Screwing strategy for SCARA robot

    Dear Colleagues,

    I will be involve in a project, where FANUC robot SR-6iA (30 kg) will be used.

    On the robot wrist, automatic screw feeder and screwdriver (most probably supplied by Atlas Copco) will be installed.

    My question related to movement strategy to be used for screwing the screws.

    The movement speed of the robot arm at the stage of screwing, obviously will be calculated by the step of the screw thread. Is that correct?

    The number of threads and the step will give the total movement length. The number of turns (the turns will be set into the software/controls system of the screwdriver) will give the speed (mm/s).

    One of the thing, which bothers me is the start of screwing stage and the screwing stage itself. At the begging, when the screwdriver is started, the move down must be slow, and next, when the screwdriver reach nominal revolutions, the move down should be increased - this is my understanding.

    Should this robot movement must be determined on trial and error approach?

    Or probably I too complicate the task?

    Can you share your experience for such screwing projects?

    And advices will be highly appreciated!

    Reagrds,

    Svetozar Yolov

    The nut runner should have spring tension.. all you need to do position wise is center screw come down to supply enough tension for screwing and the atlas copco program will do the rest... Reverse turn start... run down.. max torque... wait for signal and poof.. you are on your way.

    Before you dig any deeper into this application, make sure that the selected robot can handle the moment that this screwing application will mean.

    I would check wit the local FANUC rep if this is feasible or not before going further.

    Ideally you would want some kind of force feedback to determine your feedrate of the robot. Otherwise it will probably be a case of trial and error.

    Agree with ND Auto. I've done an application like this before, although it was with a Vizumatic driver.

    All you should have to do is program the point and tell the screw runner you are in position.

    That arm should be more than capable for a screw driving application.

    Check out the Fanuc position converter I wrote here! Now open source!

    Check out my example Fanuc Ethernet/IP Explicit Messaging program here!

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