How are these shaped?

I’ve seen some grainy videos from some time ago about the extrusion and coiling production of a basic plastic Slinky, but can’t find anything on the shaped versions above.

My initial thought was that they were maybe pressed into shape from a blank cylindrical Slinky, but after inspecting one, I couldn’t see any parting lines if it were a mold. Can they coil the plastic extrusion straight into those shapes, like the star for example?

Any help would be appreciated!

I suspect the coil that the material collects on is just wrapped onto a shaped coil instead of the usual cylindrical one and the material flows around it OK. The corners still have fairly generous radii.

The best shape control is most likely to have the extruder head bend these directly into shape. From what I have seen factories do with CNC bending and pasta extrusion, that may very well be possible.

Thanks guys.

Not sure why my initial thought was to press it into shape. Gotta love a nice, generous radius.

post rescended

It doesn’t make your nickname less dubious :sunglasses:

Thanks for that video.
I am looking for an expert on metal injection molding at the moment.

We are looking to produce a large chandelier with the design of a looped 3D bent strip (think of those black race tracks for kids) but around 3m long.
Ideally it will be made of a thin aluminum profile, say 100 x 15mm.
Now the only 3D Freeform bending machine I currently know of is at Rainier in Wisconsin, but they only do circular pipes.
Besides 3D printing, I would like to know if anyone has advice on how to manufacture such a luminaire.
I am looking at technologies such as superplastic forming but ideally this will be made of one piece aluminum to be anodized.

Filmed with a potato, but you get the idea

Wood form. Cut your spiral with a 30-40mm deep groove, 17mm wide. If your spiral is a cylinder in shape, pretty easy. If cone shaped, the forming mandrel will need to be adjustable. The motor to turn the wood form will need to be low rpm, very high torque.

Good god, my phone takes better videos.