How Were These Aluminum Cans Made?

[BudB]

It seems to me that back in the 70's Coors was using impact extrusion to make their cans where a punch struck a aluminium slug at high speed in the bottom of a shallow die and the material "squirted" up along the punch and the trimmed to length for the capping.

[darryl]

This impact extrusion is interesting. Can definitely see the need for a lube. Mostly I'm wondering about the pressure required. I wonder what the peak pressures are?

[plunger]

Yes its a "Cupping Operation" and also refereed to as a "Draw, Redraw" can

Rich

Okay I had the time to google it. Its called a reverse redraw when the second operation turns the pot inside out. It stress relieves it because of the material being pulled in the opposite direction.It always amazed me how the pot operators would stand in front of a massive noisy polisher for nine hours a day, some having done it for twenty years.
The toilets had a perpetual smell of marijuana wafting around .I think this is how they coped.

[old mart]

Shame that the chromed cans were for nothing more than to look pretty, such a waste of technology.

[Baz]

With impact extrusion there is no need for lubrication and the pressure is probably hard to measure because it is an impact hitting a piece of metal that doesn't give much then is suddenly molten so pressure drops to zero. Probably a good engineering degree question to work it out.

[boslab]

There are literally hundreds of steel chemistries and heat treatments for can lines, the DWI line at carnaud metal box was at 1000 cans minuite, mentally fast, dirty steel is the bane of tools, the cans get ironed to microns, sometimes the inclusions are thicker than the steel wall, it splits and messes up the tool, they don't like stopping a line, expensive, the presses work so fast you can't see them without a strobe, amazing steel can get that thin, as said clean steel is vital, big ladles (300 tons plus, aim 340) allow the alumina to float out, sometimes with the help of porus bubbling blocks with argon to lift the crap, sometimes with a rinsing lance.
Rolling it is tricky too, "coffin rounds" on the mill, start narrow out as fast as poss then gradual narrowing
The DWI is made at the middle of the sheet width reduction when the profile of the roll is just right wedge correct crown correct.
You can't as mentioned make cans from open heats, Ie unkilled, mind you can't continuously cast unkilled steel, I tried (by accident) and blew up the caster aka breakout of the slab, must have pored 80 tons into the spray chamber, Big Bang, how we got an untreated ladle is still mysterious.
We made a trial of ultra low carbon steel cans, that worked, and of calcium killed, too expensive but worked.
The last steel I had anything to do with chemistry wise was the stuff for easy open ends, that took years to get right, they made millions off licensing that grade, wish I had some of it!
Digressing as usual you could easily spin the covers you need, not so hard, I've even seen cans fabricated by tig annealed and rolled on a steel plug form with a roller bearing in the toolpost so there's options available to reproduce. The covers
Mark

[754]

That would do for the round ones....

[boslab]

You could bend up the square ones I suppose, one of those letter benders would be a good way, they aren't thick but you probably need a chill or heat sink inside to weld, copper flash and chrome or whichever way it gets done, I wonder in thin stuff if hydro forming might be the answer, well not so much hydro as grease, an ordinary grease gun can knock out 6 or 7000 psi, amazing,
A mould or die that's square is easy, just an idea
Mark

[AD5MB]

anent that video - it is good that instructional videos have gotten past the "early man in his cave" starting point. every furshlugginer video back in school, here's how the caveman solved this problem...