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200 ton hydraulic press enough for small precision closed die forging?

haptic

Plastic
Joined
Aug 8, 2018
I'm considering buying an affordable 200 ton hydraulic press for an in-house R&D cold forging project. The problem is, I have no idea if this will work.

See the image of the part. It's about 90mm x 54mm x 4mm. From the image you can see that the part is more or less just a frame, the width of which is about 6mm.

I would like to make this out of Aluminum 7075 and perhaps even titanium (am I dreaming?).

Thoughts on putting rough shape slugs (e.g. a waterjet cutout first) then closed die stamping to produce this?

I'd like to take this approach as opposed to machining because of the intricate curves etc. So if I can't get those with forging techniques, I'd opt for machining.
 
The answer is "maybe". It depends on ultimate deformation of the blank to final part, whether you're willing to have multiple, progressive dies and/or annealing between presses, the stability of the 200 ton press (just having the force isn't enough, you need rigidity, planarity and strength to allow the dies to function), and whether you or a contractor can design appropriate dies.

If final machining will still be needed, consider stress relief and distortion as a risk for the finished part.
 
...The answer is "maybe". It depends on ultimate deformation of the blank to final part, whether you're willing to have multiple, progressive dies and/or annealing between presses, the stability of the 200 ton press (just having the force isn't enough, you need rigidity, planarity and strength to allow the dies to function), and whether you or a contractor can design appropriate dies...

Yeah, a 200 ton "die press" is a different animal compared to a 200 ton "shop press". If this is your first venture into die-forming
I'd suggest that you need to do a bunch more research before getting in too deep--the more you dig the better you'll understand
the intricacies of the process...
 
I'm considering buying an affordable 200 ton hydraulic press for an in-house R&D cold forging project. The problem is, I have no idea if this will work.

See the image of the part. It's about 90mm x 54mm x 4mm. From the image you can see that the part is more or less just a frame, the width of which is about 6mm.

I would like to make this out of Aluminum 7075 and perhaps even titanium (am I dreaming?).

Thoughts on putting rough shape slugs (e.g. a waterjet cutout first) then closed die stamping to produce this?

I'd like to take this approach as opposed to machining because of the intricate curves etc. So if I can't get those with forging techniques, I'd opt for machining.

Take a look at hydroforming with calibrated explosives. There's info on the net wherein a large commercial jet airliner cockpit is done that way to tight spec. Lot of crucial detail around the window frames on a pressurized critter.

Simpler things with complex curves and unusually deep draw as well. ISTR the bum-curved stainless seats in Hong Kong's underground rail were done that way - Metro Cammell the original builder, but perhaps out of Australia?

Dunno if its "in shop" do-able. Suspect it would have to be contracted.

As to 200 tons... not my area of expertise. We had plain old crankshaft and flywheel mechanicals, 25 tonner for making clamshell stainless body-model hearing aid case a bit smaller than a pack of cigarettes. No real "detail" to those. Mostly just a rectangle with nicely rounded edges and a depression for a microphone grille. Hydraulics are very different critters. No peak "impact" if you will. Not better nor worse - just "different".

Galis had a SIX hundred ton Niles hydraulic "wheel press". Not related to your need, but the surprise when running the old T-Rex wasn't so much about what 600 tons could do, but rather what it could NOT do!

Before you buy a press? Take your dieset around to he who has more than one. Test it.
See what works. IF it works.

If it is "R&D", not production, in-house? I don't think I would want to own any press at all. I'd want to "own" a good working relationship with an expert already long years in the bizness instead.

Too expensive and time consuming to reinvent HIS wheels if yah can just hire the use of them.
 
Problem you have is there so slow, the heat gets sucked out of the work, this is actually more of a issue on smaller than bigger bits.
 
Wow thanks you guys for quick responses and great advise. This is still "R&D" and I'm struggling mostly because I want to try things out myself I think. The deeper I dig, the more I realize that relationship with an expert is probably what I'll need.

Thanks for again for the perspectives.
 
The picture would help. The reality of forging or press forming an open part can be pretty complicated. Openings pre-cut in a blank may not wind up where you expect them when the die closes. You can do a lot with a simple die. We do all sort of odd stuff using waterjet cut blanks and improvised dies, using a press brake or hydraulic press depending on the situation.

The hard part with dies is where the die actually cuts the material, whether it's blanking from a larger sheet or trimming a part as part of or after forming. You can get pretty far with simple tooling if all you need to do is form the blank, not shear or remove material.

The tonnage can be low if air forming, i.e. the die only makes contact in specific areas, and the natural inside & outside radii formed between the contact areas are consistent with the material properties and your design requirements.

If your intent is for 100% of the surface area of the part to contact the die surface and take on its exact shape, that's a different situation, much more of an engineering project, with precision tooling in hard material, and far higher tonnage.

In between those extremes, there's also a lot you can do with a stripper incorporated into a die, not sure if that's the proper term here, I'm referring to a separate initial action that clamps the perimeter of the blank so that it stays put and is not drawn into the die.

Forming flanges in or around a part, e.g. a lid, or a cup, there's a point where it becomes a drawing operation, again more of an engineering project.

The point of my reply here is the ordinary industry way to stamp, form or forge a part involves a precision die set and precision machined tooling, esp. if the intent is making thousands or millions of a part. There's plenty of books that go into great detail about the sub processes - stamping, drawing, forging etc. How your part determines what processes are required and how the choice of process influences the detailed design of your part - most likely the part, process and tooling all designed together.

But for an R&D project where the objective is to proof a design, or you only need to make 1 or 100 of something, you can be as clever as you want using improvised methods that don't appear in books, at least not books I've seen, and I've read a lot of books on this subject. I've made forming dies constructed of nothing but stacked up waterjet parts, maybe some TIG, hand filing, a machined profile here or there, and occasionally urethane die springs to add a stripper action in an otherwise single-acting press.

We also waterjet cut part blanks for another business that makes more traditional production tooling, specifically press forming pre-cut blanks, where the net shape of the blank is dialed in to where they can skip trimming the finished part. That works for certain part geometries.

Much of that prototype work gets done in a 100 ton H frame shop press, with or without a die set, depending on the need for alignment. The production work then gets done elsewhere using traditional double acting hydraulic or mechanical stamping presses.
 








 
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