Results 1 to 10 of 10

Thread: MG Tracer Gantry Salvage

  1. #1
    Registered
    Join Date
    Oct 2007
    Location
    United States
    Posts
    111
    Downloads
    0
    Uploads
    0

    Default MG Tracer Gantry Salvage

    I just bought an older MG electric eye tracer gantry (no table) with four torch stations (two with machine torches in them). My initial plan was to cannibalize (no offense to any practicing forum members) it for the rails, racks, pinion gears etc to build a small homebrew CNC plasma table.

    The machine model is PC750 and has lots of functions I would have never thought of such as the auto-igniter, solenoids for high and low preheat oxygen and fuel gas as well as of course the cutting oxygen for each of the 4 torch stations and each station has a rack and pinion powered height adjustment (not auto, just toggle up/down)- all from the control panel. I plan to keep two torch stations and setup one for oxyaccetylene, the other for plasma and probably sell the other two. They would make a great Z axis since they have guide rails and servo motors already setup with the bearings already in place for the X axis to attach to a piece of .5" x 4" cold rolled flat.

    My salvage plans might be changing. This afternoon I took a few minutes to look it over and dig through the two boxes of parts that came with it and found the control head and cables. I bolted it back on the machine and connected power, and you guessed it- It's Alive... The gearmotors for both axes run smoothly, the four torch heads power up and down and even the auto-igniters buzz (no spark plugs in them). It looks like this 18'-9" beast can be put back into operation with a little work to build a table and just a little more luck.

    My thoughts are now running along the lines of either using a dual operating system, one original, the other CNC using the existing servos and addiing encoders in line with the existing tachs. Either that or figure out a way to interface the electric eye with the new CNC setup, if the eye proves to be fully functional which it seems to be.

    My question is, how does the electric eye work? It lights up and when you hold a momentary switch in the up position the head spins. I drew a thick black line on a piece of paper and it will move the torch heads left or right and when I rotate the paper 90 degrees the other motor (what I would call the Y axis if it was a mill) runs. I guess I'm trying to figure out the actual starting procedure for lining up the torch head with the drawn pattern in order to initiate a cut?

    Similar Threads:
    Attached Thumbnails Attached Thumbnails -large-13-jpg   -large-13b-jpg   -dsc00772-jpg  


  2. #2
    Community Moderator Al_The_Man's Avatar
    Join Date
    Dec 2003
    Location
    Canada
    Posts
    20512
    Downloads
    0
    Uploads
    0

    Default

    There were some of these similar tables that were converted to dual mode, but most users that converted, just went over to almost 100% CNC use.
    The down side, of course to a tracing table is that it takes double the work space.
    Simply, the principle of the trace is that the retro-reflected light back from the table is received by a photo-cell that oscillates, therefore if the reflected image back straddles the line, a sine wave with equal amplitude above and below the zero line is output from the Photo cell, If the head relative to the line moves off course, the sine wave zero reference moves up or down and a correction signal is sent to the servo to maintain the sine zero balance.
    It is alot easier to explain with diagrams.
    Normally a spot light allow the initial lining up of the head, and when the start button is pushed, the auto trace takes over, if a valid line is read.
    The set up of the head is critical, initial hight etc.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  3. #3
    Registered
    Join Date
    May 2003
    Location
    Illinois
    Posts
    323
    Downloads
    0
    Uploads
    0

    Default

    Sir,

    You have a Stewart Warner tracer. It uses photocells and a small motor driving a timing belt to rotate the eye assembly. I believe the output is from a sine-cosine pot yielding DC voltages to go to the servo amps. I think it will run around 60 IPM, depending on the rest of the machine. The scanner has left-right offset capability (kerf compensation). You may be able to get info from MG Cutting Systems. The system worked quite well.
    Likely the motors drove Bison gearboxes; they are good quality. Ther Stewart Warner tracing and drive systems were competitors of ours.

    If you had the instruction manuals for the tracing system it would be a great help!

    Regards,
    Jack C.



  4. #4
    Registered
    Join Date
    Oct 2007
    Location
    United States
    Posts
    111
    Downloads
    0
    Uploads
    0

    Default

    Al,

    You're correct regarding needing twice the space and that's a big drawback for me since in order to get about an 8' x 5' cutting capacity I'll need an area of about 20' x 20' by the time I allow enough room to maneuver a forklift to load it.

    jcc3inc,

    You're also correct, it is a Stewart Warner tracer and controller. The speed also seems to be in about the 60 ipm range. I found a website for MG and sent an email regarding info/ manuals for my machine but haven't had a response yet. I'll give it a couple of days and then call if I don't hear from them. I'm glad to hear you think they are decent machines.

    There's a small broken light (looks like it might have been neon?) on the front of the tracer head. Is it just a power indicator or does it show when the tracer is locked on?


    I tinkered with it a bit more today and blocked up a piece of plywood to hold my pattern about .5" from the tracer head. When the straight line pattern is parallel to the gantry the X drive moves the torch heads and if I slowly rotate it toward the perpendicular of the gantry the Y drive incrementally increases and the X seems decrease in proportion to the Y. I think the machine might just be good to go once I fab a table for it.


    Thank you both for your input.



  5. #5
    Registered
    Join Date
    May 2003
    Location
    Illinois
    Posts
    323
    Downloads
    0
    Uploads
    0

    Default SW electric eye

    Sir,

    If I recall correctly, there was a light on the scanner that indicated off-pattern. Inside there were (3 ???) lights that illuminated the pattern using a dual purpose lens, the outside was to focus the lights, the inside to focus the reflected pattern onto the photocell. Also, the system was likely BOTH a silhouette and line tracer. Somewhere you could elect line or edge (silhouette).

