polypropylene sheet in hexagon shape??? 2

[slawco]

Can anybody tell me if technically is possible to produce polypropylene sheet in continuous hexagon (spiral) shape?
To be more clear I'm attaching the image of shape.

Thank you in advance.
Jaroslav

 

[MikeHalloran]

I don't see the 'hexagon' as in 'six sided polygon'.

The pictured object looks like the kind of thing you could, theoretically, do with a rotating nozzle on an extruder... if there were such a thing. I'm not aware that there is, or isn't.

but you'd probably make a lot of scrap before you got the nozzle temperature stabilized... _if_ you ever got it stabilized.

OR,

You could skive it off the end of a rotating bar in a lathe.

You didn't give us a clue how big and how thick this 'sheet' has to be. The dimensions affect the cost of the tooling, and the likelihood of failure.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

I don't see a hehagon.

The shape drawn can be injection moulded, but the mould will be expensive as it will need very large side cores.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[slawco]

Mike, you are absolutely right, it had to be helix not hexagon. My apology.
The size of sheet has to be at least 30 cm. wide and 0.8 mm. thick
Thank you very much for your reply.
Jaroslav

 

[IRstuff]

You're describing a plastic slinky, albeit the run is considerably wider:

http://www.madehow.com/Volume-3/Slinky-Toy.html

TTFN

FAQ731-376

 

[Compositepro]

You could possibly extrude a straight strip through a slot die and use tapered pull/callender rolls to stretch one side more than the other. There would be lots of details to work out.

 

[Demon3]

It would be an elegant solution to simply extrude from a slit die and cool one side way faster than the other. The differential shrinkage should give you some sort of spiral (hard to get it consisten though).

There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell

 

[MikeHalloran]

I don't think you can get a rod that big, but I think you could skive it from the face of a circular sheet blank held in a big-ass lathe.

How many turns do you need... and how will you handle it as it's produced?



Mike Halloran
Pembroke Pines, FL, USA

 

[slawco]

Thank you everyone for help.
I need about six continuous turns and later it has to be precut and folded into some product (patent pending)
I just needed to know if technology to create something like this exists.
It's possible to make this from separate sheets but it would have been much fancier to do it from one piece.
Thank you anyway.
Jaroslav

 

[patprimmer]

You could injection mould cylinders 30 cm in dia, say 2 cm thick and skive off that.


Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[corrosionman]

slawco buy a sheet of pp at required thickness. cut a numbe of discs of required od. put one radial saw cut weld the required sides together and BIngo. you got what you want. Cheers DW