If you have ever looked closely at a typical mass-produced automobile, you will be familiar with pressed-steel panels. Complex curves can be repeated thousands of times over, by putting a sheet of steel between shaped tooling in a press and applying huge force. The same work that would take a skilled panel beater weeks to do by hand, in a second. It’s something [Stuff Made Here] tackled when he wanted to wear a set of Crocs in the workshop, and needed to make the tooling to produce them in his hydraulic press. The resulting video which we’ve posted below the break shows his learning curve, and along the way is a handy primer in sheet metal pressing.
We watch as he discovers the properties of sheet metal under the stress of pressing, how it wrinkles and folds, and how the tool needs careful design and the sheet needs to be securely clamped in place to prevent this. The big surprise is that his tooling is made from CNC-machined wood, while we’re sure that it would wear given repeated use it seems that the forces on the tool are not such as to destroy this material. In the end he’s produced a multi-part tool including both halves of the press tool, a machined guide for the moving part, and a set of substantial sheet metal plates to constrain the material. The steel toecap application may not be everyone’s first idea when it comes to sheet metal forming, but we’re sure this technique could find application in many other projects. It’s a territory into which we’ve edged in the past, but never with pressings this complex.
Thanks [Moritz] for the tip.
I’ve wondered for a while if it would be possible to hydroform or hydraulic form against a series of 3d printed surfaces, each set of surfaces closer to the end shape, so there would not be a lot of plastic deformation in any individual step. This is generally how cold forging is done, for the same reason: to minimize damage to the mold. It’d be pretty neat if you could form a replacement automotive door panel against a 3d scanned and printed surface.
If that process could work easily I’d be in needing parts for rebuilding old cars
Thirds toe caps could be adapted to Aussie safety boots as well
That is how progressive hot forging is done too- progressively closer to net size punches and dies. My day job.
Steel toed crocs- ok, that’s a new one!
Was thinking of doing something like this for custom steel shields for my motorcycle boots- in case I hit another deer at 45 mph with my damn leg itself.
Plus I like the Mad Max/Fist Of The NorthbStar aesthetic, so theres that, haha
Aere you intending to manufacture hundreds of the same part? Companies doing this usually just buy old factory dies and stamp original parts.
Modern car restoration is
1 photogrammetry to get the shape into cad program
2 laser cut steel sheet rib model to sanity check on a car
3 reverse of 2 for actual metal worker to make the shape by hand
no stamping
example starts at 29:00
https://www.youtube.com/watch?v=duxpltwNgHQ
as for replacement door panels, you do that by hand in 30 minutes, example 1969 Porsche 911 starts at 16:40
https://www.youtube.com/watch?v=JqpKJQlYBzE
finishing up
https://www.youtube.com/watch?v=P7xXu7ceN58
What I’m specifically interested in is being able to do things like scan an E-type hood and then form one out of aluminum, since steel ones cost about $12,000 and aluminum ones are even more. I’ve fabricated compound curvature body panels using an english wheel. It doesn’t scale well and a lot of the time you don’t realize you’ve a subtle curvature error until the paint is on. (Although 3d scanning the bare metal might be a good way to characterize curvature errors: I hadn’t thought about that until just now.)
If I was serious about it. I’d mechanically take off templates, cut them out of plywood, jig them in a frame to represent whole piece, yet removable for checking while working. If you get one of those old HP Books on custom bodywork, it’s all smaller panels held with cleckos, tag/spot welded then finish welded and welds ground down…. but still they used a lot of filler lead.
Wangle yerself a visit to the Morgan factory though…
https://www.youtube.com/watch?v=WTggLgcQBpc
plywood templates sounds tedious compared to a scan + laser cut parts
one video up/down in the playlist of that Porsche restoration I linked earlier cad technician shows off how he reconstructed rear fenders from historical photos
Looking to do the same. Could you do a male / female car buck out of plywood for each piece and then press the metal sheet between them on a hydraulic press?
That’s exactly why I’m here. At my work, we make sheet metal components for the HVAC industry. I’m “pioneering” making form dies (crush die to start) with 3D printed tools. I’m trying to find information regarding industry “rules of thumb.”
Somebody has to be doing this already. I wish I knew who. Regardless, I’m excited to be testing this concept with the company’s dollar. This “concept” seems evergreen, limitless potential.
There is some videos on using 3D prints to from sheet metal.
https://www.youtube.com/watch?v=wsxFXTKaXdI
https://www.youtube.com/watch?v=fxzqkhmcRlY
https://www.youtube.com/watch?v=4nVLj9px_tk
https://www.youtube.com/watch?v=fxzqkhmcRlY
I applaud the metalworking effort, though not really the application, since self made toe caps can turn into self made toe guillotines if you get anything slightly wrong.
I was thinking about the same thing… of course the metal forming method is impressive, but wouldn’t that small inward curve facing the ankle side act as a guillotine if something went awfully wrong? Maybe a slightly “outward” curve just for the sake of “not shoving the metal into your foot” in the case of something heavy hitting the middle?
Well, forget it… maybe “not wearing crocs at the shop” would be better. “Not wearing crocs at all” sounds even better… lol…
Anyway, I must say the technnique is awesome!
