grease and effects of not greasing regularly

  • my work has some R-2000ia 165f machines we are implementing into production. the most resent one had a srvo-050 collision detection alarm that would go off upon trying to move the robot. we looked into a bunch of causes after i researched what could trigger that alarm. i inquired to my head of maintenance about the last time this machine was greased? too much or too little isn't good. he said it's good to go, all PM's were done. he has all the proper documentation to know how and when this stuff should be done. one of his guys pulled the plug by axis 6 servo to check levels and got blasted with grease. its was his understanding that it shouldn't be under that much pressure? now it doesn't trigger that alarm anymore. does that sound like an improper PM? too much grease?


    my main question is if you didn't stick to the PM schedule properly what could that damage? obviously the components of that axis but what else? Could that effect the points in my programs?


    any info is ammo for me to make sure they stay on top of this and properly.

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  • After greasing an axis, jog the axis back & forth until grease stops coming out of the outlet, then put the outlet plug/bolt in. Allows pressure built up near the inlet to dissipate. Only adds a couple of minutes to the PM time and well worth it.

  • today our maintenance guy decided to swap out j6 servo with one from another robot we haven't done anything with yet. the one we get the g1,a6 collision alarm on was used a little this morning to troubleshoot some things, barely moved around. any thoughts on these pictures of the grease inside where j6 servo is? anything look abnormal or should be a concern?

  • The axis J4,5.6 gearbox look like it had the correct amount of grease but it doesn't quite look like Molywhite RE.00 or the Vigogrease RE0. The excessive pressure you had described earlier could have forced grease into the J6 motor and is causing the J6 collision error.

    The gearbox cavity of the used robot looks like it was not pm'd and the grease has dried up quite a bit where it hasn't been mixing during movement. I would still try the motor from this robot in your current one.

    Hint: Bring axis J3 down as close to vertical (-90) as possible to eliminate grease loss during upper arm motor changes.

  • we got the j6 servo swapped in and the error code hasn't happened yet. maintenance is now aware what the inside looks like when they sit and will PM it before use. these are new for all of use here so we weren't sure what was normal, acceptable or not good lookin. thanks for the continued help guys.

  • Your other robot looks alright due to it having been stationary.
    The one you've been using has had the grease go liquid from heat and mechanical work. It's very clean grease too, so no real issues inside. Normally when we did maintenance for bad reducers / motors we'd get blasted by pitch black grease.


    As someone else pointed out, jog the robot after greasing, without putting in the plug. That way you won't get pressure build up inside.


    The only way your program points could be affected by improper PM is if:

    1. The maintenance guys manage to demaster the robot, in which case you'll need mastering and, likely, touch up some positions.
    2. Your reducer goes bye bye, in which case you'll need to swap it out and, again, remaster the robot.


    Just simply over greasing won't "push" the points away, just annoy whoever opens the plug the next time. Or, as in your case, a collision detection alarm.

    • Helpful

    From my past experience -

    Write a quick "grease work in" program to run in T1 during the greasing process. Make sure you move all of the joints the recommended amounts from the manual, I usually run this program at 100% of T1 speed for about 5 minutes. Put the caps in.


    Another (dumb) question - is your payload set correctly on the robot? You'll get collision detect alarms all day long if you have nothing on the wrist and your robot thinks it should have 165 KG of payload (the default from the factory is 100% of it's rating). If you can't get the payload info perfectly from SolidWorks or a calculator, weigh it at least or best guess at least. I worked at an automotive manufacturer as a Robot Maintenance specialist and maintenance supervisor. After we changed one of the car lines over to a new model, one of our biggest robots (M900iA-600L) kept giving us collision detect alarms. So to temporarily make it through to the end of shift we bumped the sensitivity down. Then we re-ran the "automatic payload calculator" between shifts, and found out the Payload Info was off by about 75 KG, and the center of mass was off by about 300mm. Once that was done, set the sensitivity back to normal, no more issues.

  • From my past experience -

    Write a quick "grease work in" program to run in T1 during the greasing process. Make sure you move all of the joints the recommended amounts from the manual, I usually run this program at 100% of T1 speed for about 5 minutes. Put the caps in.


    Another (dumb) question - is your payload set correctly on the robot? You'll get collision detect alarms all day long if you have nothing on the wrist and your robot thinks it should have 165 KG of payload (the default from the factory is 100% of it's rating). If you can't get the payload info perfectly from SolidWorks or a calculator, weigh it at least or best guess at least. I worked at an automotive manufacturer as a Robot Maintenance specialist and maintenance supervisor. After we changed one of the car lines over to a new model, one of our biggest robots (M900iA-600L) kept giving us collision detect alarms. So to temporarily make it through to the end of shift we bumped the sensitivity down. Then we re-ran the "automatic payload calculator" between shifts, and found out the Payload Info was off by about 75 KG, and the center of mass was off by about 300mm. Once that was done, set the sensitivity back to normal, no more issues.

    I like that grease program idea, sounds easier than manually moving the joints the way it's specified in the maintenance procedure.


    we ended up swapping j6 servo and mastering it, no more collision alarm. thanks for the useful information on payload settings.

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