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Benders and Bending Which bender is best? How do you use a bender? How do you calculate bends? Everything Bender related...


Benders and Bending Which bender is best? How do you use a bender? How do you calculate bends? Everything Bender related...

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  #21  
Old 01-05-2013, 12:44 PM
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Originally Posted by bullnerd View Post
Very good.

Do either of you think that you "overbuilt" your machines at all? Like ,could you have gotten away with thinner/lighter materials anywhere?
main frame plates could have been thinner but didnt have any thinner plate at the time.
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  #22  
Old 01-05-2013, 01:04 PM
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Originally Posted by bullnerd View Post
Very good.

Do either of you think that you "overbuilt" your machines at all? Like ,could you have gotten away with thinner/lighter materials anywhere?
The critical stress areas on my machine are the main die shaft and the main die drive pin. The smaller drive pin is the most heavily stressed. If I had it to do over, I would use a drive platten that the die would bolt down to. The arms themselves use much thicker material than needed.
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  #23  
Old 06-10-2016, 05:24 PM
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Anyone have any specs for a motor pump and ram that I can hunt down and buy to convert my bender to electric I will only be bending 1 1/2" x .120 (38x3mm) an electric conversion kit for a jd2 here in Australia is over $3000 but I can get motor pump and ram off eBay for around $1000 just wanna make sure I'm aiming for the right specs when I start looking.
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  #24  
Old 06-15-2016, 04:23 PM
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I built a got trikes bender and put a "lift kit" on it with a 24" stroke cylinder and run it with my hydraulic power pack. With this set up I can bend 100 degrees in one stroke in about 6 seconds. I bend square handles for ice pumps for a local business. Each handle has 4 bends for the main hoop and two for each of the attachment tubes. These are all out of .75" square tube. 8 bends per handle. Once I have them all marked out, I can do 100 handles in a 10 hour span. That's 800 bends. The part that really helps speed it up is I installed a dump valve in the hydraulics that I have set to dump the pressure once the bender arm hits the desired angle. Here's some pictures. I will try to get a video for you.

Set up with the dump valve

Dump valve

Adjustable dump
This is what triggers the dump valve. It's somewhat adjustable you fine tune to accommodate spring back

And here's what I can do in 10 hours

And here's what I can do in 10 hours
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  #25  
Old 06-15-2016, 04:35 PM
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That's pretty awesome do you know the specs for motor valve and ram I'm trying to hunt stuff down here in Australia to convert mine but so difficult not many company's will give you the time of day if your trying to build something at home and every thing is running into thousands of dollars yet u can find everything in eBay cheap as chips I just dunno what specs to look for.
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  #26  
Old 06-15-2016, 05:06 PM
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I'll see what I can dig up. I actually got this valve from a member on another site. I believe he was from the UK. I think he is even on here. If I can remember correctly Baloo was his user name I believe. I couldn't find one here in Canada and he was generous enough to send me one of his spares. No one here had a clue what I was talking about. I hear you on the no one wants to help thing. That's why I like places like this where people are always willing to help.

Last edited by Bstomper; 06-15-2016 at 05:08 PM.
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  #27  
Old 06-15-2016, 05:12 PM
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If I could figure out how to search my old posts I could find out more info quicker
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  #28  
Old 06-15-2016, 05:35 PM
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Thanks heaps so far this is what Iv been looking for here in Australia and the AUS$ price I still have to add tax onto these prices which is another 10% I got the specs for these parts off the home brew bender page which was the only place I could find a complete list of parts with specs

1/ - Power unit
1.5 KW single phase , 5.5 ltr/min , relief set to 2000 psi , 5.0 ltr tank
Price - $1077.00 + tax

2/ - 3.0" x 24" stroke cylinder - female clevices with 1" pins
Price - $350.00 + tax

3/ - 3 position manual directional control valve
Price - $206.00 + tax

This comes to about $1800 including tax this dosnt even include hoses and fittings which will cost another few hundred $$
To put into perspective the jd2 electric conversion here in Australia will cost me over $3000
Hate how everything so expensive here
( my weekly wage is $1200 I have about $300 per week to spend on toys/tools etc so going to take a while to save so wanna make sure the system works )
Cheaper choice I found is a 12v tipper trailer system this would be about half the price has anyone tried this??
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  #29  
Old 06-15-2016, 10:01 PM
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I just downloaded a pretty cool phone app for hydraulics you enter in the ram specs
Ie
Piston diameter - 3"
Rod - 1.75 ( 1 3/4")
Stroke - 24"
Pressure - 3000psi
Time can ether enter stroke in or out I put 10 secs out
And it spits out
Oil flow rate = 4.41 gpm
Force 21200 lbs
And heap of other info so hope I can now find some parts that will match and go at the speed I want just have to search for a pump with working flow rate of around 4.5gpm
10 secs is pretty quick tho and I won't be bending that big a pipe (1.5" x .120) so could maybe go a smaller bore size. Still have to do more research tho.
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  #30  
Old 06-16-2016, 02:35 AM
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This is the animal that you are looking for. It's proper name is end stroke valve. It just gets "T'ed" into the pressure line and the return line of your bender hoses. It is a normally closed valve and when it is activated by the moving bender arm it opens and dumps the pressure in the pressure hose and diverts it to the return line stopping the bend cycle.
http://www.flowfitonline.com/hydraul...ally-closed-12
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  #31  
Old 06-16-2016, 02:50 AM
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That's pretty cool will look into it once I'm bending
First I have to get a hydraulic set up
Do you have a link or any info on the hydraulic power pack your using
Would be greatly apretiated probably wouldn't need anything as fast as what you say yours runs at but need to start looking somewhere
Cheers 👍
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  #32  
Old 06-16-2016, 09:10 AM
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Heres another stroke limiter. They are used a ton on farm implements as a depth control.
http://www.ebay.com/itm/PARKER-PRINC...EAAOxy8HlSc~xA
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  #33  
Old 06-16-2016, 12:25 PM
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Quote:
Originally Posted by ducas99 View Post
I just downloaded a pretty cool phone app for hydraulics you enter in the ram specs
Ie
Piston diameter - 3"
Rod - 1.75 ( 1 3/4")
Stroke - 24"
Pressure - 3000psi
Time can ether enter stroke in or out I put 10 secs out
And it spits out
Oil flow rate = 4.41 gpm
Force 21200 lbs
And heap of other info so hope I can now find some parts that will match and go at the speed I want just have to search for a pump with working flow rate of around 4.5gpm
10 secs is pretty quick tho and I won't be bending that big a pipe (1.5" x .120) so could maybe go a smaller bore size. Still have to do more research tho.
4.5gpm at 3,000psi is going to take about 7.9hp (5.9kw). I'm guessing you will not have that big of a motor available (unless you plan to run it off petrol).

