Seeking Advice On Sheet Metal Stamping 1

[JanusCole]

Hello,

I produce rear end deck lids for Porsche 911's in my basement workshop using traditional hammer forming techniques. I do them in aluminum since OEM parts in aluminum are NLA and so owners are willing to pay a premium. That said, each part takes a lot of time and may ability to add new parts to my product line is extremely limited (it can take months to build a proper hammer form). So I'd like to have the parts stamped in aluminum instead. Now to be perfectly honest, deck lids aren't incredibly complicated parts (see attached picture). There is a top exterior piece and a bottom structural piece and that is pretty much it. No complicated features or curves. And yet, I have approached a couple of shops that claim to do metal stamping and they all say that the tooling would be prohibitively expensive and difficult. Of course, they won't give me any ball park figures or explain why it would be so difficult. So I am baffled.

Now, I am accustomed to doing this stuff by hand in my workshop. So I know little about having manufacturing done for me. Can anyone give me some advice or point me to a place where I can learn how this is all done? I assumed I'd just have someone scan the top and bottom sides with a laser scanner into a CAD file and then I'd pay someone to cut a die. Then, presumably, I'd just have someone else do the stamping in aluminum. What am I missing here? Can anyone give me a ball park figure of what it might cost? I am encountering roadblocks at every turn and it is very frustrating.

Thanks,

-Janus Cole

 

[NickE]

I've seen (Techrepped) DDQIF steel hit with kiksite dies to create A1 prototype panels, but I've only walked by real PPAP'ed (or whatever the OEM internal quality requirements are) stamping operations.

So I dont know Greg, seems to me that you still would need to do a FLD and "massage" the die (any process is going to need that anyway), but yes a simple stamping operation would do it.

Nick
I love materials science!

 

[GregLocock]

Thanks. Is the OP still reading? Are we on the right track?

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[patprimmer]

He has only ever posted in this thread, and he logged on today, so I guess he is still checking in.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[JanusCole]

Greg Locock wrote:Thanks. Is the OP still reading? Are we on the right track?

Yes, I am still checking in. I was just keeping quiet because I am being a fly on the wall and you guys know tons more than I do. I've also been waiting for the various companies I've contacted to reply to me. And responses have trickled in slowly. So I didn't really have anything useful to offer except to keep saying, "That's interesting."

Most of the responses I've gotten have told me that they don't have the tonnage/tooling required to stamp parts in the size I am making - about 120 cm x 90 cm. And that's okay. It's a bummer but I understand.

That said, I've recently been emailing companies that do hydroforming. I used ThomasNet to find them. Again, most specialize in small parts. So I've no luck yet. But I haven't given up hope.

There was a thread by a guy on MetalMeet who posted pictures of some molds he was making of original Willys doors. Claims he used the molds to pour kirksite dies and then had the parts formed by a local hydroforming company. If he can do it, I am certain I can. I actually create my hammer forms by pouring a mold off of an OEM part in ultracal cement and then coating it in Devcon Plastic Steel. So I am already half way there. I can make cement tooling molds until the cows come home. However, I am unfamiliar with kirksite and with the task of finding a company to do the hydroforming. But hey, that's why I'm here.

Mike Halloran wrote: If a low production rate can be tolerated, the tooling can be relatively inexpensive, e.g. stacked plates bolted together instead of an actual press. It might be possible to do both the shell and the reinforcement in one inflation cycle.

I actually ordered this video on that very topic...

http://www.tinmantech.com/html/vid_fluid_forming_alum.php

Seems like complete madness to me! Only thing crazier (and yet way cooler) would be to use "explosions"! I was planning to leave the manufacturing to the pros. But I suppose it can't hurt to try some hydroforming experiments with small parts. If I don't post anytyhing in the next six months, you'll know I blew up the shop during a horrible "home hydroforming" experiment.

Thanks,

-Janus Cole

 

[MikeHalloran]

The beauty of using liquid for hydroforming is that _relatively_ little energy is stored in the liquid. You can still make a pretty good 'bang' when something ruptures, but you probably won't lose the roof...



Mike Halloran
Pembroke Pines, FL, USA

 

[richardbuss]

Bit late - I think the OEM tool was a mono block casting in a grade similar to P20.

 

[pressedmetalguy]

Dont know if this is a bit late,, i manufacture heritage pressed tin ciellings out of 5005 aluminum and the parts can get quite big, a non shrinking resin die will do what you need it to and be relativly inexpensive, you make a master in tooling plastic or magneesium and for a resin die from that, rubber stamps dont work because your putting uneven tension on your part causing thinning and possibly ripping, if you need to know how to get a resin die made email me and ill talk to you about my manufacturing tequniques and maybe they can be applied to you, oh by the way you will need a hydraulic press $10000 magneesium master $200 sq ft resin $1200 per 20 gallon

 

[thruthefence]

Years ago there was a homebuilt kit aircraft called a "Questair Venture", retractable gear, many compound curves,sorta looks like a flying egg. As I recall the airframe panels were hydroformed. You can't much lower production numbers then a homebuilt kit. Somebody had found a way to produce them in small numbers at a profit.

 

[ajack1]

If you want to form aluminium then super forming is the way to go, I have no idea how complicated your part is but you can achieve amazing results with this process.

We have dealt with these people on a few occasions and I would highly recommend them, well worth speaking to.

http://www.superform-aluminium.com/technical/technical-summar.html

 

[griffengm]

FWIW, During the WWII era, there were Al forming dies for aircraft skin parts made of concrete. I have no experience with these other than having read about them. IIRC, high wear areas were built in with steel inserts.
good luck, Janus.

Griffy