Glossary

Cold forming is a high-speed metalworking process used to manufacture fasteners and other components by plastically deforming metal at or near room temperature. Instead of heating the material to soften it, cold forming relies on powerful mechanical presses and precision dies to force the metal into the required shape. Because the process works the metal while it remains cold, it preserves and even enhances material strength through work hardening, making the finished fasteners stronger and more durable than those produced by machining or hot forming.

The process begins with wire or rod stock, which is drawn to the proper diameter for the fastener being produced. The stock is cut into blanks and then fed into a multi-station cold forming machine. The first major step is heading, where the end of the blank is upset or deformed to create the head of the fastener. The next step is often extrusion, which forces metal to flow into die cavities to shape the shank or special features of the fastener. Excess material may then be removed through trimming, ensuring precise geometry. Finally, thread rolling is performed by pressing the blank between dies that displace material to form threads rather than cutting them, producing stronger threads with excellent surface finish.

The advantages of cold forming are considerable. It is highly efficient, producing minimal waste since the metal is displaced rather than cut away. The process is extremely fast, capable of producing hundreds of parts per minute, making it well-suited for high-volume production. Because the material is work-hardened, the resulting fasteners have superior mechanical strength, fatigue resistance, and reliability. The process also achieves tight dimensional tolerances and smooth surface finishes, which reduces the need for secondary machining.

However, there are also disadvantages. The dies and tooling are costly to design and manufacture, which makes cold forming less economical for small production runs or prototypes. The process is best suited to parts with relatively simple geometries; very large fasteners or complex shapes are better made by hot forging or machining. Additionally, because cold forming strain-hardens the metal, secondary operations such as drilling or machining can be more challenging.

In terms of applications, cold forming is one of the most important processes in the fastener industry. It is used to produce bolts, screws, rivets, nuts, and specialty fasteners in massive volumes, with consistent quality and strength. Industries such as automotive, aerospace, construction, and general manufacturing depend on cold-formed fasteners for safety-critical and cost-sensitive applications.