    Where are you located? Again, it would be very desireable to have the schematics and operaotr's manual.

    jccinc at owc dot net

    Regards,
    Jack C.



  6. #6
    Registered
    Join Date
    Nov 2006
    Location
    Scotland
    Posts
    925
    Downloads
    0
    Uploads
    0

    Default

    Apologies for fetching this back from the dead but I`m clutching at straws.
    I`m after more info or a manual on the Stewart Warner LCT 30B scanner system.My total knowledge of them is what I`ve just read on this thread.



  7. #7
    Community Moderator Al_The_Man's Avatar
    Join Date
    Dec 2003
    Location
    Canada
    Posts
    20512
    Downloads
    0
    Uploads
    0

    Default

    Are you looking at reviving the trace cutting system? as they are considered passé now, it may be more economical to convert to CNC rather than pour money into it?
    Burny have an updater for the trace system I believe?
    http://www.directindustry.com/prod/i...57-565723.html
    Al.

    CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  8. #8
    Registered
    Join Date
    Nov 2006
    Location
    Scotland
    Posts
    925
    Downloads
    0
    Uploads
    0

    Default

    Al,at this stage I`m just seeing if it will work.It`s a profile I bought dismantled years ago and was thinking of taking the torch of and adding it to my cnc plasma table.However,we stuck it together the other week and all that appears wrong at this stage is a couple of broken switches which are available from RS.
    That particular system is as you say long gone but over here the biggest supplier of welding/burning equipment sells most profiles with a tracing system in addition to the cnc.
    They think this is because in a jobbing fab shop most guys can burn but not all can programme cnc but they can all do a sketch and use a tracer system.
    They also mentioned that it`s cheaper to buy another table than retrofit a tracer but the link you posted is interesting and I`ll enquire with the Burny agent here.Will be interesting to see what it costs here in relation to there.
    I`m banned from working at the moment so this gives me something to tinker with.



  9. #9
    Registered
    Join Date
    Aug 2008
    Location
    USA
    Posts
    5
    Downloads
    0
    Uploads
    0

    Default

    Yrs ago bought koike table system with westinghouse eye system. Installed computer with mechtronics motion control board (analog output) goes to existing westinghouse drives. Installed gear rack for encoder feedback. Eye died years ago. Use it all the time. Program with old dos version of FAST CAD with a RAY CAM cnc package that runs in FCAD. > Let's me leadin or out where I want it to. (Bobcad also works >have to play with it to get it to do what you want it to do). Mechtronics board is a 3 axis machine controller ( Fanuc 6 G codes> Zaxis locked out) Works for me HSARC



  10. #10
    Registered
    Join Date
    Jan 2008
    Location
    USA
    Posts
    2030
    Downloads
    0
    Uploads
    0

    Default

    What most do to upgrade the technology on the old photocel tracers is to install a newer technology cnc control (Hypertherm Automation or Burny).....often the cantlever end of the machine is cut off.....the table that sits under the photo-cell is removed and a cutting slat bed is placed in that area. No you have a more conventional gentry style machine.

    You will still have isues however, as the drives and motors generally are only stable for up to about 40 inches per minute...even with cnc control. Of course all of that can be upgraded to newer technology as well!

    Jim Colt Hypertherm



    Quote Originally Posted by hybidder View Post
    I just bought an older MG electric eye tracer gantry (no table) with four torch stations (two with machine torches in them). My initial plan was to cannibalize (no offense to any practicing forum members) it for the rails, racks, pinion gears etc to build a small homebrew CNC plasma table.

    The machine model is PC750 and has lots of functions I would have never thought of such as the auto-igniter, solenoids for high and low preheat oxygen and fuel gas as well as of course the cutting oxygen for each of the 4 torch stations and each station has a rack and pinion powered height adjustment (not auto, just toggle up/down)- all from the control panel. I plan to keep two torch stations and setup one for oxyaccetylene, the other for plasma and probably sell the other two. They would make a great Z axis since they have guide rails and servo motors already setup with the bearings already in place for the X axis to attach to a piece of .5" x 4" cold rolled flat.

    My salvage plans might be changing. This afternoon I took a few minutes to look it over and dig through the two boxes of parts that came with it and found the control head and cables. I bolted it back on the machine and connected power, and you guessed it- It's Alive... The gearmotors for both axes run smoothly, the four torch heads power up and down and even the auto-igniters buzz (no spark plugs in them). It looks like this 18'-9" beast can be put back into operation with a little work to build a table and just a little more luck.

    My thoughts are now running along the lines of either using a dual operating system, one original, the other CNC using the existing servos and addiing encoders in line with the existing tachs. Either that or figure out a way to interface the electric eye with the new CNC setup, if the eye proves to be fully functional which it seems to be.

    My question is, how does the electric eye work? It lights up and when you hold a momentary switch in the up position the head spins. I drew a thick black line on a piece of paper and it will move the torch heads left or right and when I rotate the paper 90 degrees the other motor (what I would call the Y axis if it was a mill) runs. I guess I'm trying to figure out the actual starting procedure for lining up the torch head with the drawn pattern in order to initiate a cut?




Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum from DIY CNC Machines to the Cad/Cam software to run them. The site is 100% free to join and use, so join today!

Follow us on

Facebook Dribbble RSS Feed