PCD tool depends not only on the diamond material itself but also on the quality of manufacturing, grinding accuracy, and tool design.

Synthetic Diamond Particles and HPHT Sintering Process

The first step is producing the PCD blank.

Synthetic diamond powder is mixed with a metallic binder, usually cobalt, and then processed under:

High Pressure
High Temperature

This process is known as HPHT sintering.

During sintering, diamond particles bond together and form a dense polycrystalline structure.

The final characteristics of the PCD blank depend on:

Diamond grain size
Diamond concentration
Binder composition
Sintering conditions

A higher diamond concentration usually improves wear resistance, while the binder affects toughness and impact resistance.

PCD tool manufacturing flow chart showing HPHT sintering grinding and brazing process

Cutting and Shaping PCD Blanks Into Tools

After the PCD blank is produced, it must be shaped into the final cutting tool.

Common processes include:

Diamond Grinding

Diamond grinding wheels are used because ordinary abrasives cannot effectively machine PCD.

This process creates the required:

Cutting angle
Edge geometry
Surface finish

EDM Machining

Electrical discharge machining (EDM) can be used for precise shaping of PCD components.

It is especially useful for complex geometries and fine cutting edges.

Laser Cutting

Laser technology allows manufacturers to create accurate shapes and profiles for specialized PCD tools.

Brazing

The finished PCD cutting tip is brazed onto a carbide body or tool base.

High-quality brazing is essential because the connection between the PCD layer and tool body directly affects reliability during high-speed machining.