Aluminium Extrusion - Tapered Section

Question

Aluminium Extrusion - Tapered Section

(OP)

25 Jul 23 10:08

Tried searching google but struggled to find any information.

I am familiar with the standard aluminium extrusion process for constant section. I am wondering if there is a possibility to extrude a section lets say circular starting at 100mm diameter reducing to 75mm over an 8m length, maintaining a 5mm wall thickness.

I would be interested to know if this is possible and any references to the die design to achieve this.

robyengIT (Mechanical) · Answer 1 · 2023-07-25 12:18:50

with sailboat masts they do but I don't know the tolerances

MintJulep (Mechanical) · Answer 2 · 2023-07-25 12:23:21

Tapered aluminum tube is a thing.

It may begin as straight extruded tube.

Then tapered by other processes.

Constant wall thickness is probably hard.

engineeringspread (Mechanical) · Answer 3 · 2023-07-25 12:29:38

I have seen progressive forming of masts then welded, but never seen a tapered extrusion.

I have noticed reference to variable geometry dies so was curious if this is actually possible.

drawoh (Mechanical) · Answer 4 · 2023-07-25 16:16:39

engineeringspread,

A tapered tube sounds like a good application for welded sheet metal. The 5086 grade is fairly strong in the as-welded condition.

--
JHG

3DDave (Aerospace) · Answer 5 · 2023-07-25 17:57:21

https://forums.sailinganarchy.com/threads/new-mast...

kjoiner (Mechanical) · Answer 6 · 2023-07-26 12:25:32

Hello,

I've seen impact extrusion used to make aluminum baseball bats but in this case the length is less than 1m vs the 8m length you're looking for.

Here's a video of the process:

https://www.youtube.com/watch?v=Aig6-q32Saw

Kyle

engineeringspread (Mechanical) · Answer 7 · 2023-07-26 15:55:41

I called a leading UK extruder and was informed this process is not one they are aware of, so my guess is this isn't possible.

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Aluminium Extrusion - Tapered Section