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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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  #41  
Old 02-24-2006, 05:58 PM
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Looking good as always. Must feel good to start seeing the light near the end.

Jay
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  #42  
Old 02-24-2006, 06:17 PM
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Quote:
Originally Posted by JWBURES
The Bandit, I have been following this thread from the start. Super nice job, but I have come to the conclusion, I don't like you all that much. Envy gets the better of me.
LOL. I'm not sure exactly how to take that, but thanks for the complements.

Quote:
Originally Posted by smashmetal
Nice work! I've been following the thread since the get go, looks like you'll have no problem bending a single thing. I have noticed one thing though, the way you have your dies set up, It seams like you'll be a little limited in rotating the tubing during multiple bends?
Thanks smash! Yes, there is a lot of blockage near the clamp on the main die for multiple bends. I did my best to make room, but I will still have to carefully plan multiple bends before executing them. In addition to considering the bend order and direction, I will have to keep in mind that both ends of the tubing will be swinging around the shop.

I think the Bend Tech Pro software with the bend simulator will really help me to see if I am going to have issues with interference.

One contrasting element between my bender and the ones currently being sold (ie RMD 150) is that those benders use a spindle to drive the forming die, while I am using a single cantelevered drive pin. I did this so I could use much less expensive dies (Pro Tools are around $150-200 versus $400-500+ for RMD). In order to use a drive pin like this, the structure it mounts to must be very rigid and the hole it fits in must be a tight fit. This prevents bending loads, placing the pin under dominantly shear loading. That is why the main die arm is sized the way it is, unfortunately blocking the area under and away from the U-strap.

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Originally Posted by sapper
Looking good as always. Must feel good to start seeing the light near the end.
Thanks Jay! You have no idea.
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  #43  
Old 02-27-2006, 11:30 PM
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UPDATE

Some time back, Cris (aka "fabcam"), the maker of Bend-Tech, generously donated a copy of Bend Tech for my use. Through our relationship, I was able to get on board as a beta tester for his latest Pro product and I am finally getting to use the software to bend real tubing!

I don't think this is what Cris originally had in mind for the software, but I am going to be using it to design the hardlines for the hydraulics. To get a feel for the software and working with my new hand tubing bender, I started work on a cord wrap to hold the bender's power cord. This is the first tubing I have bent for myself, but just imagine this was a bumper, rollcage, or a set of rock sliders.

I laid out my part using Bend-Tech Pro. It took all of about five minutes to calibrate the software and another five to design my part. The software is incredibly easy to use. After plugging in my desired dimensions, Bend-Tech generated an easy-to-follow instruction sheet and gave me a step-by-step pictorial of how to make my bends. Here is a screenshot.



The software told me the correct length to cut the tubing and where to mark for the beginning of each bend. After marking the tube, it was a snap to make the bends. I didn't have to trim the ends or anything: the length was perfect on the first try!



I welded the tubing some small pieces of plate, drilled them to accept fasteners, and attached them to the frame using some metal screws.



Here it is with the power cord wrapped up!



I originally wasn't planning to make this part, but after searching around I couldn't find a dang thing off the shelf. This was the perfect mini-project to get familiar with the tubing and the Bend Tech software. I am very happy with the results! :)
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  #44  
Old 03-02-2006, 03:06 AM
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UPDATE

Next week I will demonstrating the tube bender to my mechtronics class to show the autostop controller do its thing. I don't plan to have the bender completed (still a ways off from that), but I do need all the hydraulics working and enough of the machine together for people to understand what it does. Feeling ambitious, I though it would be good to have the main forming die mounted, which requires some modifications.

Below: First I fixtured the die and used a coax to center on the pressed/welded sleeve.



Below: I ran a rectangular pass using a large end mill, working my way down about 0.100 per pass. This gave me a nice cross section of the fit between the tube sleeve weld and the die. I tried getting a picture, but it was just impossible to see. The weld used to hold the sleeve to the die had no penetration near the root. This is probably not too important since the weld doesn't support any significant loading, but it may be something for Pro Tools to address.



Below: After I got through with the mill, what was left of the center sleeve just fell out.




When I was done milling out the sleeve, I went back with the coax to see how close to center I was on the hole the sleeve fit into. It turns out that the center had shifted quite a bit. So I checked the locations of the pin holes in the die and found they were not centered about my originally measured point either. I have decided I need to refixture the die and indicate off the tube interface surface (the outside diameter of the die), find a center, and then procede to machine out the center of the die.

Eventually I will have a larger hole in the center of the die where I can fit a larger sleeve for fitting over the bender's shaft.

Since I didn't have the tools for properly centering on the die, I decided to abandon that step and not have the die ready for the demonstration.

