Need Help!- How to retrofit a press brake

[tisoykid]

I am a mechanical engineering student and for my senior capstone project some fellow students and I are trying to retrofit a press brake. We are on a tight budget and we are trying to do an update. The main scope of this project is to put some kind of input so that the backstop will go back and forward, that is it. Any kind of help or advice would be greatly appreciated.

[Al_The_Man]

What system is on there presently?
Is it just 1 axis, i.e. back gauge?
It is not that simple as going 'back and forward' as it is commonly servo driven and feedback either via encoder or linear scale.
It depends on what you already have on there as to what you might be able to reuse.
Al.

[Fabio1]

Yes, please elaborate.....details or pics.

[will gilmore]

watch this YouTube - Homebuilt CNC press brake Mach3

[will gilmore]

oops sorry this is the one that shows the cnc back gauge

[Fabio1]

So are u hoping to creat a program to crimp bend an arc in a sheet?

[tisoykid]

The press brake which is currently in our shop is a Piranha 1157 and I believe that it is a 65 ton brake. Currently there is not a back stop on the machine. So, unfortunately there really is nothing for us to reuse. At the moment we just want a one axis with the back stop going forward and backward with some kind of input. I will get some pics of the brake asap so that you will be able to see exactly what kind of press brake we have and what we have to work with.

[Al_The_Man]

Well as someone who as retrofitted back gauges for a living, you will need a fairly extensive degree of mechanical additions as well as electrical/electronic.
Not a good choice on a tight budget.
I would recommend, if possible, checking out any existing press brakes to get an idea what you are up against.
Al.

[tisoykid]

We have looked at a couple of different press brakes and have an idea of what we are up against. From your experience what would be a reasonable price be to retrofit a press brake that does not have anything?

[Al_The_Man]

Well an off the shelf packages that I have used in the past include Automec,
http://www.automec.com/stimuluspackage.htm
which currently have a sale on their 2 axis systems for around $11,700.00, not including fitting.
To do it on a shoe string, then the majority of electronic parts can be bought on ebay, a source of mechanical parts is local machinery auctions where some machines that do not sell end up for scrap, so these could be a source for mechanical parts.
One machine had one method that may prove to be economical for moving the gauge used a rolling ring straight shaft mechanism with a DC motor on the end of the shaft.
The only thing is you need a relatively high cost linear scale instead of a cheaper encoder on the motor.
If you can scrounge mechanical parts and have a machine shop handy, you should be able to fabricate the mechanical frame.
Al.

[tisoykid]

One thing we were wondering if we were to build the back stop our selves what is the hard ware that we will need. I watched the video of the home built press brake which was awesome!! Seriously!! I saw that the guy was running Mach3 software which looks very handy. At the moment all we need is a one axis. Just back and forward. None of us are very familiar with the hard ware so that the computer can talk to electronics. Some of the stuff we know we will need is a PLC, and some servo motors or stepper motors. Which kind of electric motors would be better? What other kind of hardware will we need in order to make this work? Any input would greatly be appreciated.

[Al_The_Man]

I would use a DC motor and encoder, they can be picked up relatively easy on ebay etc, you will also need a motor drive or amplifier.
The type of drive control, whether step/dir or analogue depends on the controller used, Mach using step/dir may be one solution but is a bit of overkill for just point to point positioning, if going with a PLC you should not need a PC as in the link.
Most PLC's have a analogue motor control module and some sort of operator interface to enter data and read back position.
The back gauge usually steps to the next programmed position when a limit switch is tripped at the top of the return stroke.
You also need home limit and overtravel limit switches.
For the mechanics you need some way of transporting the gauge back and forth such as a ball screw or rolling ring method I mentioned earlier, the gauge would run on slides or guides of some kind, these are the most common methods for any kind of accuracy.
Al.