Cold heading is a process that uses molds and punches to make parts of various shapes from metal wires. The process can reliably reproduce precise specifications. Cold heading does not use heat to reshape the raw material; it uses the force driven by a punch to push the material through the mold into a new shape.
The cold forming process with a drill, another name for cold heading, starts with a wire. Depending on the end use of the product, the wire can be different grades of steel, copper, brass, or other alloys. The wire is fed into the processing process, and then cut with a cutting machine, and its length can produce a wire volume exactly equal to the amount of material required for the finished product. The process continues to form the head of the finished product. The cold heading process is mainly used for bolts, screws and other fasteners, which must have a specially shaped head. The shape of the head can be manufactured with a mold, a punch, or a combination of the two. If the end of the punch is shaped rather than flat, this is part of the shape of the finished head.
The design used for cold heading usually refers to the number of steps in the process. The two-die three-blow process means that the wire feed is pressed into two different die shapes and impacted by three different punches. The number of hammer strokes required is related to the size of the diameter reduction required from the wire feed to the mold. Generally, one purge cannot effectively reduce the size by more than 30%. If necessary, the cold-headed parts can be threaded or machined after the cold-heading process is completed. Finished parts are usually heat treated to harden and anneal the metal. In order to complete the part, the surface can be cleaned to remove residual lubricating oil, or in some applications, coating or electroplating cold heading is a form of extrusion, but it has an advantage over other extrusion methods-it can be used For materials that are not heat resistant. It is more cost-effective than milling, machining or etching because it does not waste any raw materials. It is also lower than hot upsetting because it does not require heat. The process is fast, but some shapes cannot be produced without heating, and some materials have no elasticity without heat, so they are not suitable for cold forming.
