hydraulic power question

[forgemaster]

With a regen circuit, once the ram contacts the job and actually starts pushing, it reverts to a normal situation, ie all the oil from the front of the piston goes back to the tank, and all the oil from the pump goes to the back of the ram to push, on the return stroke the ram reverses at its normal speed which is going to be quicker that the normal forward stroke as the rod takes up some of the cylinder space, hence you need less oil to acutate the movement (in reverse). Regen is only of use when you want a fast approach with no load, you are taking the oil that is being displaced from in front of the piston and routeing it to the back of the cylinder where it is admitted with the oil coming from the pump, once the system starts to load up the valving switches the hyd circuit back to a normal standard configuration. The reason the ram wil still move forward (in regen) is the differential in surface area of the piston from front to back caused by the piston rod taking up some of the room on the piston front. If you tried it on a piston without a rod the piston would not move as there would be no difference in the 2 surface areas front and back of the piston, it would be in a state of equilibruim, equal pressures (surface areas) on both sides = no movement.

Phil

[bkforge]

Since you got the hydraulic power pack and cylinder (which is alone worth the $250) build up a system and try it out. If it is not "fast enough" get a two stage pump and a fast motor. Just design the press frame heavy enough to withstand where you want to end up. I've been using a 25 ton/two stage(16 gpm/4gpm)/3600 rpm/5 hp electric motor for 15+years and it is great. But it's not hammer. But it does a lot you can't do w/ a 50 lb little giant. For making flat dies, you just need to decrease the contact area, ie. tilt the workpiece to contact the corners only or use a smaller surface area like a fuller first, then the flat dies to "flatten", kinda like a hand hammer on large stock. The press is great down to 1/4" thickness then the hammer/powerhammer/treadle hammer takes over, especially for drawing out. It can be done with press but you need some large diameter drawing dies for best results. If the dies are too small it takes aggressive bites and makes cleanup difficult--this is where slow speed is good.....try the pump you have and learn

Bill

[Weld Inc]

I am looking into going with an accumulator. With my five gpm pump and five inch bore cylinder what size accumulator is sufficient to make it worth the extra cost of accumulator and valving? Is a piston or bladder type better? What type of accumulator circuit is recommended? Thanks for all the help everybody!