10,000-ton steel press - looking for reference articles

[moefeaux]

Greetings,

I am a fairly new graduate in charge of designing/procuring tooling for a 10,000-ton cold-form steel press (Yes, I know that is big!) to press heads for large pressure vessels.

I am being pushed by management to run the press at the absolute lower limit of it's stroke (within one inch of cylinder rock bottom). In the opinion of myself and the other engineer on the project, this is a horrible idea for any number of reasons.

Are there any publications or online references detailing recommended operational procedures for a press that I can reference when making my recommendations? Changes to the current tooling design are being resisted at every step, and yet I am being rushed to complete this project quickly.

I just do not want to see one of my first projects as a 'real' engineer fail because I was not permitted to do it correctly.

Thanks

 

[DAVIDSTECKER]

Look in Google for "Tank Ends".
I ran across this site a couple of weeks age too,

http://www.bluevalley.com/

 

[TVP]

moefeaux,

What company manufactured the press that you are using? If it is one of the companies that is still around (many have gone out of business), they should be able to provide some technical assistance. In terms of reference materials, Metal Forming Handbook from Schuler is excellent. I highly recommend it. Use the following link for more information:

http://www.springer.com/sgw/cda/frontpage/0,11855,4-40109-22-1473264-0,00.html

 

[moefeaux]

David, actually I did need to find a circle cutter to purchase for our pressroom, so that was a great help.

TVP, Siempelkamp manufactured the press in 1982. They're still around, but they have been reluctant to give much assistance on the engineering, because we bought it used, shipped it from Croatia in pieces, modified it, and re-installed it. (Can you blame them for not wanting to get mixed up in that?) They've offered to supply parts if I need them, but not much else.

I'll try to pick up a copy of that book.

Thanks

 

[unclesyd]

Here is an outfit that does work both on the presses and controls for same. I’m not familiar with the forging press aspect but they do an excellent job on hydraulics and controls.
They also may be familiar with you press as they are also in Europe.

http://www.wepuko.com/wpe-forging.html

 

[Pressed]

10,000 ton is not big for a hydraulic press. Do you have all the info that originally shipped with that press, no-matter who sold/bought it or what changes were made, you need those papers, for many different reasons. Maybe these documents are already in your plant and you have not been informed that they exist?

Have you heard of "air over hydraulic"? Where the majority of the stroke is air, fast and at low pressure, then at the bottom of the stroke the hydraulics kick-in bringing high pressure. You probably have something similar, someone may call it "hydraulic over hydraulic" but "speed adjustable stroke" seems more appropriate. That is not a standard hydraulic press. It is a new trend to increase ppm. There are many different options available on hydraulic presses, not all are basic pressurized cylinders.

Unless your management can give you the details you will not be sure of what you have until you get the press documentation. Siempelkamp should be able to tell you the ram position of increased pressure on the telephone to speed things up, if that is in fact what you have.

But if it is a regular hydraulic press, some people believe forming at the bottom of stroke is better for a number of reasons, whether true or not is another discussion. Maybe your management will tell you more details? Post details of what you find and I will help if I can.

_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[ornerynorsk]

What's the problem if you're not bottoming out the cylinder with every stroke?

 

[moefeaux]

Pressed: Let me clarify. It's a press capable of pressing 10,000 tons of force onto unheated steel of up to 1 inch thick. It's got 8 cylinders over 3 feet in diameter, with hydraulic pressure over 5,000 psi. It's the biggest cold-forming steel press in the world we're told (tied with 2 others actually, of the same make and model). The dead weight of the press is well over two million pounds. This press: (

http://www.equipbrokers.com/8000-Ton-SMK-2.jpg

) is about 1/4 the physical size of ours. There is no air in our lines, it's 100% hydraulic, with a 12,000 gallon main reservoir and a 5000 gallon backup. "Press experts" have walked into our building, looked upwards 60 feet to the top and downwards 40 feet to the foundation and have simply said "Whoa....that's big".

Ornerynorsk: The problem is that with the current tooling design we WOULD be bottoming out the cylinder, which is why I'm trying to find the most efficient pressing location.

Thanks for the help so far

 

[moefeaux]

P.S. No we do not have the documentation. We have scanned PDF images of about half of the German engineering drawings, and some specs that were given us to the vendor.

The previous owner was the Soviet government, it was used to press tank and submarine heads during the cold war. Needless to say, nobody was very forthcoming with information, other than that they just wanted to get the world's biggest paperweight out of Croatia as soon as possible.

 

[Pressed]

A press doesn't know if the metal is hot or cold. That tonnage isn't the biggest in the world, I looked at Siempelkamp's line of presses in the 7,000 to 12,000 ton range and they were kinda small actually. You have mis-understood my entire first reply. Good luck.


_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[moefeaux]

Changing the subject, this was our press before disassembly in croatia.

http://www.duro-dakovic.com/ddip/SPS3.JPG

 

[BillPSU]

Why does the management want to run the press so close to the end of stroke? Is it the stroke length limitation or is it that they just don't want to purchase a spacer plate to raise the tooling? The best you can do is to explain your concern and warn them of the consequences but if they decide to do it anyway LET THEM. You do not own the machine and you have reported your concerns and management has decided to ignore them. You've done your job.

 

[unclesyd]

Here is something I remember discussing many years ago after reading about a fatal accident due to cylinder failure on a large hydraulic press. The press was operating at the max hydraulic pressure near max stroke and as I recall there was a discussion of “press stretch” entering into the equation as part of the failure mode. Unfortunately I’m the only one left of that group.

From your picture it looks like the original operation was as a closed die hot press. Looking at the height of the cribbing under the platen and I’m seeing what I’m thinking I can see why they want to operate at the bottom of the stroke to save from having to raise the die or minimize problems manipulating the work piece.

Here is a 10,000 ton open die in operation. This company is owned by Whemco show below.
They claim to be the largest open die forge in the US. This press was out of service a couple of years age due to a fire.

http://www.lhforge.com/lh_home.htm

These people bought the Mesta Machine works and own Lehigh Forge

http://www.whemco.com/wgoc_home.htm

The Mesta press.

http://www.asme.org/history/brochures/h071.pdf

 

[moefeaux]

BillPSU, the answer to your question is political, I'm afraid I can't go into much more detail than that. The initial engineering of the tooling was done 1,500 miles away from the press, and when we physically measured it, we found that the designs were based off of misleading stroke specs provided by the vendor that sold us the press. So I am trying to find a solution without deviating from that initial design too much, as asked.

You hit the nail on the head though, which is why I came here for info. If I am going to be required to design the tooling so that the press operates near bottom-out point, I am going to have to share my concerns in some manner.

Unclesyd: That was very helpful...I will see if I can find any more info on 'press stretch'. Maybe that could give me some hard info to work with.

Yes the press was originally used as a hot press. Due to stricter tolerancing in our heads, we require the steel to be pressed cold. We do have tentative future plans to add a furnace at some point down the road, for other types of stamped parts.

Also, yes the main concern was due to material handling. With the dies installed, it will be a tight squeeze.