Seeking Advice On Sheet Metal Stamping
Seeking Advice On Sheet Metal Stamping
(OP)
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
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





RE: Seeking Advice On Sheet Metal Stamping
Maybe the guys blow you off because you present like you have no idea of the costs, or because they presume you can't afford or justify it. If so, their fault, but you might do better if you play there game and dress the part when you visit.
A wild thought, is the OEM stamping die available, maybe as scrap.
I know nothing of stamping dies, but I do know something of plastics injection moulding moulds. The plastics moulds will be more complex, but would cost several tens of thousands of dollars. Just the steel would be thousands of dollars.
Regards
eng-tips, by professional engineers for professional engineers
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RE: Seeking Advice On Sheet Metal Stamping
If startup costs were in the tens of thousands, then frankly, that would be okay. A halfway decent 30 yr old OEM 911 deck lid in AL goes for about $1,000 - $1,500 each - and AL hoods or duck tails would go for much more - if anybody made them. So I'm just amazed they aren't even willing to talk to me. I can recoup tooling costs pretty quickly...even substantial tooling costs.
Oddly enough, a friend in the garment industry tells me he had a similar problem until he moved his manufacturing overseas. He said American companies were routinely dismissive and rude. But when he went to India, he got a completely different attitude. I'd rather stay domestic. But I'll go overseas if I have no other choice. I just today emailed about 20 companies in India. We'll see what they say.
As for acquiring the original dies, I believe they were bought by a US company that specializes in steel reproductions. So I am out of luck there.
RE: Seeking Advice On Sheet Metal Stamping
The same guys who were arrogant to you will be the first to complain when challenged by imports.
You will also have an export market for your product. I can fix you up with people here who know that market.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Seeking Advice On Sheet Metal Stamping
An injection molded plastic part is, allowing for shrinkage, a geometric complement of the cavity that made it, so you can make an acceptable mold for a plastic reproduction from a cast of the finished part.
Not so for metal, which has to be overbent, working it along the stress/strain curve, which just for fun is different for steel and aluminum, and for different heats of each. Stamping dies bear only a passing resemblance to the finished part geometry, and there may be more than one pair of dies involved in progressively refining the shape from flat to whatever.
Metal also presents as sheet, not meltable pellets. The dies have to draw the metal from the blank into their cavity. In the process, the metal rubs, hard, on the die surface, possibly scarring the metal and eventually wearing the die.
Wait; it gets worse. The metal often wrinkles as it's drawn, so the dies may contain odd features to control the wrinkling, or to induce it to occur in a portion of the workpiece that will later be removed.
For exammple, I think the "SME Die Design Handbook" carries a photo of an old Ford rear roof section, mid- process, with a big ugly wrinkle right in the middle of it... where a hole would later be punched for the rear window.
That book would be a good investment for you.
Mike Halloran
Pembroke Pines, FL, USA
RE: Seeking Advice On Sheet Metal Stamping
As with any new expensive project many shops will be wary of spending a lot of time quoting a project like this. If you find a few places with actual capabilities and ask for a ball park range after supplying a digitized model and what they need as a down payment to get started you will be better received.
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Seeking Advice On Sheet Metal Stamping
Aston Martin or Lotus would be the obvious people with expertise with low volume tooling. I think for aluminium you could use a soft form tool, in which the male part is a rubber block. I don't know what the quality would be like.
To be honest I think you are barking up the wrong tree, steel dies are designed for 20000 parts (or more) per annum, and need enormous presses.
Howver, if you /do/ find a method that works there are a lot of car companies that would be interested, prototyping is a lucrative if challenging business.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
PATPRIMMER WROTE: The same guys who were arrogant to you will be the first to complain when challenged by imports.
Funny you should mention this because I got the following email today...I don't think I have ever called a client a "crybaby" at any point in my entire career...I replied to him saying he had done me the favor of removing his company from my list of prospects...
And to establish the context, he is correct that I didn't include size measurements - however I did include a PHOTOGRAPH of the part in question clearly showing the size...
Amazing...will I need to beg US metal working companies to even talk to me?
-Janus Cole
--- On Sat, 7/5/08, John Baker wrote:
From: John Baker
Subject: RE: Contact Us Form for General A&E
To: JanusCole
Date: Saturday, July 5, 2008, 4:44 PM
Don't be a cry baby.
Consider other alternatives. You haven't even said how big the lids are. If they're bigger than a foot in either direction then of course tooling would be prohibitive. You should look at other ways of manufacturing it that specialize in larger items. Why not consider hyroforming or vacuum forming. Cheaper tooling, slightly higher unit price. The Internet should make your work easy.
RE: Seeking Advice On Sheet Metal Stamping
Hydroforming is an interesting suggestion - I haven't seen it suggested for a body panel.
What sort of quantites were you thinking of?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
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.
Mike Halloran
Pembroke Pines, FL, USA
RE: Seeking Advice On Sheet Metal Stamping
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
Thanks,
-Janus Cole
RE: Seeking Advice On Sheet Metal Stamping
Vacuum forming, or possibly something like it (with a little more pressure from the open side of the mold, perhaps) might be what some people really mean. Vacuum forming as I know it is used for thermoplastic parts. You take a thermoplastic flat sheet, heat it up uniformly so that it is soft but not melted, place it over a mold that has many openings to allow vacuum to be applied underneath it, and suck the sheet into the shape of the mold. It's limited to parts for which a flat sheet can seal against the outside of the mold - otherwise, the vacuum just leaks in from around the edges. Of course, if this is not convenient for the finished part, it's possible to make the part bigger than necessary so that it *does* satisfy this limitation, then trim it to suit. I've never seen this done with metal, but that doesn't mean it's impossible. Controlling wrinkles could be an interesting challenge. With softened thermoplastic, this is not a problem.
RE: Seeking Advice On Sheet Metal Stamping
However those are all for tubular constructions more than external panels, hence my question to Mike.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
Free-form hydroforming is also possible, as in welding up the edges of two suitably pre-shaped blanks, and inflating two boat hulls, just by pumping oil into the space between the blanks. Essentially no tooling cost, but limited control over the finished article shape.
I was thinking in terms of a traditional blanket type hydroforming press, except without the press, and doubled up with two blankets and two workpieces sandwiched between two platens with simple tools affixed.
Mike Halloran
Pembroke Pines, FL, USA
RE: Seeking Advice On Sheet Metal Stamping
the biggest benefit I see is the need for only one Die.
RE: Seeking Advice On Sheet Metal Stamping
Have you tried talking to prototype sheet houses out of detroit? Business is kinda slow here, most places seem to need some work.
http://ww
I can honestly say that I've been to these three: Matrix, Oakley, and Quasar, seemed like good shops.
Nick
RE: Seeking Advice On Sheet Metal Stamping
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Seeking Advice On Sheet Metal Stamping
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Seeking Advice On Sheet Metal Stamping
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!
RE: Seeking Advice On Sheet Metal Stamping
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Seeking Advice On Sheet Metal Stamping
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Seeking Advice On Sheet Metal Stamping
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://
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
RE: Seeking Advice On Sheet Metal Stamping
Mike Halloran
Pembroke Pines, FL, USA
RE: Seeking Advice On Sheet Metal Stamping
RE: Seeking Advice On Sheet Metal Stamping
RE: Seeking Advice On Sheet Metal Stamping
RE: Seeking Advice On Sheet Metal Stamping
We have dealt with these people on a few occasions and I would highly recommend them, well worth speaking to.
http:/
RE: Seeking Advice On Sheet Metal Stamping
good luck, Janus.
Griffy