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DIY hydraulic presses, with electric pumps
Awl --
In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Iny links to DIY sites around? Thanks, -- Mr. PV'd Mae West (yer fav Congressman) to the Gangster (yer fav Lobbyist): Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just glad to see me?? |
DIY hydraulic presses, with electric pumps
"Proctologically Violated©®" wrote in message
... Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Iny links to DIY sites around? Oh, it just dawned on me: I in fact have an 80 ton bottle jack (manual), AND two hydraulic pumps/resevoirs from an old car lift. Is it straightforward to attach a hydraulic pump to a hand bottle jack? If so, what types of parts/valves/etc are req'd? DIY site? -- Mr. PV'd Mae West (yer fav Congressman) to the Gangster (yer fav Lobbyist): Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just glad to see me?? Thanks, -- Mr. PV'd Mae West (yer fav Congressman) to the Gangster (yer fav Lobbyist): Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just glad to see me?? |
DIY hydraulic presses, with electric pumps
On 2009-02-21, Jim Wilkins wrote:
On Feb 21, 11:58*am, "Proctologically Violated©®" wrote: Awl -- In particular, how does one size the motor/pump for a given tonnage? *Say, 10 tons. *Is tonnage the only issue? *See below. You can achieve almost any tonnage with any pump given a big enough slave cylinder and enough time. Work from the diameter of the slave cylinder and the required force to calculate how much hydraulic pressure is needed -- and then go from that to find out how fast a pump you need. I've got three ways to power the crimping heads by AMP for wire sizes from 1/0 through 4/0. 1) An EnerPac hand pump 2) A foot pump sold by Amp for the purpose. 3) An electrical pump (once) sold by AMP for the purpose. Of the three, the second one gives the best feel of what is happening. With nothing in the dies and the dies open, about two strokes is more than enough to close the dies and hit the pressure release (set to about 8500 PSI). The switchover from high volume to high pressure is close to instant. With a 4/0 terminal in the dies, and 4/0 wire in the terminal, I feel a little back pressure on the pedal as the terminal starts to deform, and up to nearly fully crimped. (This takes several strokes). Then the force required decreases noticeably as the high pressure slow pumping mode switches on, and the crimp is completed in this mode. The electrical pump doesn't even seem to change sound as it goes through these stages up to the 8500 PSI release point. The EnerPac hand pump takes more effort (of course it doesn't have as long a lever, and it doesn't have my weight behind it. The total stroke for this task is only about 1/2 to 3/4", so slow pumping is not a real problem. My log splitter uses a 5.5 HP gas engine to run an 11 CFM Barnes two- stage pump, driving a 3.5" cylinder at up to 2500 PSI. This works out to 12 tons. The parts all came from Northern Hydraulics long before I bought the thing. When the pump shifts to low range the piston speed is a little more than I'd want for a press unless it was doing a predictable production job. Otherwise log splitter hydraulic hardware seems reasonable. Anyone else try this? I've not tried it, since I have had the electrical AMP pump for a couple of decades before I finally got the crimp heads and dies to go with it. (One of those things in a government surplus auction which I had not even noticed until it was time to pack the stuff into the car. :-) The engine will drive the pump to 2500 PSI at about 3000 RPM, a sweet spot for low vibration. It stalls if I set it much lower so I don't know how well it would work if you direct-coupled the pump to a 1725 RPM motor. Not all low-cost hydraulic pumps have bearings suitable for a pulley's side load. Unless your hydraulic press is designed to accept the 8500 PSI range, I would suggest avoiding the crimper pumps (foot or electrical), as it could be easy to over-pressure it and break something. If you're interested in one of the foot pups at what I consider an excessive price, take a look at eBay auction #330055769330. They've got a $950.00 buy-it-now and have had it for a couple of months at least. I got mine during the lifetime of this "auction", from eBay, for a bit under $300.00, which I considered a reasonable price. The only other differences between them was that the one I got was yellow (as was the one I used back around 1964 or so), and this is blue, and the one i got had a link to where you could download the PDF for the manual, and this one they appear to have downloaded and printed the manual for you. :-) Here's a somewhat larger (3HP) electric pump to 10,000 PSI on eBay -- if you are interested in shoveling out some money. :-) # 140079292295 Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
DIY hydraulic presses, with electric pumps
