Stamping aluminum

[rws]

I would like to stamp out a "fan" out of sheet aluminum. Something like a four blade and about 12 inches in diameter. Would I need a male and female matching stamp to create this? It won't be turned at high RPM, so perfect balance isn't needed. Any ideas?

[Evan]

A hardwood die set will work fine for that. You need to allow for some springback unless you are using dead soft O condition 1100 series alloy.

Wait. Did you also mean to actually cut the piece too?

[Peter S]

A press tool (hardened punch, die, stripper etc) is suitable for large quantities, but (very) expensive. Yes you need a punch and die if you are blanking a part out of sheet, and probably a stripper if you are punching holes as well.

I would go for laser cutting, this way you can develop and run your part without any hard tooling. Excellent for production runs of several hundred. Otherwise plasma or water cutting will also do it. A turret punch will also do the job, a good one can punch any shape you can imagine. Bandsaw?

If you are forming the part (as Evan suggests), then I have heard of a rubber mat being used in combination with the forming tool. They also make castable metals specifically for this job.

Probably lots more on this subject, I haven't been around a press tool for about 30 years.

[Evan]

If the part is to be made from thin aluminum sheet like aluminum flashing it can be cut (stamped out) but not formed using an old heidelberg style platen press. I ran one as a child in an attic sweat shop (not kidding) and it would cut a pencil in half after instantly smashing it flat. The punch is made of a hardwood plate with knife edge steel ribbons inset in the wood in a kerf cut by a slitting saw. The platen was another piece of hardwood but these days a piece of hard plastic would work well. It will easily cut .020" aluminum flashing at the rate of about 1 every 4 seconds. Good way to lose a finger or two if you lose concentration.

[J Tiers]

Tooling questions always deal with quantity.

How many you need?

just one? saw/laser/waterjet/tinsnip it out, and form with any means you like.

Or put cut out flat blades in a machined hub. I'd suggest a pin through each to hold.

Want lots?

Then you are into tooling. The die to cut a 12" diameter fan will need to cut a total periphery a lot longer than it seems, which can get into serious tonnage with the gauge of metal needed to form up into a stiff blade. Maybe an outline of even 60" is not unreasonable, depending on the type of blading. That may take a large press.

[rws]

I was thinking on cutting the overall shape, make the cuts for the blades themselves, then press/form the fan. Only need a few, maybe 6 or so.

[PTSideshow]

Replacement fans at graingers since it is such a small number, That way you don't have to worry about truing them up and balancing them etc. or attaching to a hub. Or most refrige supply places.

[Evan]

For that many you can buy entire working fans made in China, remove the blades and use the motors to make disposable paint stirrers.

[Scishopguy]

Replacement fans at graingers since it is such a small number, That way you don't have to worry about truing them up and balancing them etc. or attaching to a hub. Or most refrige supply places.

There is no sense reinventing the wheel. There is a lot of tooling expense and work involved in making these yourself, even if you cut a few corners. Grainger, Small Parts, McMaster-Carr, or even on the surplus market these are available in many shapes and sizes. Man, your workin too hard.