Press Forming Aluminum

I have a part that I make quite a few of. It is about 12" round with a 1" flange 3003 Aluminum 16Gauge. Which makes it some what of a headache to form manually. Up to this point I form the flange with a bead roller, shrink-stretch, air hammer then sand. I have been wanting to simplify this process for awhile as well as speed it up. So here was my first attempt.

I ventured down the press forming rabbit hole. I modeled up then machined a simple punch and die out of oak to test. Added 1/2" steel plates top and bottom for reinforcement. I had somewhat good results for a first try. Although not perfect, not a scrapped part. I do however want to improve the part out of the press if possible. I'm completely new to press forming so if anyone could point me in the right direction. I greatly appreciate any experience anyone is willing to share. I will post pics below of my results.

I Just read where annealing the aluminum could help. Would it prevent the wrinkling altogether since there is so much shrinking and stretching going on for a 90deg flange?

Hi AAR - annealing will reduce the press loads but not wrinkling. It could make the wrinkling worse depends on a few things. The shrinkage in the flange is the same no matter what you do unless you use a double acting press. The fastest way to make this would be to metal spin it then cut the flat off. If you have a lathe you could make the timber buck and a timber former and have a go. Do some research on spinning. Peter

As I understand the process, if you want the flange to stay flat, you need to clamp it really firmly between two plates before pressing on the middle. Press-forming works best with soft aluminum; some grades come that way, others are heat-treated for stiffness and would need to be annealed.

Hi Andrew - The stiffness of metals is not dependent on its heat treatment condition. Aluminium whether annealed or very hard worked and aged, its all ~70GPa modulus. Heat treat does affect its strength and elongation however. Aluminium is much more difficult to form as it has a hexagonal grain structure. Steel has a cubic structure which means it has lots of straight planes it can slip along, its like lego without the lugs. For aluminium to slip it has to climb up and down the ridges of the hexs which lock up the slippage. The easiest way to form aluminium is to use "incremental" methods like hammer forming (like a traditional panel beater would do, or now you use machines see video) and spinning. Press forming stretches large volumes of metal leading to tearing or wrinkles on compression areas. Incremental forming moves a small amount of material at a time and uses the unformed surrounds for support..... Peter

https://youtu.be/0O0DgZ5RrAg

https://www.kikukawa.com/en/technolo...ental-forming/

Thanks pete, I did look into spinning before trying the press. I do have a lathe but it's a little to small for this part. My lathe is only good for 12" and this parts flat pattern is 14". I have a spindle laying around. I could possibly throw something together so I could spin this part if the press forming doesn't work out.

awerby, So if I go this route would I need a blank that would allow for trimming after the pressing process? The parts dimensions now allow for 1/4" of trimming after forming.

For clamping the part in place, what kind of force would need to be applied? Could I use wood for all of this or should I use metal?

Hi ARR - If you want a part with no wrinkling you will need to use a double acting press or a serious bolster clamp. The metal has to be kept in tension at all times and the edges have to be "ironed" to remove the wrinkles. This is achieved by clamping the sheet edge with a ring clamp or a double acting press tool. So as the part is pushed into the cavity the sheet edges are restrained so the sheet stays in tension. It would also be advantageous for the blank to be circular if an edge clamp is used. In a double acting press there would be a circular ridge in the tool that trapped the sheet when the clamp press comes down (or up) The tool itself will have a neat or slightly undersize perimeter so as the metal goes down the sides it is ironed flat. You've done well with your timber tool, did you lubricate it? Perhaps if you make it a full circle vs what you have you may have more success as it will be better constrained? Peter

perimeter = PI*D say 3x12" = 36" at the part edge and 3x14"= 42" at the trim line so you have to get rid of 6" of material in the stretch. Since metal is incompressible thats quite a bit to get rid of as you have found out. 36/42=0.86 so your sheet at 16g or 1.6mm has to stretch `1.6x0.86=1.38mm so the tool would be made at 1.4mm gap for the ironing... then you have to clamp the edges to maintain the tension... I expect there should be no slip in the clamp...I think spinning is the go. Peter

https://youtu.be/W7QB0-AlwtI

because spinning is incremental it defies the usual rules of deep of draws etc...to make the cup in this video using a press would nearly be impossible , I expect it would be impossible but I generally don't like saying something is impossible. For instance you could do it using super plastic forming techniques

