US Synthetic Bearings Site

PCD Insert (Nib) Sizes

Polycrystalline dies use an abrasion-resistant PCD insert (nib) at the core of each die. A series of “D” numbers were designated to identify the different insert sizes. These sizes range from smaller than a pencil eraser to the size of a hockey puck. Typically the selection of the insert is based on the hole sizes for the die (new and recut sizes).

Carbide-Supported PCD Dies (D15, D18, D21, D24, D27, D30)

• Carbide support reduces cracking
• Wire range of sizes from .020 to .340 inches (0.5 to 8.6 mm)

Most applications can be shoehorned into either “Hard Wire” or “Soft Wire” categories. The figures below can be used as a general guideline for the selection of a PCD insert based on the desired hole size.

Freestanding PCD Dies (D6fs, D12fs, D15fs, D18fs)

• Small dies ranging from .004 to .100 inches (0.1 to 2.54 mm)
• PCD without a tungsten carbide support

What does the ADDMA have to do with wire dies?

ADDMA 8911 refers to the original standards published by the American Diamond Die Manufacturers Association. These standards were established during the early adoption of PCD for use in wire drawing dies to ensure that dies labeled using the D- designation are consistent in size. The standards define the minimum dimensions allowed for each D- designation used on the PCD inserts. Currently, the majority of PCD inserts used in wire dies exceed these dimensions.