A machined part starts out with a chunk of material large enough to contain the desired part. Then you cut away everything that isn’t the part. This produces chips, which are wasted material. Cutting can also disturb the grain structure of the metal.

Cold forming, however, makes very efficient use of material. It also tends to produce very strong parts, as the material flows into the desired shapes, maintaining its grain structure. And cold forming produces parts rapidly – tens or hundreds of parts per minute.

Some machined parts produced in volume, especially small round work like that made on screw machines, can be made more economically by cold forming. The savings can be greater than or equal to 50 percent, said James Richardson, president of Reed & Prince Manufacturing Corporation. If a cold-formed part can replace a multiple-part assembly, the savings can be even more substantial.

So cold forming is often thought of as a direct competitor to machining. However, a machine shop can sometimes make use of cold forming’s advantages by having the blank for a part cold formed to near net shape and then doing the finish machining. This can save on material cost and processing time. Both Richardson of Reed & Prince and Tapper of Buchanan Metal Forming reported having machine shop customers who order cold-formed blanks.

At Buchanan Metal Forming, Tapper, finds that sometimes machine shops come to him with parts that are particularly challenging to machine, with an internal gear or spline, in a blind hole, for example. “One customer who had the most high-tech of shaper equipment – used to take five mins to cut an internal spline,” said Tapper. “This customer was able to cut that down to two and a half minutes. We did it in six seconds.” Buchanan cold forms the blank for the customer, who then machines it. The drawing shows a cold-forged blank with an internal spline. The broken line indicates the final machined surface.

Most cold forming companies will work with their machine shop customers to determine the correct material and geometry for blanks that will be finish machined.