I had a loaded wooden pallet set on my steel toe one day, and the forklift driver had to pick it up before I could move my foot. The boot leather was crushed and cut along the top of the toe. Had that been my unprotected foot, the outcome would have been different.
That was without deforming the steel.
It won’t act as a guillotine under any force that would otherwise leave your unprotected foot intact, except maybe under some really unlikely combination of angles of load and forces. In every other case, you’re much more likely to appreciate the protection provided by the steel toes.
(BTW, Red Wing Boots are awesome.)
I view it as a deterrent for wearing Crocs.
And if it’s because he wants safety footwear that’s easy to get your feet out and into, well, safety Clogs is a thing that’s certified and all that.
I’ve heard this line of reasoning before, but I don’t find it very reasonable. If something is heavy enough to cause the steel to cut off the entire front half of your foot, it’s probably heavy enough to crush the bones flat if left unprotected. A severed foot can be reattached, a completely crushed foot just gets amputated by the doctor.
Hmm.. Looks like I was right: One google search, top result:
https://www.hanksclothing.com/blog/2010/07/steel-toe-boots-can-sever-or-amputate-your-toes-so-your-safer-without-them-fact-or-myt/
How does that ANSI approval work then? Just click your heels together 3 times and say “I wish these were
ANSI approved” ?
Personally I had an experience with a very worn pair, IDK if they were ANSI, but had BS and CSA ratings when new. I had got two years “hard” wear out of them, and kept them around for general “fuddling around” footwear, because they’d got as comfy as slippers. Also, I didn’t care if they got dusty/oily/muddy etc. Now, I’d say that if I knew I was going to do something that it was highly advisable/compulsory to be wearing steel toes, I would have put on my newer pair. So I’m helping the inlaws out with a rockery type deally in the garden, it was only putting soil in it and planting it, so I’m wearing these old boots. I’m standing behind it, inlaws buddy runs a barrow full of dirt up a ramp and dumps it in, one of the top concrete blocks on the back wall is loose and falls off onto my foot. Now it’s falling about 4ft, and it’s about 50lb (regular cinder block with the holes filled with cement) Not quite sure how it landed as things happened quick, but suspect it was corner down on the back inch of the toecap on my right boot. I don’t feel anything at first. Then maybe a sensation of squeezing, then I try to bend my foot and it digs right in, owww, the toecap is bent and/or rotated down onto my foot. Didn’t break the skin, but it’s tight enough my toes are starting to throb from the blood cutoff and it takes a couple of minutes wriggling and jiggling to get my foot out of it. Anyway, 40-50lb dropping 4 feet doesn’t seem like it ought to be enough force to do that, even concentrated at a point. It would give you a damn sore foot landing on a leather boot though. So that gave me an appreciation for having up to date certified good condition safety boots (Having had many much heavier things bounce off them in the past) and an appreciation that things can go wrong if they were not up to snuff.
Something doesn’t have to be approved by the ANSI group to be up to snuff.
Nice story, but it’s anecdotal and maybe your toes were rusted out.
Yes they probably were, that’s the point, not up to standard.
Crocs? Tarsels.
You lost me at “Crocs.”
Dies? We dont need no stinking DIES! https://youtu.be/Wl5_wUVxRvw?t=52
We just need a couple of REALLY rigid deltas!
That is actually pretty awesome. I wonder if anyone could home-game this.
In a way, yes: jewelers do something called sink forming, where you take several sheets of plywood, bolt them all together, then saw/chisel out a female shape in the bottom of the stack. You put a sheet of metal in the stack, drill bolt holes through it, bolt the whole works together and crank it down, then you do the same thing this robot is doing only using a hemispherical-nosed oak dowel and a hammer. You work your way around the periphery, unbolt everything, anneal it, bolt it back up, then do another round adjacent to the last round, and keep doing that until you have the shape you want. It’s hard to get a precise surface finish but you can do an excellent job of making a complex curved convex object.
I’d always thought Dutch wooden clogs the original safety shoes ‘toe tectors’?
Maybe I’m just summising, still sure they’d work better than Crocs + pressed plate??
Just 2¢
Clogs may be the safest place to have your toes, but if you move at any speed your environment is at serious risk :)
I wear wooden shoes in my shop. They’re easy to slip on and they encourage me to keep my shop floor sweeped as every screw or nail is a bit annoying to have underfoot.
Nope, it’s not surprising that wood can be used for this. It might have been a month ago. After seeing the article about 3d printed metal brakes dies it’s pretty easy to believe that wood can do this, at least for hobbyist production quantities.
Crocs are still a thing? Now that’s the part that had me surprised!
About the backboard. Just how precise does the curve have to be for it to work? I ask because that shape looks an awful lot like some snow shovels I have used. Maybe there’s an easy way for us all to get our hands on them after all.
That’s some really interesting engineering video. As [smellsofbikes] mentioned, I wonder if it’d work better (e.g., reduce the creasing, reduce the chance of the wooden mold splitting) if it’s done in several steps rather that in one big bang since the desired final shape is quite curved. Or, if it’s to be done in one step, if the stock metal is heated up first? May be not to red hot, but hot enough to take a shape easier?
Anyway, it’s very interesting to see the iterations and evolution of the mold and process.