Tool Definition error too high

    Hi,

    I am trying to define a tool to calibrate bases. every time I try to define the tool I get about 0.3mm error. The operation I want to do is really precise, A deviation about 0.2mm is already a failure in the operation.

    The problem:

    I try to define a base an readjust the angles A,B,C to make it parallel.

    Then I check with another pin, or the gripper I want to use, the base definition is not parallel to the real base.

    How can I make the initial tool definition more precise. I am using XYZ-4 Point method with 2 metal pins I machined to a sharp point?


    Thank you already

  • HawkME October 17, 2023 at 12:06 PM

    Approved the thread.

    Make sure that:

    Robot is ok and without backlash

    Robot is mastered

    Tool is mounted correctly ( no slipping or flexing)

    Load is correct

    Tcp is close to the center of the flange. If it is far, it will never be precise enough. Up to 200mm is ok, but beyond that is asking for trouble

    Make sure that reference pin is not moving or flexing. If it gets touched you need to start over.

    Or just neasure it with CMM

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

    0.3mm is getting close to the limits the robot can achieve. Is this an Absolute or High Accuracy robot? What model of robot? Is the payload data set correctly? Was the Load Mastering carried out correctly?

    In the end, there are just limits to how well the teachable methods can work. You can probably squeeze out a bit more precision by using programmed motions rather than jogging, observing drift while rotating around each TCP axis by ~90deg, and tweaking the XYZ values after each test.

    You will reach a point where improving the precision on one axis of the TCP introduces more error on the other two axes. At that point, you've hit the limit of what can be achieved with your robot. If you can tolerate more error on one axis than the other two, you can squeeze a bit more out by letting the "sacrificial" axis drift while fine-tuning the other two as much as possible.

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