Spinning aluminum bottleneck

Hi all,

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I am trying to make this aluminum bottle. The body of the bottle can be deep drawn and ironing, But I don't know how the bottleneck is done. Look likes spinning is used, but how do they take the spinning mold out of the bottle when it's done?

Can somebody help me with this? some picture and video would be greatly appreciated.

Thanks, Tuan

Reply to
yvnm2tp
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The ratios there look a bit challenging, but one technique is to make the spinning form out of an assembly of pieces that will each fit through the neck. You remove one key piece and then all the others come out one by one.

Another would be to cast the form out of a low melting point metal and then melt it out when done. In that case you'd make the mold to cast the form so you could recast it for each item.

A third idea might be to spin the neck down without anything inside the tapering part, perhaps with a rod inside the neck to define that.

A fourth idea would be to have an inside tool that's moved along with the outside tool in a controlled manner, more closely approaching the shape each time. CNC spinning so to speak.

Reply to
cs_posting

You might also do the deep draw first, then hold it in a collet while spinning the neck with three rollers that slowly close and form the neck. Then perhaps only forming the threads would require a straight insert.

Reply to
Tim

Hi Tim, Thanks you very much for the advice. I saw this video on youtube today, and I think I might try this method first.

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think the last method that you mention is how Sigg make their aluminum bottle. Thanks again. I will keep you updated on the making of the bottle. Tuan

Reply to
yvnm2tp

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holy shit. awesome. cool! is that how they make oxygen tanks?! years ago i got a gingery book "metal spinning", wrote about "spinning in air" with no metal back up form. those necked aluminum bottles are pretty amazing. when they neck down aluminum cans they do it lightning fast, i suppose necking the aluminum bottles is slower but i'd assume still incredibly fast. seems they'd need to insert some sort of tool to back it up (due to the thinness of the material)(?).

b.w.

Reply to
William Wixon

Very cool, thanks for the link.

You might be able to spin your bottle with a single roller with soft aluminum, I really don't know for sure. Let us know what you find out. I would certainly be curious.

Reply to
Tim

What you're looking for is called "spinning on air" Essentially spinning without anything backing it up. I've seen guys spin candlesticks out of 28g silver. It requires a lot of skill and a light touch.

The necks on Sigg bottles are done with sequential drawing dies. I think there were 16 of them. It was on "How its made" last week

Paul K. Dickman

Reply to
Paul K. Dickman

I'm wondering if it is formed hydraulically - water as a fluid?

Reply to
N Morrison

Another video on metal spinning. Amazing huh?

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Reply to
yvnm2tp

One of the how-to shows had exactly that, making aluminum hiker's water bottles. Was a recent show, How It's Made, I believe.

One way I've seen it done is to use a segmented die and squeeze it down. The metal temper will have to be just right to get that to work, though. I think a mandrel was used to back up the work.

Stan

Reply to
stans4

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