Superplastic forming - Wikipedia

https://youtu.be/KPFAoLmJ5og

The forming issues with aluminum is the reason it has not taken over steel in the auto industry. Modern car panels require very funky shapes that cannot be achieved with aluminium using conventional press techniques, so they have stayed with steel then moved to moulded plastics now they can get any shape they want in composites as this is not a forming process but an additive process

I used to run a 9m long spinning machine that tapered aluminium masts and flag poles. over 35 years ago I think...https://goldspar.com.au/about/

Peter

Maybe hydroforming - do some research on that, use a water gurney pump but spinning is the fast solution....

Here's an article on a press formed aluminium bike frame I was involved in. It was formed on an 600T automotive double acting press. That was a very big mission to get the metal to play with us... Then welding was another story...

https://www.bicycles.net.au/forums/v...ic.php?t=84059 its a very average paint job...but he does fix that.

No pete I didn't lubricate it and I should have. Using a timber tool should I use wax? I think I'm going to take your guys advice and try a double acting press tool to see if I get better results. If not a lathe large enough will be next.

Spinning the part was going to be my first attempt at making this part until I realized I wasn't able to turn it on my metal lathe. I then had plans of building a wood lathe since the cost of some to accommodate my needs are a bit much. I have the material on hand, as well as the machine capability to build one like this https://www.thewoodturningstore.com/...-1-5-hp-motor/
or even one with a bed made of 1/4" plate bent to the profile needed. Which might be the quicker way of building one. The 1/4" bed wouldn't be nearly as strong as one built from pipe like the one above. Whatever I build would be solely for this purpose. Which would you recommend?

The only reason I didn't build a lathe first is I wasn't sure on my chances of success turning it. If I happened to fail at simplifying this process I wanted it to be as cheaply as I could. Which is why I went the press route. There was nothing to build except tooling. Everything I read when researching different ways to form metal people turned thinner gauge material. I couldn't find much on 20gauge and up.

Thanks again for taking the time to share your experience and knowledge.

Hi AAR - I think the best shot is spinning. Next is to remake the tool so its a full circle. If you clamp the blank edges your press maybe not strong enough to draw the material down into the die. If you make the gap really tight and use grease or a heavy wax you may get close. Another thought is elastomeric forming but you need a heavy press for that. Its incremental as well. Peter

Elastoforming 101 | Macrodyne (macrodynepress.com

I ran across elastomeric when looking into hydro forming. I think your right though, for a part this size a 20t-40ton press would struggle.

I have never formed metal by turning it. Does it take a lot of force to manipulate 16gauge material? in this case aluminum. Do you think a lathe that size it adequate? If so I will go ahead and get started on it this week.

Hi AAR - most spinners are using 1100-0 or you can anneal your sheet with an oxy. Someone said give me a big enough lever and I can move the Earth. Most spinners also use a scissor lever which means the leverage is increased many times and the reactions are born by the machine not you... Peter

https://youtu.be/79ubwnD4eTA

Hello,

Impressive effort on your first attempt at press forming! It's great to see your determination to simplify and speed up the process. Annealing the aluminum could indeed help with reducing wrinkles, as it can make the material more malleable and less prone to cracking during forming. It might be worth giving it a try and see how it affects your results.

Additionally, you might want to explore different die designs and techniques for press forming to further improve your parts. Experimentation and learning from others in the field can be valuable in refining your process. Keep sharing your progress and results – the community might provide valuable insights and tips. Best of luck with your press forming endeavors!
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