Below: The next project was mounting the shaft encoder. This device is what measures the bend angle. I designed this aluminum weldment to cantilever the encoder from the follower die arm to under the main shaft. I also made a small piece (hard to see) that mounts to the main die arm and welded a piece of my hydraulic tubing to use as a shaft. My explanation kinda sucks, so I will take some pictures later to show how this actually goes together. Surfice to say, it will measure the angle that the tube is being bent.

I want to thank those who offered input on the Z support for the swingout shaft. Your input there lead to the design of this piece, which was FIRST welded, THEN machined. By machining afterwards, I was able to make the appropriate surfaces parallel without worrying about warpage from welding.



Below: Next I got a start on the hydraulics. I have a formal ISO standard hydraulic schematic that I will put in my final report, but for practical purposes, I made this schematic on my whiteboard to figure out what fittings I needed. This took a long time to plan and depended a lot on what parts were available and what types/sizes of fittings were used on the various components. If you are doing anything like this, I highly suggest you make a schematic and thing very carefully about what adaptors and fittings you will need. My system includes mostly JIC (flare) type fittings, but some components also use SAE (o-ring) and NPT (pipe) fittings.



Below: I mounted the main hydraulic components and installed the appropriate adaptors for them to mate with the hardlines that I will be making. After a couple practice pieces with the flare tool and my previous practice with the bender, I got my first two hardlines bent and flared. Each line uses a sleeve and a nut, which I put on before flaring.



Below: Here is the backside of the picture above. I am glad I made the tree for holding the control valve because it is handy for mounting other components. This gray valve is called a flow divider valve. It's kind of a fancy tee connection in that it splits flow to go to each of the two cylinders. What makes this remarkable is that it uses some very basic fluid mechanics to ensure both cylinders get an equal amount of flow. If you are an engineering type, I recommend you look into how a flow divider works because pretty cool!



There are a lot of hardlines and mounts still to be made. I hope to have the hydraulics working tonight.

How many people are actually reading this? This thread has something like a thousand views. I better stop hitting the refresh button! (just kiddin'!)
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Last edited by TheBandit; 03-02-2006 at 07:13 PM.
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  #45  
Old 03-02-2006, 06:15 PM
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Quote:
Originally Posted by TheBandit
How many people are actually reading this?
I'm check this thread every day! Sure is fun to watch your progress!
Can't wait for a video of it working!

I havn't posted as I had no Tech to add.
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  #46  
Old 03-02-2006, 08:37 PM
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Quote:
Originally Posted by TheBandit
UPDATE
How many people are actually reading this? This thread has something like a thousand views. I better stop hitting the refresh button! (just kiddin'!)
I read every update. I am converting my pro-tools 105 to hydro myself and I find this very informative and interesting. I learn alot from a photo and I thank you for including so many in your posts as they speak volumes to me.

Jay
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  #47  
Old 03-03-2006, 06:09 AM
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Both you guys, thanks for checkin' in. You don't know how much everyone's encouragement means to me. When you guys tell me what I'm doing right and wrong or even just let me know you're watching, it makes me feel like I'm not doing this project alone. It's great to have support!

For those that do keep an eye on this thread, you are going to like this:

http://bender.xtremefabricator.com/BenderTest.wmv

Sometimes there just aren't enough Os or exclaimation points at the end of the word "wahoo!"
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  #48  
Old 03-03-2006, 05:10 PM
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UPDATE

I want to send out a special thanks to Cris at 2020ssi (Bend-Tech) for his contribution to this project. I can't imagine how much of a struggle making these hardlines would have been without his incredible software!

Look forward to a writeup on how I made these lines. For now, here are some pictures to document the results. Some of these lines still need some support (especially where the hoses attach for the cylinders), but I am incredibly happy with how clean everything turned out! It's a shame I'll be boxing all this in where you wont be able to see it.

Below: Most of the components are on the opposite side of the control valve, so I had to route a few lines around 180 degrees using a series of bends.




Below: Looks like the "pipes" screensaver in this picture! Working our way around the control valve, you can see things get a little more involved on the other end.





Below: The flow divider valve and solenoid bypass valve can be seen here. It took a bit of headscratching to decide where things should be positioned.



Below: The final component to the hydraulic system is one of the most important. This liquid filled gage will help me calculate the actual tube bending torque and determine if I am overloading the bender.



The next project is mounting and wiring the control system, which began with the encoder. I still need to find a home for the PLC and put together a bread board for the user interface.
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  #49  
Old 03-03-2006, 08:09 PM
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The light just got a whole lot brighter now didn't it.


