Hydraulic power press design

I'm investigating building a powered hydraulic press for draw die work. The press would be used for tryout only, meaning no production.
I could easily imagine the press being hit less than a thousand times over its entire life.
Capacity would be 50-100 ton
Front-to-back working would be about 12" Left-to-right working would be 18" Stroke would be 10" Closed daylight would be about 10-15"
I was considering just using three major plates: the bolster, the ram, and the crown (on which the cylinder is mounted), and using four tie- rods to keep everything together.
My questions refer to the size of plates, and the size of tie-rods/ guide-rods.
As I understand, hydraulic presses aren't really capable of creating severe overload conditions (in contrast to mechanical presses). So, what would be an appropriate safety factor for the tie-rods? 2:1? 4:1? If the tie-rods were 4140, a single 1-1/2" rod should be able to withstand the press's entire capacity.
I have no idea how to calculate the required thickness of the three plates, to withstand the load without severely deforming. The die shoes used would always pretty much consume the entire working area of the press. While the loading wouldn't necessarily be balanced (due to the type of die work), there won't be any pin-point loading on the bolster or ram. Bolster to ram parallelism is actually quite important in this application, although the die shoes will assist in resisting deformation, in addition to the bolster.
While the die shoes will have their own guidance (pins and bushings), the ram should be guided as well to assist in preventing severely unbalanced dies from deforming under maximum loads (remember - this is tryout... Things happen). I'm not sure if it would be a good idea to have the tie-rods act also as guide-rods, or if they should be independent. They seem to be the same thing on commercial presses...
Any thoughts are welcome. I want to build instead of buy because gap- frame and 4-post presses of this capacity seem to be much larger (FB/ LR) than I need, and I don't want to have to deal with a 7500lb monster if it's not required.
Regards,
Robin
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Yer off into whacko-lands, kiddo...
Basic hyd.
PSI
HTH...
--




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Hydraulic presses are frequently custom built for specific applications. The hydraulics involved (brand new) would be about $2k, including valves, cylinder and power pack. Another $3-500 for automation, and then the steel and bronze. New press (used presses can be in *really* bad shape, while still going up and down on the factory floor), correctly sized, exactly what I want...

I'm not worried about creating the force, I'm worried about dealing with the force. I'm really just looking for safety factor info (tie- rods) and deflection (bolster).
Anyone?
Regards,
Robin
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Robin S. wrote:

Don't piece this out Robin. What are you trying to do? Here, let me help you out. "I am in the process of building a company to do________" I still think my advice earlier was spot on.
--

John R. Carroll
Machining Solution Software, Inc.
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Die building. Build only, not production. I need this press for tryout work. Perhaps I should start phoning used machinery dealers. I just assumed used presses would be fairly expensive. Perhaps I should actually check that before getting into something that's more work than it's worth (duh).

Well, I certainly see where you're coming from. However, that's not what I'm worried about at this stage of my life. Right now I'm interested in a press and a CNC machine.
Regards,
Robin
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Robin S. wrote:

Call Brett Blanchard at Artisan. They are in Livonia, Michigan.

It was a personal comment based on experience and I would not have offered it had I not given a shit. One dumb fuck to another if you know what I mean.
Robin, You won't be and wouldn't want to be the next Magna. Take my word for it. Been there, done that. Ever heard of Starboard Industries or Chivas Products?
I'd trade that history for a family.
--

John R. Carroll
Machining Solution Software, Inc.
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You'd have to tell me why first. No web address as far as I can tell...

Fair enough. I don't have a family right now, not even one on the horizon. When I'm young, right?
I'm not saying you're wrong. But I think this is right at this point in my life.

I looked them up briefly (tonight's busy). I'm not apart of Magna any more. Not really trying to be the next one. This is just something I've been wanting to do for several years now. Because of timing, I finally have the option of doing it...

Certainly a lesson I'll need to learn myself. But I'll keep your advice in mind. I didn't wake up last week suddenly wanting a machine shop. Again, years of thought. Perhaps not enough thought about the nitty-gritty details, but I think the dream has to come first. Things like money are incidental ;-)
Regards,
Robin
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Robin S. wrote:

They designed and make what you are looking for. Brett's father, Jack, is probably dead by now but Brett will know who I am and help you out. You could do worse. IIRC, the company is Artisan Mold. Hell, given conditions, they might not be in business today.
The original company, and where I worked while getting an engineering degree at that University of Michigan, was Acumen Corporation.

Your decision. My mistake is worth considering but my opinion isn't really worth a thing.

I guess my thoughts can be boiled down to good luck, God bless, and be patient.
--

John R. Carroll
Machining Solution Software, Inc.
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My major concern is shipping. I like the idea of building partly because the press would be compact, and it would arrive in pieces.

I'll keep them in mind when I'm closer to buying.

One can always walk away.

