How would you control a CNC mandrel bender?

[panozeng]

Ok, I have an older mandrel bender that has been updated with an Automation Direct / Koyo PLC but it is still a manual machine. The bend angle is not electronically measured or controlled; instead it uses a mechanically adjustable stop and limit switch to stop the machine at the desired bend angle. It is VERY obnoxious to get this dialed in - I want digital control. The machine still uses a control panel from the 60's with industrial type switches as well - most of which have very dirty contacts and can be intermittant.

I would like to upgrade the machine in 2 phases:

1. Add a rotary encoder and some form of digital angle display that could toggle between the current bend angle of the machine and an adjustable set point. (Or have 2 displays, one for current angle and oe for setpoint) I am thinking about trying to do this part with the PLC that is already on there - but the high speed counter alone is around $300 to read the encoder, which is another $90 - not to mention a display unit at $135 and some rather expensive software to program it (and I would have to learn how!)

2. I plan on adding a tube positioner with stepper or servo control. This would be 2 axis - one for tube rotation and one for linear position. I would really like to have a desktop computer controlling things at this point so it would be easy to program. When bending you position the tube in the 2 axes I just mentioned then bend to a certain angle and do it all again.

I can handle all the mechanical parts no problem, but am struggling with what way to go as far as computer controls and software. Everything I've seen so far on this website is for XYZ control and doesn't really translate well to benders. Also, the machine has a BUNCH of solenoids that need to be operated by the controls - I believe there are about 16 limit switch inputs and 12 solenoid outputs on the current PLC being used.

I would like to hear ideas on how to control this beast. By the way, it is capable of bending up to 6" OD steel tubing - so it is a beast!

Thank you,
Jason

[turmite]

Jason my first question is do you do engineering for Panoz Auto?

Even though the controllers are xyz, and in the case of Mach3 xyzabc ,you can still control your bender with a pc type controller. Now the how to might be beyond my ability to help you immediately but there is a lot of knowledge here. In fact a cnc tubing bender, is something I was wanting to do later down the road.......car design in my blood! That's the reason I ask you the first question!

There are several controllers that would work but I personally use Mach2/3 from Artsoft, an advertizer here on the Zone. They currenly have over 5000 members on their Yahoo and over 1000 on their Machsupport forum. Then you have the Artsoft forum here on the Zone that is quite a good one too. The product is great but the support is more than world class.

Mike

[Al_The_Man]

Originally Posted by panozeng I would like to hear ideas on how to control this beast. By the way, it is capable of bending up to 6" OD steel tubing - so it is a beast!

It can be done by PLC as you have found out, but does require some engineering.
For those specifications, I would say $500 is quite reasonable, but if the the expected return on investment is not going to support spending that then it may not be worth the effort.
Industrial Tube benders like Pines, are many thousands of $$$'s.
My 2¢.
Al.

[panozeng]

Yep, I know how expensive the Pines benders and associated controllers cost. This machine was custom built many years ago by a tube bending engineer that worked with Pines machines and is loosely based on a Pines #3 bender with some nice power boosting upgrades. It was intended to bend 4" stainless tubing on 1D (4") bend radii, and I fully plan on testing that since I got tooling with it up to 4".

I guess I just think of the PLC stuff as being close but not as nice as computer controlled. I have been searchingon here, and I see a few posts where people suggest using Mach 2/3 for benders. I guess I will look into that option. I can always leave the current PLC on there and have the computer control it - that way I could run it with or without full computer control...

Yes, I am one of the engineers with Panoz Auto - in the street car division. I have been there just a couple of months short of 10 years now. I have also started a shop of my own doing mandrel tube bending and fabrication, and this bender is located there.

Thanks,
Jason

[Al_The_Man]

I retro-fitted an older Pines bender for a customer of mine who didn't want to spend that much, I used a Galil motion controller and a proportional servo valve, both off ebay, the machine already had hydraulics, this way I programed slow down at end of bend and spring back allowance.
IMO it would pay to keep the PLC just for the machine control of solenoids etc.
Al.