Jay
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  #50  
Old 03-03-2006, 10:17 PM
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Quote:
Originally Posted by sapper
The light just got a whole lot brighter now didn't it.


Jay
Not for me, I have no idea whats going on with all that milling equipment. But still trying to get my jaw off the kkkey board.
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  #51  
Old 03-09-2006, 02:13 AM
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haha, thanks guys! I am pretty stoked to have the hydraulics going, but there's a lot left to do before I can run some tubing through this thing!

UPDATE From 3/6

The next project is mounting and wiring the control system, which began with the encoder. I am currently in the process of wiring the PLC and this prototype user interface. Wiring, soldering, and ICs are a mechanical engineer's nightmare. I have always enjoyed my electronics classes, but never had a use for the stuff until now. Here's what I have goin' on:



It's hard to take a picture to show how bright the 7 segment display is. My camera sucks at focusing without the flash. But this will give you an idea.



Here's the mess where I'm at with it. It's a bit involved, but so far things are working fine.



I'll post up some more info on this as I get it working. It should be done by tomorrow for my demonstration!

UPDATE Current

I have no pictures today for you guys, but I am just now recovering from a hell of a week. I spent all night Monday (literally did not sleep for over 24 hours) working on the controller for this project. The goal was to have the measuring and autostop functions working for my mechatronics demonstration. I seemingly ran into disaster after disaster, but managed to get it working fine for the demonstration.

Currently here's how the controller works. The way I have it setup currently, I can only have one display. Normally the display shows you the current bend angle, which is set to zero when you first turn on the machine. When you turn a knob on the control panel, the display will switch from showing the current angle to showing the desired angle, which you are changing by turning the knob. The controller defaults to a desired angle of 90 degrees. When you are done adjusting the desired angle, there is a couple second pause before the display will switch back to showing the current angle.

To zero the current angle, you hold down a button for five seconds and the current angle will be reset to zero degrees.

The controller is always looking to see if your current angle is greater than your desired angle. You can freely move the control valve and the machine will respond as if it were completely manual. But upon reaching your desired angle, the bypass valve stops the machine. A short, but very loud "beep" indicates that you have reached your desired angle. Also, an indicator light turns on to tell you that flow is being bypassed.

While flow is bypassed, you can still use the manual valve to retract the cylinders. They just wont advance. Flow is bypassed for ten seconds, after which point the controller will check to see if you are still at or above your desired angle. If you haven't retracted the cylinders, it will beep again and continue to bypass flow for another ten seconds. If you have retracted the cylinders, the bypass is deactivated and you are free to advance the cylinders again.

There are quite a few more features I will be putting into the controller, including a scheme I have devised for springback compensation. Look forward to more on that as things progress...
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  #52  
Old 03-09-2006, 02:45 AM
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Wow

I am new to the site but have been lurking and just reading hte various threads. All I can say about your bender is WOW! Very impressive. Keep up the good work and be sure to continue to post pic's as your baby gets closer to completion.
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  #53  
Old 03-09-2006, 11:55 PM
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Bandit,
Nice work!!
Questions...Are the lights on your control panel status or mode lights?
and was the encoder specificaly designed to measure degrees?
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  #54  
Old 03-22-2006, 04:42 PM
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Thanks guys for the kind words! I will definitely keep you posted as this machine nears completion.

liketofab, I will have some more info on the controller next week. I will probably post up some video showing how it currently works. The green LED is just to show that the controller has power. The yellow LED comes on whenever flow is being bypassed. If the flow is being bypassed, you can still retract the cylinders, but they will not advance.

Yes the encoder measures rotation, but it doesn't measure degrees persay. The encoder pulses a certain number of times per revolution. Each pulse is basically an on/off voltage. The controller merely counts the number of pulses to determine the angle of rotation. This particular encoder is insanely sensative; it has 12,700 pulses per revolation. This means each pulse corresponds to about 0.028 degrees. This is obviously a lot more precision than you need for a tube bender, but I got this encoder used for a very good price and have decided to use it.

I am going to dumb down the controller a little by making the desired angle accurate to only half a degree. The only reason I have for doing this is I simply don't have enough outputs on the PLC to display more than that. I have also thought about making it only 1 degree accurate, which would free up an output so I could run two seven segment displays instead of just one.

What do you guys think? Do I need half degree accuracy or is it worth sacrificing to 1 degree accuracy in order to have displays for both the desired and current angles?
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  #55  
Old 03-22-2006, 05:19 PM
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1 degree should be fine. I would need to check, but I believe this is the resolution of the Ercolina or Ineco. Most guys who have this machine will not have any way to measure an angle to a half of a degree.
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  #56  
Old 03-22-2006, 05:27 PM
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Thumbs up

I haven't posted on your thread for a while Clint but I have been watching all along. I have to say you are quite a multi-talented guy...machining,welding,hydraulics,electronics and doing an excellent job at all.Good job!! I'm continually impressed!

