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form a pipe into a cone/spherical shape?

form a pipe into a cone/spherical shape?

form a pipe into a cone/spherical shape?

Hi everyone!
I am looking for a machine that can produce a tapered cone shape from a metallic pipe/tube, but I’m unsure of the actual machine and process necessary to get this result.
I can only immagine that a progressive or multidirectional press may work or possibly some kind of rolling action
Does anyone know if what I want to achieve is actually possible, and if so what machine and process would do it?
Your help with this is very much appreciated
Many thanks

RE: form a pipe into a cone/spherical shape?

Thanks for the reply and video's
The goal is to do the opposite of what they are doing on the videos, basically shrinking the tube to create a spherical cone shape which would terminate the pipe
It is on a much smaller scale - between 4mm to 15mm diameter pipe (depending) with a wall thickness of roughly 0.5mm
Quantities would be in the thousands

RE: form a pipe into a cone/spherical shape?

I don’t know of a machine but you may be able develop the end of the tube. If you visualise a cone existing on the end of the tube, cut two slots along the tube axis, at 90 degrees to each other (you may need more than two slots, but with equal rotations), from the cone top to the start of the tube. Then unfold the four leaves to be parallel to the tube. The shapes you have are what you want to develop. You could cut the end of the tube to develop and then fold / form into place. You’ll have to weld them together. Just an idea!

RE: form a pipe into a cone/spherical shape?

This would be much easier if you just made some end caps by forming them into a sheet of metal and then welding / gluing/ brazing them onto the end.

Can you daw it out?

A true hemisphere or what exactly?

A pointed end will be very stress intensive.

What are you trying to achieve?

Would a crimpled end do?
Does it need to seal so you need welding?
Is it under pressure?
How much pressure?

Can you heat the end of the tube to melting point?

As you can see there are many issues which you're not saying so far.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: form a pipe into a cone/spherical shape?

A crimped end would not work as it would need a true hemisphere to create the seal
The pipe would need to support up to 1.2 PSI and would seal within its fitting, This is not the problem as I would incorporate a joining component that would secure the pipe
If necessary, heat could be applied to create the shape
I understand there are other methods to produce a symmetrical cone shape on the end of a pipe, but I was hoping for a simpler manufacturing process which could produce the required result, be it to - press it, roll it, or a combination. I was guessing that my idea maybe ok in theory, but in reality - is beyond physically possible! (Easy to expand an already formed metallic pipe, but to reduce or shrink it is physically very different)
If need be a copper material would be considered for its malleability, but even with this - still unsure to whether a satisfactory outcome could be achieved?
If I am wrong and anyone knows of a machine or process that is capable to do this, please let me know

RE: form a pipe into a cone/spherical shape?

I don't have experience with either process, but both of these may be of interest, although I don't think either of them will be able to seal the tube end.

Metal Spinning
Tube Swaging

Also, posting a sketch of what you are trying to achieve never hurts, just so we're all on the same page.

RE: form a pipe into a cone/spherical shape?

To create a cone or spherical shape from the material at the end of the tube, I would think you have too much material required for the final shape. You are going to have to remove the excess material, leaving sufficient to form the new end shape. I would either cut, form weld and cleanup or attach an appropriate preformed end fitting.

RE: form a pipe into a cone/spherical shape?


Thanks for the vids - Metal spinning looks promising, there again, the length of the pipe could be a problem
See attached pic - very rough sketch
Doesnt matter about sealing the end as it needs a hole of around 0.5mm to 1.5mm depending (Its not a problem if too much material is gathered at the end, as this can be trimmed off or drilled out) The main objective is being able to shape the pipe)

RE: form a pipe into a cone/spherical shape?

Can you spin the tube or is this something to be done on the end of pipe?

A plug inside or outside with some glue would be far easier....

AAs you say, compressing / folding something round into a different shape is actually quite difficult as it can collapse, crumple or you just end up with too much metal or difficulty with holes in it.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: form a pipe into a cone/spherical shape?

Yes the tube/pipe needs to be one piece so it needs to spin if thats the method of being able to shape it. thinking about it, the length of it will hopefully not be a problem

RE: form a pipe into a cone/spherical shape?


A crimped end would not work as it would need a true hemisphere to create the seal

This is not true in general. Military infrared sensors use vacuum Dewars with copper evacuation tubes (~0.2" diam) that are flat-crimped off and failure rate is negligible.


TTFN (ta ta for now)
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RE: form a pipe into a cone/spherical shape?

I’m not looking for a sealed off pipe. I need the end of the pipe to be in a tapered cone shape ideally with an opening/hole at the end. I just want to know if a process, or more importantly what machine and process is able to reduce/shrink a metallic pipe in such a way?

RE: form a pipe into a cone/spherical shape?

Some form of heating to increase the malleability is usually used.

The main problem is the section area of the tube is being reduced to nearly zero from a non-zero area.

I would look at having copper slugs formed to the conical shape and brazed to the tube end. One could create a countersink in the tube end and a chamfer on the conical part to provide a self-jigging joint.

RE: form a pipe into a cone/spherical shape?

Thanks so much everyone for helping and advising with this problem!
Looking at the last couple of posts shows there are methods to produce the type of pipe end I'm looking for, I will look in more detail at the links MintJulep posted and hopefully they will provide the actual processes involved in making something on a scale I am looking to achieve

RE: form a pipe into a cone/spherical shape?

Blacksmiths have been known to do this sort of metal forming on pipe or tube ends.


RE: form a pipe into a cone/spherical shape?

Take a look at videos where they are making gas bottles. The tube is heated and then shaped using a metal spinning technique.


Around 1:13 the process of forming the spherical end is shown.


RE: form a pipe into a cone/spherical shape?

I have seen people spin form domes ends on tubes, usually either Cu, brass, or SS.
Some of these are truly sealed and others are only a shape without a seal.
High pressure oxygen bottles are made this way.

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