"Proctologically Violated©®" wrote in message ... "Proctologically Violated©®" wrote in message ... Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Iny links to DIY sites around? Oh, it just dawned on me: I in fact have an 80 ton bottle jack (manual), AND two hydraulic pumps/resevoirs from an old car lift. Is it straightforward to attach a hydraulic pump to a hand bottle jack? If so, what types of parts/valves/etc are req'd? DIY site? -- Mr. PV'd At work we have a press that uses an air cylinder to pump a hand type pump. It might be easier to use an air cylinder to pump the bottle jack. Otherwise you have to try to find a way of getting the fluid in to the high pressure side of the bottle jack. I'm wondering if you could remove the bottle jacks pump piston, make a duplicate and drill a hole through it for hydraulic fluid, that might work. RogerN |
DIY hydraulic presses, with electric pumps
Proctologically Violated©® wrote:
Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Power = Force x Velocity (there may be a constant involved if you use imperial units). I figure that using a 7.5 hp motor and a 10 ton load, you get about 2 inches per second at 100% efficiency. But I doubt you'll get more than half that in reality. And you probably don't need maximum force and maximum velocity at the same time. So you can get better performance using a two-stage pump which can supply a high flow rate at a low pressure or a low flow rate at a high pressure and switch automatically between the two. It's worth noting that an electrically powered press is a lot more dangerous than a hand powered press. If you're using a hand powered press and you get your hand trapped in it, you stop pumping because it hurts. A motor won't do that. Best wishes, Chris |
DIY hydraulic presses, with electric pumps
"Proctologically Violated©®" wrote in message ... "Jim Wilkins" wrote in message ... On Feb 21, 11:58 am, "Proctologically Violated©®" wrote: Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My log splitter uses a 5.5 HP gas engine to run an 11 CFM Barnes two- stage pump, driving a 3.5" cylinder at up to 2500 PSI. This works out to 12 tons. The parts all came from Northern Hydraulics long before I bought the thing. When the pump shifts to low range the piston speed is a little more than I'd want for a press unless it was doing a predictable production job. Otherwise log splitter hydraulic hardware seems reasonable. Anyone else try this? The engine will drive the pump to 2500 PSI at about 3000 RPM, a sweet spot for low vibration. It stalls if I set it much lower so I don't know how well it would work if you direct-coupled the pump to a 1725 RPM motor. Not all low-cost hydraulic pumps have bearings suitable for a pulley's side load. ====================================== I may have stumbled on an even easier solution: http://www.mytoolstore.com/astro/asthyd01.html shows a 12 ton air-operated bottle jack. I would assume the travel is orders of magnitude faster than manually pumping the jack. $150 gets a 20 ton. All's I gotta do is build something of a frame for it, and it should be good. At $76 for the whole unit, I don't think I could get a lovejoy coupling for a hydraulic motor/pump. You could get a press from harbor freight for about $120.00 and put the jack on it you pointed out. http://www.harborfreight.com/cpi/cta...temnumber=1667 Or you could get a bigger press for the 20 ton jack from them also at $239.00. http://www.harborfreight.com/cpi/cta...emnumber=32879 Richard W. |
DIY hydraulic presses, with electric pumps
On Sun, 22 Feb 2009 22:53:57 +0000, Christopher Tidy
wrote: Proctologically Violated©® wrote: Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Power = Force x Velocity (there may be a constant involved if you use imperial units). I figure that using a 7.5 hp motor and a 10 ton load, you get about 2 inches per second at 100% efficiency. But I doubt you'll get more than half that in reality. And you probably don't need maximum force and maximum velocity at the same time. So you can get better performance using a two-stage pump which can supply a high flow rate at a low pressure or a low flow rate at a high pressure and switch automatically between the two. It's worth noting that an electrically powered press is a lot more dangerous than a hand powered press. If you're using a hand powered press and you get your hand trapped in it, you stop pumping because it hurts. A motor won't do that. Best wishes, Chris Use air over oil, and a small pump to move to the top of the part. I just completed a 700 ton and a 200 ton ,closed loop, air over oil . Used a plc and hmi for programming both ramp and target pressure. Dave B |
DIY hydraulic presses, with electric pumps
On Feb 22, 6:05*pm, Dave B wrote:
Use air over oil, and a small pump to move to the top of the part. That can be dangerous: compressed air stores significant energy, it can shatter an item in the press and send pieces flying. With oil only, an item in the press shatters and the oil pressure immediately drops, before projectiles form... My preference is for a two-stage pump, either hand or power, so the piston moves to take up slack at the fast speed, then falls back to the slow speed when the pressure rises. |