Well, it's already consume massive thought resources, so I guess I'm partially there. Next is time and money...
I appreciate the time you've taken to respond to my comments, as well as everyone else's time. It has been truly helpful.
Regards,
Robin
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"Robin S." wrote:

Robin:          Just curious, you say you're not part of Magna anymore. Was that your die grinding job? If so, what happened?     In the past you said you might be taking some engineering courses. What happened to that idea?
--
BottleBob
http://home.earthlink.net/~bottlbob
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Bob,
I can't go into specifics, but leaving was an overall positive experience. I can't say I miss the work. It's nice to come home not looking like a coal miner...
It is my intent to go to university in September 2008. I need to pick up some high-school credits in order to apply, so I'll be doing that between now and January 2008.
I guess it's my intent to get this stuff rolling over the next year and a half. I have friends who will be working with me on the project. School only runs 8 of 12 months, so there will be time (ha!) while I'm in school, but I don't think I'd be getting my hands too dirty during the school year.
Regards,
Robin
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This web site has a really neat utility called Beam Boy. Use it too calculate loads and deflection and other stuff. Don't know if it will solve the current problem, but it's pretty useful.
Later,
Charlie
http://www.geocities.com/richgetze /
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Press loading in the vertical diection is not a big deal. You will have a huge issue keeping the die set plates both parallel and aligned without resorting to the massive frame of a standard press frame. Off center loading of any progressive die will overwhelm the ability of the die pins to keep it square.
Robin S. wrote:

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He wasnt even asking about progressive dies.
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As a panel die maker, I'm aware of the dynamics of press work. I'm looking specifically for some guide to help me decide on the size of the press bolster. Certain types of die-making do not allow for balanced loading. I'm not doing progressive die work anyway.
It sounds like looking at examples of presses on the internet is likely the best method for deciding on a bolster thickness. I'm assuming I won't know exactly what the bolster is doing until I assemble the thing and go after it with a dial indicator.
Regards,
Robin
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snipped-for-privacy@hotmail.com says...

There are some examples here that may be helpful. I just priced a couple 30T presses from Tox with a work envelope similar to what you're talking about. It looks like you need to download the .pdf catalog to see the larger presses.
http://www.tox-us.com/products-presses-MA.htm
Ned Simmons
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Ned,
This is *exactly* what I had in mind. Looks like 3" plate is a good plan. Thanks a ton for the link. Perfect - really.
Do you mind if I ask you what they're worth? My e-mail works, if you'd prefer...
Excellent.
Regards,
Robin
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snipped-for-privacy@hotmail.com says...

I'm glad it was helpful. I was quoted about US $9700 for the MA30 press w/ram, about $12,000 for the MAG30, not including the actuator. I'm sure Danly or another die set builder could do it for considerably less.
The Tox actuator I spec'd is another $6000. It's perfect for the app I'm working on; fast advance at low pressure, short working stroke, fast return. http://www.tox-us.com/products_powerpackage.htm
Ned Simmons
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I'm not very interested in how thick to make the bolster or how big to make the the guide pins/press posts. I want to see how you plan to take the torque loads. Visualize a 100 ton ram coming down on a load 12" off set from the center of the ram. That 200,000 pound-foot load has to be absorded by the pins/posts without bending or siezing.
The problem with home brew presses is that they do not usually have the necessary rigidity to take the to torque loads generated with off center loading. That torque will apply a bending load to the die set pins and/or press frame, tends to jam things up. I've had to deal with the screaming when an operator raised the ram in a 150 ton hydraulic press, one pin seized, next cyle brought the top half of the die down at about 10 degrees off of flat. VERY NASTY results.
I've also had to live through the company founder wanting to build a 100 ton horizontal press using multiple rams. Spent a bundle of time and money, never did get it to maintain parallel ram/bolster orienation.
Robin S. wrote:

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You're very right. The idea is to make the upper die hit the lower interference, and actually stop (instead of flexing). It's important to do preliminary tryout at low tonnage...
I've seen presses where the bushings on the ram have been extended up (at least 2x the rod diameter, perhaps 4x) in order to reduce the rotation. It would be a major gamble to not give the ram the support it requires.
On the other hand, in the types of dies I want to build, the maximum side to side deviation would be no more than one material thickness over the the length of the die - that is, at maximum tonnage. Spotting is *never* performed at high tonnage levels until the die is close to being fully spotted (gives *very* false readings anyway). Obviously, the toolmaker's good judgement would be important.
There is also a very real possibility of monitoring the out-of-square condition of the ram using perhaps simple micro-switches in order to prevent severe damage.

For sure. In the type of work I want to do, there will be reasonably well distributed loads. It's more that the balance won't be perfect.

Well, the truth is that having a press which is incapable of maintaining parallelism is a great way to never obtain a repeatable part, and I very much appreciate the importance of this.
It looks like the presses Ned was referring to are made for very balanced loading. Although it brings up the question, how off-center do the real press manufacturers allow? On the new 2000T Mller- Weingarten at my old place, we had issues when the out-of-square parameters were set too tight. The press kept tripping out halfway through the working stroke - so they adjusted the alarm parameters....
Regards,
Robin
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