As for the half degree or one degree issue, I know from experience that a half degree can make a noticable difference when extended out a distance say 36"...or more.But I can also see that it would be nice to have the desired and current readout. Another point to consider is what about the Bend-tech programs...are they calculated in one degree increments or do they show half degrees ( I don't have bend-tech yet ) Like I said before I have bent to the half degree before so for me that would be the way I'd go. Just my opinion
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  #57  
Old 03-22-2006, 05:27 PM
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Man, it's been a long time since I breadboarded a circuit in logic class. Never used it once, but it was quite fun at the time...

Anyway, outstanding work as usual! <bow>
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  #58  
Old 03-22-2006, 05:34 PM
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Quote:
Originally Posted by Captainfab
Another point to consider is what about the Bend-tech programs...are they calculated in one degree increments or do they show half degrees
Bend-Tech EZ & EZ-3D go to the single degree. PRO & SE have settings to go from a whole degree to .001 if you desire.
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  #59  
Old 04-04-2006, 10:40 PM
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Thanks for your feedback on the resolution guys! I am still undecided, but I am going to experiment first to see if I can indeed get two displays going. It's a bit hard to explain how my display drivers work, but I think MAYBE with some creative wiring and programming I can make it happen.

Quote:
Originally Posted by CaptainFab
I haven't posted on your thread for a while Clint but I have been watching all along. I have to say you are quite a multi-talented guy...machining,welding,hydraulics,electronics and doing an excellent job at all.Good job!! I'm continually impressed!
Wow man, what a complement to live up to! Thank you!

UPDATE

A new quarter has started. Finals and spring break are over and it's time to kick things off on the tube bender again. This time around will be the last: I have to have a working product by the end of the quarter. Based on my progress so far, I don't think that should pose too much of a problem.

Last quarter I loaded myself up with 18 units, along with the 15-20hrs a week I spent working on this project. I was going to school at 7am and getting home at midnight on a regular basis. Boy was I beat! This quarter is going to be different. I have ONE 4 unit class, the starts of my master's thesis project, and finishing this project. I should have a lot more time on my hands and I'm not complaining!

First task of the quarter was making the new center sleeve for the main/forming die. I had to run a boring bar down the center of this DOM to allow proper fitment over the main shaft.



The next part to make was the main die drive pin (shown below). This was one of my critical parts to design. Production benders of this type (such as the RMD-150 and Jancy models) use three smaller drive pins that are built into the spindle. On my bender, I wanted to easily adapt Pro Tools dies. In order to do this, I needed to use a similar drive mechanism to the Pro 105. Unlike the Pro 105, however, I do not have the option of supporting this drive pin in double shear. To combat bending stresses, my drive pin is larger and made of 4130. It will be heat treated for significantly increased strength. The increased size requires enlarging of one of the holes in the die, but is necessary to prevent the pin from failing.



Below: I started by facing and turning a length of bar stock to the desired diameter.



Below: I continued peeling away material to expose the proper major diameter for the threads. I used a digital readout while turning this section so that each pass brought me right to the desired shoulder.



There are several ways to make threads. I wish I had time to learn to cut and inspect threads the right way on a lathe, but after talking to a few people I decided it would be too risky and time consuming. I don't think rolling threads would be the right approach for this part either, so I took the easy way out and used a die.

I used the tail stock of the lathe to butt up against the die, keeping it relatively perpendicular to the part. Then I turned the chuck by hand to form the threads. Unfortunately the picture I took of the die on the part didn't come out, but here's a shot showing the threads after they were about 1/3 done.



Below: After I cut the threads as far as I could, I went back with a parting tool and cut a relief near the shoulder. Since it would be impossible to thread all the way up to the shoulder using this method, the relief will allow clearance for the female threads as the part is tightened down.



Below: Here is the nearly completed part.



After I got the part home, I found the threads worked great, but weren't cut far enough into the relief to allow the part to be completely tightened. I'm not sure if there is a such thing as a bottoming die, but if so I am going to look for one to counteract this problem. Some other options would be to chamfer the female threads on the mating part or add more relief to this part. I would like to get as much thread engagement as possible, so I would prefer completing the thread if I can.

Later this week I will cut the hex into the part and hopefully (fingers crossed) do my own heat treating and hardness testing. :)
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  #60  
Old 04-06-2006, 11:00 AM
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Not sure if this would help or not, but a "button" die might help a little. Put it on and reverse it. Do it CAREFULLY though. just a "thought".
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