There is an electrical contacts manufacturer. He manufacture such contacts:

enter image description here

I think he use a pipe as a billet. But how does the stamp works? Can someone tells how to stamp a thin copper pipe and provide some examples?

  • $\begingroup$ have the pipe on a former or mandrell. $\endgroup$
    – Solar Mike
    Jan 31, 2023 at 15:28
  • $\begingroup$ Afew processes are involved , like cold heading and turning. $\endgroup$ Jan 31, 2023 at 16:23
  • $\begingroup$ it may be trade secret ... ask the manufacturer, you may get a response $\endgroup$
    – jsotola
    Jan 31, 2023 at 16:47
  • $\begingroup$ get a cardboard tube and scissors ... do some brainstorming $\endgroup$
    – jsotola
    Jan 31, 2023 at 16:49
  • $\begingroup$ Are you just curious about how this is done or are you looking to do this yourself? Stamping 3D shapes is not something you just do. There's math and mechanical analysis involved. Stamps and dies are prohibitively expensive unless you are in mass production. $\endgroup$
    – DKNguyen
    Jan 31, 2023 at 18:48

1 Answer 1


Metal can be very ductile but it is difficult for humans to imagine since we don't normally work with forces that large. Look at how an aluminum soda can is made. It's like forming putty.

To me those do not look like they are stamped from a pipe, though I suppose it's possible to put the pipe on a mandrel with cutouts and then have a complex concentric punch move radially inwards to stamp all the slots and another to fold in the spokes. It is also possible that these steps may have been done at the same time.

But it could also be that a ring with spokes was stamped from a flat sheet and then a second stamp folds up the spokes, though in practice this would probably be done in a single step since it's easy to fixture a big piece of sheet metal but very difficult and time consuming to fixture a complex shape for the second stamping.

It's not necessarily like punching something out of paper since metal is ductile so forming is possible, so what you start with might not resemble what you end up with all that much. It might not even start out as a piece of sheet metal. It is also possible that this part was not punched and folded from sheet metal, but stretched and formed from something going through sheet metal.


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