Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: KE5AFU on March 20, 2010, 12:04:07 PM
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Hello all,
I have a Cincinnati Sabre 750 running an Acramatic 850 control. The hardware is in great shape, and if you know how to talk to the original control it does a good job machining, still has tight tolerances, etc.
However, I can't interface with it easily and still trying to figure out the DNC to drip feed due to lack of space. Also the computer is a time bomb, the slightest thing that goes out can and will cost an arm and a leg.
So, I'm looking to retrofit with something more modern. I was looking at the Centroid systems, but I've been reading lots of negative about Customer Service and bugs lately, someone had mentioned Mach 3 so I though I would stop by and see i anyone
has any experience with converting a large VMC to Mach 3 or if it is more a hobby style controller.
Thanks in advance,
- Matt
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so I though I would stop by and see i anyone
has any experience with converting a large VMC to Mach 3 or if it is more a hobby style controller
Dont have a VMC but have done a Bridgeport series 1 CNC, a Beaver NC5 mill (Bigger than the Bridgeport) and a Computurn 290 Lathe which is quite a big machine, (about 3000KG with 21 inch swing)
Mach is very adaptable and there is not much that you cant do with it.
Hood
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My main questions will be interfacing with the servos, spindle and tool changer. Servos are Red Cap Fanuc, spindle is an AC drive Fanuc servo. Yes, this one is a heavy machine, about 9,000 pounds of iron.
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As the servo drives will likely be analogue input you would need to use something like the DSPMC or KFlop to convert the Step/Dir signals to analogue.
My Lathe has a 6 position rear turret and a four position front toolpost (have another 6 pos turret that will replace the toolpost one day LOL ) I interface the turret/toolpost via a PLC over Modbus.
Hood
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The approach I've seen used adapting Mach to a machine with a tool changer and complex spindle control is to use a separate PLC controller to control the tool changer and the spindle, and have Mach just send commands to the PLC.
These guys sell reasonably priced PLC's:
http://www.automationdirect.com/adc/Home/Home;jsessionid=5e30595775d256d52290722859345d5b7367
I'd also take a look at the Modbus based I/O expander available from Peter Homann, it may have enough capability to control the tool changer:
http://www.homanndesigns.com/Products.html
Good luck-
Paul T.
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Hmm, well I've got a plc and a couple expansion boards for it from a previous project that I guess I could use. 255 inputs and outputs will all the expansions.
I've got to get much more familiar with everything before I start tearing into a working (for now) cnc machine. Any suggestions on where to read up on interfacing in general for a VMC?
Thanks all
Matt
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Your PLC will need to have ModBUS.
Cant really point you to a specific place for interfacing as it will really depend what you have. If you can find out whether your drives are +-10v analogue command only or if they are capable of Step/Dir that would be a start.
Hood
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Ok, I'll do some checking on the model #'s and post back up.
Thanks for the help
- Matt
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Greetings KEFAFU:
I am retrofitting one of my early 1980's 4-axis mills, using the Vital Systems DSPMC controller. They (Vital Systems) worked with Art developing the firmware to run with Mach3. The manual and related software AxisWorks (motor tuning, PID graphical interface) is very well written, and thorough. The controller interfaces with the PC through an Ethernet crossover cable.
The old proprietary controls are not worth spending the money to repair; (1) Parts are hard to find, (2) the circuit boards costly if you can even get them, (3) they are really ancient technology, (4) the controls are filled with zillions of wires that have become frayed, insulation in doubt, and generally a nightmare to figure out, (5) even if you could get the original schematics and prints. which more often you cannot, (6) the screen is an obsolete, bulky CRT, with a crappy visual look, (7) and a nice color touchscreen is out of the question! (8) and the lack of memory was a joke, and the "drip-feed" involved special boards and connections.
The PC, and the evolution of electronic micro-circuitry has revolutionized the machine tool industry. The big, corporate proprietary controls are all gone bye bye, along with their super costly maintainence and ridiculously expensive parts. Good riddance!!
Mach3 is a constantly evolving control interface, with the very writers often on this forum answering questions, and helping to make the solutions. Mach v.4 is in the near future, and the network of professional users/experts/ worldwide is the icing on the cake.
Regards,
John
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Hi Matt,
I am about to undertake the same conversion on a sabre 750 with 850sx controller. I would really like to hear how it went and with which hardware you have decided to replace the outdated cincinnati equipment.
SK
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Things have moved quite fast in the last few years with Mach and external controllers and there are now quite a few controllers that can control analogue command servo drives so you may wish to look at them.
I have used one of them on my Chiron retrofit and it is the best controller I have used to date, its the CSMIO/IP-A from CS-Lab.
http://www.youtube.com/watch?v=JS9mh_iMing
Hood
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thanks for reply Hood,
I have looked at even changing the encoders on the red cap Fanucs that come standard on the cin sabre 750 but that is getting to be a bit too much really.
My issue is that the controller is on its way out (works when it wants to) and replacing it would be in my opinion a mistake as I have had enough of standing at that Q!"$ยงยง$ console typing in gcode. I would like to be able to use mach3 (by the time I am ready Mach4 should be out!!!) to run the machine due to its wide support and versatility. What I do want to avoid though is loosing accuracy and speed. From what I have seen with other machines is that they are quite slow until I watch your link. That is really the first machine that I have seen of that size powered by mach3.
I have a post of the build on cnczone, would be great if I could pick your brain along the way!!
Sourkraut
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You shouldnt lose accuracy or speed if you use the original motors/drives (if possible) or use modern equivalents.
All my machines I have kept to about the rapids that they were originally, well except the big lathe, it was originally 5m/min I think and I run it at 10m/min. The Beaver Mill was originally 8m/min and Chiron 20m/min and I have kept them both at these speeds.
Years ago things were limited to the max pulsrate of the parallel port but the SmoothStepper etc changed that as far as Step/Dir was concerned and recently there have been other controllers that can drive analogue command amplifiers/drives and that is what I am using on the Chiron. I will likely switch the Computurn lathe over to that method as well in the future.
Hood