All of the things that Billy said with the following exceptions:
-Minimum 6" dia cylinder (the larger the diameter the lower pressure required on the hydraulic lines)
-Build in an adjustable "by-pass" valve, that is pressure adjustable...meaning that you can adjust the valve to by-pass when a specific line pressure is reached.
- For a hydraulic forging press, build the thing 2X more beefed up than you think it needs to be....and then build it some more!
When I built my last press, I used a 12" "I" beam with 1/2" flanges and a 5/8" thick web....and I still had to add 3/8" gusset plates between the flanges to keep it from flexing during use. (Mine is a "C" frame design....I just like them better, and they have a small footprint than an "H" frame press)
One thing that scares the daylights out of me is when I go into someone's shop and they are running a small diameter cylinder on a press (5" or less), and are running line pressures 3,000psi +! If one of those lines gets even a pin hole in it at that pressure....it will cut you in half like a laser! (Most hydraulic lines are only rated for UP TO 3,000psi, unless you get hoses special made, and those are out of this world expensive.)
Have a look at Don Fogg's page and don't miss the 5 or 6 other pages with links at the bottom of the page.
http://www.dfoggknives.com/hydralic.htm
There is a booklet he sells there too which runs through specs and designs by an actual engineer.
-the Baston book
A pre made shop press is usually unsuitable because it achieves its high power with a large cylinder at a very slow stroke speed
A forging press is usually recommended to have at least 1 or 2 inches per second stroke speed so you can move metal while it is still hot.
If you start doing calculations you will see that it is easy to get a high tonnage, but at a slow stroke speed because of the volume of fluid required.
This takes a large pump and motor.
You may have to reach some sort of comprise on a slightly smaller 5" cylinder instead of 6".
It starts costing real $ to up your pump volume, motor HP and wiring size above 5 hp
Is 50 tons twice as good as 25 ? probably not as good as a fast 25
The larger size will allow you to run larger dies and keep the same PSI at the die level...but there must be a practical limit..
in the numbers Billy gave he is running psi is 21.5 tons
Buy the book , look at what others have done and do the calculations with what you can buy locally.
I would tend to stay with 5 or 6 inch cylinder, go larger on the pump volume and keep the pressure down to keep the stroke speed up so you can get more squeezes per heat in.
When the steel is hot, you wont' need huge pressures to move the steel and are better served by gradual reductions to preserve your patterns.
the difference between the pump volume at 5" and at 6" is significant.
Don Fogg's specs
10 hp dual pump hydraulic station pushing
16 gallons a minute at psi.
5" double acting hydraulic cylinder with an 8" throw.
Works out to 14.7 Tons
Indian George
SUPPLIER PART# DESCRIPTION COMMENTS
NORTHERN -C161 BARNES 2 STAGE PUMP -11GPM
-C161 PRINCE STANDARD 4-WAY CONTROL VALVE
-C161 7 GALLONS HYDRAULIC OIL TANK MUST CLEAN THE INSIDE WELL
-C161 RETURN LINE FILTER
-C161 SUCTION STRAINER THIS GOES INTO THE TANK
FITTINGS AND HOSES YOU WILL NEED 3 HI- PRESSURE HOSES AND LOW PRESSURE HOSE FOR THE RETURN.
-C161 GLYCERIN FILLED GAUGE 0-PSI
SURPLUS CENTER 10- ELECTRIC MOTOR I USE A 3 HP AT RPMS
09 HYDRAULIC CYLINDER I USE A 4 1/2" BORE X 8" STROKE WITH THE PUMP AND MOTOR SHOULD GENERATE 24 TONS
"If I ever build another one it would be a H press with a minimum 5" cylinder."
__________________
Eric Fleming
WIP with automated stroke timing
http://www.bladeforums.com/forums/showthread.php?t=&highlight=press
Material list
http://www.bladeforums.com/forums/attachment.php?attachmentid=&d=
Motor – 7.5 HP
Pump – Single stage 5.2 GPM (Single stage is necessary to get repeatable timing for an automated stroke)
Cylinder – 5” X 8” Stroke
calculations.
http://www.bladeforums.com/forums/attachment.php?attachmentid=&d=
**************
220V motors are practical in these sizes
Thanks for all the input from everyone. I notice most of you are using large horsepower motors. Is there a reason to use a large motor or would a 110v motor putting out pressure be enough? Maybe if we get enough information and pictures we can make this a show us your presses thread.
I would say that a 5hp motor is about minimum required. I started out with a 5hp rpm and then switched to a 5hp rpm. The quality of the motor also makes a huge difference. An elcheapo air compressor will over heat from the constant cycling. Spend the extra $ and get a good TEFC Leeson or Baldor motor.
I am running a 5" cylinder on my press. But would prefer to have a 6".
Also, as Ed said, A bypass or pressure relief valve is a must for safety reasons. A pin hole leak in a hose at psi will drill a hole through you...
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steve kelly 043-1.jpg
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Thanks for all the input from everyone. I notice most of you are using large horsepower motors. Is there a reason to use a large motor or would a 110v motor putting out pressure be enough? Maybe if we get enough information and pictures we can make this a show us your presses thread.
"would a 110v motor putting out pressure be enough?"
Are you looking at premade hydraulic power pack units?
They are no good for forging, as I mentioined earlier, pre-made shop presses may generate enough force, but the ram speeds are too slow.
If they would work well, then everyone would use one and no one would be building presses.
Some people rebuild log splitters, but if you don't already have one to start with, skip that it's cheaper to start with parts.
Horsepower required is part of the calculations on Eric Flemings Excel Spreadsheet
http://www.bladeforums.com/forums/attachment.php?attachmentid=&d=
and I suspect that they are based on the specs in Bastons book
Horsepower =PSI X GPM X Efficiency Rate(100% used) /
Sure you could use less, but then you would have to get your RPM and GPM specs down and then you may not be happy with it.
