1. Start With the Workpiece Material

During cold heading, the metal blank undergoes significant plastic deformation. Different materials have different levels of hardness, ductility, and work-hardening behavior, which affects the requirements for the forming dies.

For example, carbon steel generally offers good cold-forming characteristics, while stainless steel may experience more pronounced work hardening and adhesion during forming. Aluminum and copper alloys have their own forming characteristics.

Before selecting the dies, it is important to confirm the material grade, wire specifications, and material condition. Product dimensions alone are usually not enough to determine the right tooling.

2. Select the Die Based on Product Geometry

2.1 Start With the Product Drawing

Product geometry directly affects die cavity design and the forming method. Pay close attention to head dimensions, shank diameter, length, recesses, cross-section changes, and dimensional tolerances.

A standard hex-head bolt and a fastener with a flange, recess, or special head may both be produced by cold heading, but their die designs can be quite different.

The more complex the deformation, the more attention needs to be given to die design and the forming sequence. Providing a complete product drawing is therefore much more useful when ordering dies than simply providing the product name.

2.2 Consider Each Forming Operation

In multi-station cold heading, the final product is normally formed through several operations. For example, one station may perform preforming, while later stations complete heading, extrusion, or other localized forming operations.

If the deformation is not distributed properly between stations, the load on a particular die may increase and affect subsequent forming operations. Die selection should therefore be considered together with the complete forming sequence.

3. Choose the Right Die Material and Structure

Common materials used for cold heading dies include:

Die structure also matters. In long-term production, areas exposed to high wear or stress require careful design. Maintenance and replacement should also be considered when selecting the tooling structure.

4. Make Sure the Dies Match the Cold Heading Machine

Dies do not work independently. They work together with the punches, feeding system, transfer mechanism, and cold heading machine throughout the forming process.

When selecting dies, first check the machine's station configuration, die mounting dimensions, stroke, forming capacity, and workpiece transfer method. If the machine is changed, existing dies may not always be suitable for direct reuse.

What Information Should You Provide When Ordering Dies?

When requesting a quotation or custom die design, provide the product drawing, material specifications, blank dimensions, dimensional tolerances, and the main parameters of the existing cold heading machine.

For a newly developed part, it is also useful to provide the target production volume and existing forming process. Complete technical information helps the tooling supplier determine the appropriate die structure and forming sequence.

5. Look Beyond the Initial Die Price

The purchase price of a cold heading die is only one part of the overall tooling cost. For products manufactured over the long term, die durability, maintenance requirements, and dimensional consistency are also important.

A lower-priced die that requires frequent adjustment or replacement may not have the lowest overall cost. The right die material and structure can help reduce unnecessary downtime and tooling adjustments.

For standard fasteners, established forming experience can often provide a starting point for die selection. For complex or newly developed parts, it is generally better to have the tooling supplier develop the die based on the product drawing and machine conditions.