Thank you Kuraki!! This thread should be indexed.
I'll be starting from here when i'll be ready to set up my real deal press!!!
Hydraulic presses seem to be surrounded by legends, because fluid mechanics are not always intuitive.
For example, i'd be very curious to see a press failure...imho it won't be remotely as spectacular as many think
I'll be starting from here when i'll be ready to set up my real deal press!!!
Hydraulic presses seem to be surrounded by legends, because fluid mechanics are not always intuitive.
For example, i'd be very curious to see a press failure...imho it won't be remotely as spectacular as many think
I don't understand your point.
The pump is going to dictate max psi and max rate of flow based on cubic displacement per rev, and max rated RPM. My pump is rated for 3600 RPM and 3000 PSI. Additionally the relief valve on my valve spool can be adjusted to reduce the max pressure generated.
Tonnage is the product of cylinder area and system pressure.
Ram speed is the product of pump RPM and displacement divided by the volume of the cylinder.
Power requirements, outside efficiency drain, is calculated by the system pressure requirements and the rate that pressure is to be delivered.
This three legged stool can be varied to balance, or to increase one aspect of performance at the expense of another. Salem's point for example, assuming 2 pumps have max psi of 3000, a 1 cubic inch pump at 1750 rpm is the same GPM, will move a ram at the same speed, with the same HP requirements, as a .5 cubic inch pump at 3600 RPM.
This thread and others have frustrated me because the majority of the advice or comments have been about one or two legs in isolation of the third. It should be possible to simply calculate exactly what components are required to achieve a desired result, or conversely, to input available components variables and identify which other component would be needed to make up for the available one's shortcoming, outside the extreme example of a 20 hp motor on a pump rated for, say, 1000 PSI.
My original math was wrong, and I mistakenly bought a larger displacement pump than I intended, which doubled up into the result of a motor with insufficient power to generate even 500 PSI.
I have more than one option to resolve this, though a larger motor is likely the best, least expensive and highest performing option. I could get a pump with less displacement. I could get a larger cylinder, or a combination of the two. Either would increase the ability of this motor to develop greater tonnage at the expense of ram speed.
The recalculation I did above is telling me that simply getting a 5hp 3600 rpm motor will do what I originally wanted. A 5hp 1750 would do it at half the speed and have power on tap.
I'll double check those numbers again before I order, but it looks like a 5hp 3600rpm motor, and adjusting my relief valve down a bit since 3000 PSI requires slightly more than 5hp, will result in a press that moves 3.7 inches per second under no load and .7 inches per second under load, with a max tonnage output of 21 or 22 tons (guesstimating based on reducing relief valve set point).
I don't know what you mean about forging press PSI requirements being higher than most other hydraulic systems. 2500-3000 seems pretty standard in high flow unless you're talking about high pressure systems like enerpac which are low flow, or charge pumps and hydrostatic systems that are often lower pressure. It is something to watch for when shopping components for sure.