On Baldor's website for example a 5 hp motor is not available in 110v, it's not practical.
(you may have a 110V air compressor that is listed as 5 or 7 hp or something crazy like that
but those are total BS numbers that they should have stopped using after the lawsuits.)
http://www.wisedan.com/aircomp.html
220v vs 110v
If you go down to a 3 HP motor, you can get a dual voltage motor that could be wired 110 or 220,
but at 110 it would draw 30 amps and need 35 amp breaker and wiring,
it is actually cheaper to go 220v
rpm motor will give you the most pumping volume as pumps are listed as displacement per revolution.
Why are you thinking 110 over 220?
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Though they generally last for years, even with inspections, there are many hydraulic cylinder problems that can cause failure. Below are the 9 most common hydraulic cylinder failure causes that must be addressed in order to maintain effective hydraulic systems.
Reasons Behind Various Hydraulic Cylinder Failures
Along with the above reasons, according to statistical research published by MDPI in , the most common causes of hydraulic cylinder failure are as follows: Fluid contamination and oil pollution contribute to about 41.1% of cylinder failures. Improper maintenance is the cause of approximately 12.6% of failures, while outsourced parts and physical damage to the cylinder cover 10% and 6.5% of failures, respectively. Intense oil viscosity and the wrong choice of filter are at fault for 5.2% and 1.7% of failures, respectively, while about 1.7% of failures are caused by excessive vibrations. 9% of the causes of hydraulic cylinder failure are uncertain.
Seal Failure
Seals are the most easily damaged component of a cylinder. Cylinder seals are the weakest part of the cylinder and can fail for many reasons including scratched piston rods, breaking down from the heat, contaminated fluid, or pressure spikes.
Abrasives, incorrect fitting, and chemical erosion can also cause hydraulic cylinder piston seal failure and seal leakage. A hydraulic seal that has been damaged by any of these occurrences and experienced leakage can ruin the cylinder's ability to maintain a certain pressure.
Fluid Contamination
One of the most common reasons for hydraulic cylinder failure is contaminated fluid. When foreign, abrasive particles become trapped in the fluid, they scratch the inside of the cylinder, ruin the finish of cylinder rods, block ports, and damage seals and fittings. Though hydraulic fluid does degrade with time, faulty wiper seals are generally the cause of accelerated fluid contamination.
Extreme Temperatures
Extreme temperatures affect the function of hydraulic cylinders:
- In extreme heat, polyurethane seals will lose their effectiveness and their shape. In the cold, the seals will become brittle, losing their elasticity.
- Either extreme temperature will damage the fluid in the hydraulic cylinders. The harsh conditions will affect the viscosity of the hydraulic fluid and lead to leakage and system failure.
Hydraulic Cylinder Side Loads
A hydraulic cylinder is designed to apply linear force along an axis that is aligned with the cylinder. When hydraulic cylinders are installed improperly, the force is applied perpendicular to the intended direction and side loading occurs. Sideloading causes uneven wearing because the cylinder rod pushes and the piston drags with more force on one side than the other.
Moderate sideloading will accelerate the degradation of the hydraulic cylinder and the cylinder will need to be repaired sooner. However, excessive side loading and uneven wear to various components can have more catastrophic results, as it leads to the failure of the system and a potentially dangerous situation. In summation, with uneven loads, hydraulic cylinders fail.
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Piston Damage
There are a few causes for piston damage; it is possible the nut or piston retaining device will become looser over time and pistons will often wear out with time like any mechanical equipment. Also, side loading or contaminated fluid could cause damage to the pistons and piston rod. Ultimately, the piston damage will cause complete hydraulic cylinder failure and the device will lose power.
Incorrect Pressure
In order to perform effectively, it is essential to monitor and maintain precise and controlled internal hydraulic pressure. When there are pressure variations within the system that are not according to the manufacturer's specifications it could lead to potentially dangerous conditions. Regular checks and adjustments should be made to comply with the system's specifications.
Corrosion
Another common problem with hydraulic cylinders is corrosion; corrosion appears as rust and pitting on the piston rods and stages of the cylinder. Equipment is sometimes stored outdoors, with the cylinders extended, exposing the rods to the elements.
Over time, specks of rust will form and then develop into pits and as soon as the cylinder is retracted, the rod will destroy the seal of the cylinder. This problem can be eliminated by regularly using the cylinder so a micro oil film can form on the cylinder rod. Otherwise, hydraulic cylinder failure is inevitable.
Cylinder Bore Scoring
Cylinder bore scoring presents as deep gouges or harsh scuffs to the interior of the bore walls. This will be most noticeable where the piston is in its fully extended position at the mouth of the barrel. In the fully extended position, there is less support which results in increased friction and forces. Cylinder bore scoring might occur if cylinders are not mounted properly or cannot accommodate alignment changes. Increased side-load forces, which lead to a crooked cylinder rod, can also cause cylinder bore scoring. Scoring is most often found in long-stroke cylinders.
Split Welds
Split welds are catastrophic failure signaled by separation or cracks in welded surfaces, like mounting points. They are generally believed to be a sign that atypical or excessive force has been applied to the cylinder.
There are many situations where this kind of damage might have occurred, from improper operation to external impact to the poor condition of the hydraulic system. A split weld should not be ignored, if untreated it could have unfortunate consequences, from damage to the equipment to potential injuries to personnel.
Conclusion
Hydraulic cylinders can fail for a number of reasons, from seal failure to pressure and temperature issues, and understanding why the cylinders can fail will reduce the chances it occurs. Regular checks are an essential part of ensuring the overall system is working safely and effectively.
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