Non Linear motion in world

  • We have a gantry Fanuc that removes parts from an injection molding machine. Its a used robot and the markings for mastering it are mostly missing.


    Here is the problem: It won't move in a linear motion in the world cord system. If you move in the Z(+/-) it wants to rotate on joint 6 while moving up or down. So we have to put in extra points to compensate. Also when you move in the X(+/) it wants to bend at joint 5 while moving. It just can't hold the EOAT in a linear path.


    Our theories so far are that some of the mastering marks are 90 degrees out from the originals, or that the servo motors in some of the joints are incorrect for that model of robot and they receive pulse encoder data differently.


    Any help would be appreciated. Its getting irritating to set up nipper cuts with a nonlinear robot.

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  • Hi
    Trowathegodofdeath



    Welcome to the robot-forum


    Was the robot running ok "before" or you just bought it and put it to work ?


    I had a similar situation (my mistake) when I loaded the wrong core software. I think it was from a 710 to a 2000.

    Retired but still helping

  • You can check your software in menu, next, status, version id. You could check mastering data and compare it with the data that should physically be present in the controller.
    Under menu, setup, frames, other, jog frame, you can see if your jog frame has been modified, it should all be 0,0,0.
    Have you moved the robot to its zero position? All axis to 0. You should measure 1550mm from the center of the axis6 flange straight to the floor. That could be an indication.

  • Its an M-710iB and thats what software is on it.
    The jog frame is set at zero.
    We just remastered it to zero last weekend, but that didn't fixit.
    The zero markings are mostly missing and you either have a scratch or a drawn line to go by.


    Thanks for your suggestions.


    Could it be the wrong set of servo motors for that model?
    Or maybe the ones showing in the software are not the ones physically installed??

  • I suffered the same problem when I worked with a robot with the wrong core installed, how munos said have you checked than the firmware version is right?


    Inviato dal mio MotoA953 con Tapatalk 2

  • I agree, sounds like the wrong core software is installed and the kinematics are being calculated for a different mechanical arm. I would bet that no other servo would work except for the correct one. Did you get a memory card with the robot ? Looks slightly larger than a credit card.

  • I checked the firmware on the 710iB and the cart. mot. parameter and joint mot. Parameter have asterisks in the ID column.
    We have an M-16iB that has V3.00 instead of asterisks .


    So how would i go about updating those IDs. I doubt we have the memory card to it.

  • I don't have a robot in front of me to check this, can someone else please elaborate on what Im about to tell this person..


    I hope I am mostly correct here as its been awhile. Its not an OS version exacty, its a library that gets installed to tell the controller what arm is connected. I believe its somewhere in the CNTR START , OPTIONS or LIBRARY menu, then MANUAL. During the subsequent menus, it will show the 710 arm library.
    Sorry, with I had more at the moment.

  • I have a feeling you have an issue with mastering... Is this a top loader or side slung robot? The mastering positions for the major axis are different between the two.... If the wrist is doing funky thinks start there with the mastering. To check the wrist...



    Two Pointers, One Fixed, One as close to X/Y zero on the faceplate as possible.
    Teach a point with axis 4 and 6 at zero, axis 5 bent down to meet up the two pointers.
    Teach a second point in the same position, go into point data change the NUT to a FUT


    Jog the robot up and away from the pointer
    Step the robot to the now modified second point


    If the pointers line up as they did at point one your minor axis mastering is good.
    If the point is off, move only one axis to line up the points, single axis master half the amount you needed to move.


    Rinse and repeat, to check your work...



    Have fun... these ones are fun :toothy9:

  • It is a side slung gantry robot above a plastic injection molding machine.


    I'll try the robot library thing first since the press has to run.


    And then we'll try the mastering thing.


    Thanks guys.

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