If you are designing for a 1hp (0.75kw) motor, you can do 3,000psi max at 0.57gpm, so a more typical pump selection would be 0.5gpm for a 1hp motor. Remember your max bending speed, when optimizing all the geometry and hydraulic selection, is purely a function of the max tube capacity bending torque and the power of your motor.

One of these days I need to find a few hours to write up a primer on bender hydraulics with some of the math and geometry to help folks out with ram, pump, motor/drive, and valve selection.

Quote:
Originally Posted by CarterKraft View Post
Heres another stroke limiter. They are used a ton on farm implements as a depth control.
http://www.ebay.com/itm/PARKER-PRINC...EAAOxy8HlSc~xA
Are you guys thinking of using that type of end of stroke valve as an auto stop? I don't think you'll get a very repeatable stop location with something like that because the transition to open is not abrupt. Better to have an electric switch (or better yet, encoder-based control) and solenoid valve to stop the cycle.
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  #34  
Old 06-16-2016, 01:31 PM
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Quote:
Originally Posted by TheBandit View Post
Are you guys thinking of using that type of end of stroke valve as an auto stop? I don't think you'll get a very repeatable stop location with something like that because the transition to open is not abrupt. Better to have an electric switch (or better yet, encoder-based control) and solenoid valve to stop the cycle.

Wasn't really my idea, Bstomper is using a similar valve on his bender above to automate(ish) the bending. While I agree in theory there might be better ways to control the bending precisely hydraulics are old as dirt and the facts are the facts. I bet he gets very repeatable bends on his machine using the old school dump off valve.

If you think about the mechanics of the valve (spool) it is likely the exact level of oil flow precision as the solenoid/encoder/transducer setup you posed just cutting out the electro part of the equation.

Where this goes out the window is for different angles and springback for each bend. It would have to be dialed in at each bend angle and spring back calculated (a total waste). But if you are doing 1000 90* bends per day in the same material it sounds perfect to me.
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  #35  
Old 06-16-2016, 01:32 PM
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I agree. The reason i believe I can get very accurate repeatable bends is because my bender arm moves fast. 90* in 5-6 seconds. I just pull the lever wide open and let it stop when it does. If the arm wasn't so fast I don't think it would be as accurate.
As far as my hydraulic power pack goes, it is a complete unit that runs on a 240v electric motor. I know very little about hydraulics. The guy I bend handles for designed it for me so that I could use it to run my bender, a press and a log splitter. I cost me about $1700 to build.
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  #36  
Old 06-16-2016, 01:34 PM
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I apologize. It is speculation on my part since I only have experience using solenoid valves for that kind of function. I have used limit valves on pneumatic systems and I know those are not very repeatable for positioning, but hydraulics are another animal.
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Last edited by TheBandit; 06-16-2016 at 06:34 PM.
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  #37  
Old 06-16-2016, 05:28 PM
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The home brew bender I got the specs from runs a 1.25gpm pump with a motor that runs at 3450 rpm with a 3x24" ram
I can find a pump and ram but the fastest single phase motor I can find is only about 1800rpm so don't know what to do
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  #38  
Old 06-16-2016, 05:37 PM
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. silly idea, please ignore this post .
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  #39  
Old 06-17-2016, 12:32 AM
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Quote:
Originally Posted by CarterKraft View Post
Wasn't really my idea, Bstomper is using a similar valve on his bender above to automate(ish) the bending. While I agree in theory there might be better ways to control the bending precisely hydraulics are old as dirt and the facts are the facts. I bet he gets very repeatable bends on his machine using the old school dump off valve.

If you think about the mechanics of the valve (spool) it is likely the exact level of oil flow precision as the solenoid/encoder/transducer setup you posed just cutting out the electro part of the equation.

Where this goes out the window is for different angles and springback for each bend. It would have to be dialed in at each bend angle and spring back calculated (a total waste). But if you are doing 1000 90* bends per day in the same material it sounds perfect to me.
You are correct. I would never use this system to just do a few bends. I have it set up for just this specific task of bending these handles at 90* and I have it set for spring back on this particular tube for a 90* bend. If I wanted to do repeated bends of a different angle I would have to make a different mount plate. I would never use this for only a few bends. I take it completely off.
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