Fanuc M-710iC maintenance - grease replacement in joints

    Hi! I'm replacing the grease in all joints of a M-710iC and have some concerns.

    The robot itself is mounted upside-down to a ceiling rail (external axis), which raises these questions for me:

    - Does the mounting orientation affect the replacement of grease in any way?

    - After replacement of grease, according to the Operating manual chapter 7.2.6. the robot is supposed to be moved with grease inlet and grease outlet uncapped to release residual pressure.

    When doing so, large amounts of grease are expelled from the vent hole of joint 1. If the robot was "normally" floor mounted, the vent hole would be the highest point of the joint and not much grease would escape I guess.

    Has anyone encountered this before? What are your thoughts about this?

    Welcome Kevster. It's a shame Fanuc does not address the any changes needed in the PM procedures regarding different mounting angles. Fanuc tech support may be to give official guidance not included in the manuals.

    While I have never used the containment bags they specify, they may provide a vacuum break that prevents air from reentering the cavity that displaces the grease and allows it to flow out. I always wondered if the bag setup came with instructions stating to make sure the air was expelled from the bags before they were installed.

    For me, I jog the axis, plug any holes that are 'sucking air' and then jog back and forth across the range until it quits pushing grease out for a whole back/forth cycle. That back and forth is usually between 2 & 5 times, sometimes more on a few occasions.

    The first time I read those procedures when they came out with them years ago, I felt they were dictated by lawyers, not common sense, to address grease cavity issues due to exhaust ports too small (6mm), grease that easily thinned (Molywhite), inadequate front motor seals, and the prevailing use of high pressure devices to deliver low pressure volume (grease guns & pumps). For the most part, they have addressed these issues by enlarging exhaust ports, change of grease to Vigogrease and stating cavity pressure maximums. I feel the procedures for releasing pressure are still in need of updating and expanding to cover situations like yours.

    Hey Skooter, thank you for your reply! I totally agree, as is it is not uncommon to ceiling mount robots.

    I did not use the bags at all, which now that I think about it, would maybe prevent the large amounts of grease being expelled. On Friday before leaving work I bored a 6mm hole through a spare M12 bolt which I screwed into the vent before running my "pressure release program". This time only a "normal" amount of grease were expelled from the now smaller vent, no excessive amounts were slinged out. By common sense I feel that the specified procedure for pressure release are quite exaggerated.

    My program runs all joints back and forth in a 90deg range at 50% OVR 25 times. That should be more than enough to move the grease around the gearbox and expell trapped air from the grease bath.

    The instructions were quite overwhelming at first, and the thought of hand pumping these amounts of grease gave me the chills, as we have six of these robots. I instead decided to fit a pneumatic barrel pump with a pressure gauge at the outlet and a pressure regulator to control the strokes of the pump. This were a bit tedious for a few joints, but overall it worked quite well.

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