Hydraulic Information; Presses etc.

E

Ed Schempp

Joined
Oct 10, 2003
Messages
395
I'm not a hydraulic expert; but I have been through many in my 35 years of farming. I want to share some basic information about hydraulic design for presses, rolling mills, really anything hydraulic.

The power source is the starting point, electric or internal combustion.

Roughly you need Two HP Gas to One HP Electric.

How many AMPs do you have available/ You can by with a 50 AMP breaker on a ten HP load if you split the start-up with 2, 5 HP motors.

Using 10 HP Electric you can push 8 GPM at pressure, for this example at 2000 psi. Your pump must be balanced to the motor for efficiency. If you have a power limitation you might have to consider a more expensive two stage pump. Your free travel speed is often times about 4X the working speed. You can run a 16GPM two stage if the second stage is 4GPM or less on a 5 HP electric. You get .8 GMP for every HP.

Some quick numbers; A 5 inch cylinder has a moving face on the piston that is 2.5 squared times pi. equals 19.6 sq in. A 6 inch cylinder has a face area of 28.3 sq in. 2000 psi is a ton. A 5 inch cylinder at 2000 gives you 19.6 tons. A 6" cylinder at 2000 psi gives you 28.3 tons. The larger the cylinder rod the more stable and more durable. The area or the face of the rod must be deducted from the area of the cylinder to calculate the pull pressure.

A GPM is about 230 cubic inches per min. About 4 cu in per second. You need About 4.5 GPM to move a 5 inch cylinder an inch a second.

Surplus Center catalog has about a 1/2 a page that is dedicated to hydraulic design, it is very good information.

In Press design consider a push up or a pull down, either one is much shorter than the top heavy push down designs. This allows for more stroke and higher die location. To do good forging you will often need to have your eyes at die level, for me it is easier to lift the billets a foot or so higher once than to stay bent over. I work billets in the 10-25 pound range. The longer the mechanical engagement or slides in comparison to the width the better the mechanical accuracy of opperation. H Frames are more accurate with the least amount of steel in the construction. I like a four post frame that can stabilize die travel on two axis.

All this stuff is intuitive and logical, and my experience...Ed
 
Ed, great information. One question, with the cylinder mounted underneath wouldn't debris and such build up on the gland possibly causing the seals to wear out prematurely?
 
My cylinders ar outside the frame, so it is not an issue. A shield is easily built to take care of the problem, if they or it is/are under the dies...Ed
 
Thanks Ed,

Hope Washington has room for another maker out there. I hope to be in the NW part of the state by next year, this time.

I'd love to see that behemouth of a rolling mill you made in action.

Mark
 
Ed Schempp said:
My cylinders ar outside the frame, so it is not an issue. A shield is easily built to take care of the problem, if they or it is/are under the dies...Ed
Click to expand...
Oh, I see. I'm on the opposite end of the line from you. I've been building and repairing hydraulic/pnuematic cylinders for a little over ten years, but I have little experience in the field use of them. It's kind of funny but since I took up knife making I've learned more in past few months about the metal we use in our factory than I had in the 10 years. Now I'm learning more about the practical applications for our cylinders.
 
Hi Mark,
When you get out here Mark get in touch. I think Washington has something special happening. More flavor to the soup is always welcome...Take Care...Ed
 
Hey Ed,

I'll be out in the boonies of the NE part of the state. But I'm sure I'll have to come out of the woods ever so often. Cant wait to get back to the country. :)
 
Mark,

You will fit in with the NW knifemakers very well.

Wait until you see Ed's shop. The rolling mill is just one of many great tools Ed built. :eek:
 
Just watch out for Ray Rogers over where you're going or he'll soon have you out at night trying to seduce the bears, too! :D Thinking further on that, maybe Ray COULD use some company...... LOL
 
Thanks Ed..

question if you would..
why, if you know, is ele comparing to Gas HP not the same ?
I knew it was different but didn't think it was that far off.
thanks

and,, if we're talking governed gas or not?
 
Do you have drawings of your setup, Ed?

Thanks!
 
My dad told me "the figures don't lie, but liars figure". I don't know why these electric verse gas are inconsistant. Look at two stage compressors coupled to a five HP electric that puts out 20 SCFM @ 175. They are usually coupled with a 10 HP gas motor; maybe it is the start-up load handling difference. I'm just looking at the same compressor and the two different power applications. Maybe there is and engineer that can comment on this topic lurking.

I don't have plans currently available for my machines. Take a good look at Don Fogg's Press gallery; there are a lot of ways to skin a cat. I designed my press for my use and my corresponding equipment. Space, power requirements, other equipment all come to play in what your design should be.

I built my hydraulic power unit separate from the machines it powers. My two new 5 inch Prince (King Line) cylinder press cost about $700 to build. I got a lot more time and material and value in my dies...Ed
 
Ed Schempp said:
My dad told me "the figures don't lie, but liars figure". I don't know why these electric verse gas are inconsistant. Look at two stage compressors coupled to a five HP electric that puts out 20 SCFM @ 175. They are usually coupled with a 10 HP gas motor; maybe it is the start-up load handling difference. I'm just looking at the same compressor and the two different power applications. Maybe there is and engineer that can comment on this topic lurking.

I don't have plans currently available for my machines. Take a good look at Don Fogg's Press gallery; there are a lot of ways to skin a cat. I designed my press for my use and my corresponding equipment. Space, power requirements, other equipment all come to play in what your design should be.

I built my hydraulic power unit separate from the machines it powers. My two new 5 inch Prince (King Line) cylinder press cost about $700 to build. I got a lot more time and material and value in my dies...Ed
Click to expand...

thanks Ed thinking about "maybe it is the start-up load handling difference"
just if you didn't know or anyone else and I'm not getting mouthy here just info.
the compressor I have is a big old Kellogg vert. 2 stage
and it has a relief valve so you don't have a start up pressure problem
I almost find out the hard way about this,, the valve looks like a fitting that just connects
one of the air tubes to the tank.. it has a check valve in it operated by the
little air tube coming from the air/ele switch this valve unloads the air in the compressor
it's that spissss air sound you hear when the unit shuts down..
. just food for thought sorry it's OT

thanks aging I do want to find out why the difference though
I would think HP is HP do to it's basic beginnings. :confused:

a bunch of this post is helpful , and you have some very cool toys
to play with there :D
 
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