DIY hydraulic presses, with electric pumps
On Mon, 23 Feb 2009 11:49:43 -0800 (PST), whit3rd
wrote: On Feb 22, 6:05*pm, Dave B wrote: Use air over oil, and a small pump to move to the top of the part. That can be dangerous: compressed air stores significant energy, it can shatter an item in the press and send pieces flying. With oil only, an item in the press shatters and the oil pressure immediately drops, before projectiles form... My preference is for a two-stage pump, either hand or power, so the piston moves to take up slack at the fast speed, then falls back to the slow speed when the pressure rises. It is not if you use a correct intensifier. http://www.airhydraulics.com/Hydraul...aulicPress.htm It's done everyday. |
DIY hydraulic presses, with electric pumps
On Mon, 23 Feb 2009 11:49:43 -0800 (PST), whit3rd
wrote: On Feb 22, 6:05*pm, Dave B wrote: Use air over oil, and a small pump to move to the top of the part. That can be dangerous: compressed air stores significant energy, it can shatter an item in the press and send pieces flying. With oil only, an item in the press shatters and the oil pressure immediately drops, before projectiles form... My preference is for a two-stage pump, either hand or power, so the piston moves to take up slack at the fast speed, then falls back to the slow speed when the pressure rises. Here are some of the presses I have done (last year) Air over oil,air intensifier and closed loop servo valve http://s32.photobucket.com/albums/d1...nt=200ton3.jpg http://s32.photobucket.com/albums/d1...nt=200ton2.jpg http://s32.photobucket.com/albums/d1...ress_Retro.jpg Dave B |
DIY hydraulic presses, with electric pumps
"Dave B" wrote in message ... On Mon, 23 Feb 2009 11:49:43 -0800 (PST), whit3rd wrote: On Feb 22, 6:05 pm, Dave B wrote: Use air over oil, and a small pump to move to the top of the part. That can be dangerous: compressed air stores significant energy, it can shatter an item in the press and send pieces flying. With oil only, an item in the press shatters and the oil pressure immediately drops, before projectiles form... My preference is for a two-stage pump, either hand or power, so the piston moves to take up slack at the fast speed, then falls back to the slow speed when the pressure rises. Here are some of the presses I have done (last year) Air over oil,air intensifier and closed loop servo valve http://s32.photobucket.com/albums/d1...nt=200ton3.jpg http://s32.photobucket.com/albums/d1...nt=200ton2.jpg http://s32.photobucket.com/albums/d1...ress_Retro.jpg Dave B Very nice. But that makes a two or three stage pump look very simple. |
DIY hydraulic presses, with electric pumps
On Mon, 23 Feb 2009 22:04:22 -0600, "Elliot G"
wrote: "Dave B" wrote in message .. . On Mon, 23 Feb 2009 11:49:43 -0800 (PST), whit3rd wrote: On Feb 22, 6:05 pm, Dave B wrote: Use air over oil, and a small pump to move to the top of the part. That can be dangerous: compressed air stores significant energy, it can shatter an item in the press and send pieces flying. With oil only, an item in the press shatters and the oil pressure immediately drops, before projectiles form... My preference is for a two-stage pump, either hand or power, so the piston moves to take up slack at the fast speed, then falls back to the slow speed when the pressure rises. Here are some of the presses I have done (last year) Air over oil,air intensifier and closed loop servo valve http://s32.photobucket.com/albums/d1...nt=200ton3.jpg http://s32.photobucket.com/albums/d1...nt=200ton2.jpg http://s32.photobucket.com/albums/d1...ress_Retro.jpg Dave B Very nice. But that makes a two or three stage pump look very simple. Wasn't meant to be simple. I just stated for the op to use air over oil............very simple Dave B |
DIY hydraulic presses, with electric pumps
On Saturday, February 21, 2009 at 10:58:33 AM UTC-6, Proctologically Violated©® wrote:
Awl -- In particular, how does one size the motor/pump for a given tonnage? Say, 10 tons. Is tonnage the only issue? See below. My buddy needs one made, is getting a price, but it seems like the price keeps climbing, and they are claiming he needs 7.5 hp for 10 tons. We had a Daco 55 ton press, and I'd swear that press had only mebbe a 1-2 hp motor. BUT, it operated very slowly. I would imagine for a *faster* stroke at a given tonnage, hp increases, as the hydraulic "mechanical advantage" is probably decreasing with increased speed, so a bigger motor is req'd. How to calc?? Iny links to DIY sites around? Thanks, -- Mr. PV'd Mae West (yer fav Congressman) to the Gangster (yer fav Lobbyist): Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just glad to see me?? http://www.surpluscenter.com/Tech-He...sp-HP-GPM-RPM/ http://www.surpluscenter.com/Tech-He...eed-Torque-HP/ |
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