I wanted to share some updates on my robot "drift" issue, after 2 more months of running parts in the cell the robot in fact moved again, this time 1.5mm in X+ and Y+ when compated to a programmed point in the cell that was being used to check for this. Also the robots joints, J1, J2 and it appears J3 have moved away from the original pre-calibrated whitness mark locations.
So I re-masterd the robot the the quick master ref position fixture we created, as recomended by tech support, however, that did not work. I believe it was becuase in order for quick master to work the encoders need to be outside of 0.2* degrees, so it was not accurate enough for our applications. After re-calling tech support the do not think that re-master is the way becuase it does not address the root cuase, it was simply something to try that could maybe work as a bandaid untill the real issue is fixed.
With that being said tech support also did not think using iRvision to re-teach frames or to re-master is a good fix (not sure if iRvision re-masters, only calibrates?) . They said if we were to re-master the robot to the Fanuc fixture every 2 months that would probalby work by resetting all the points, however, it would not be easy and makes almost no sense to do. They believe there is a mechanicle issue, as you guys were thinking.
They instructed me to check the crash logs and do some other things to look for damage. I was not able to feel vibrations or notice backlash, however, each one of our robots logged on average 625 crashes since they were installed about 2 years ago. Also only one payload schedule when we should have more, and our robot sensitivity is at 100% when they recommend trying to get it to 150-200% to reduce damage when a crash occurs.
I am planning on having a service engineer come out ot do PM on these robots, they have not been done in 3 years. While they are here, I will ask them to check if there are mechanicle issues, I was told they may see metal chips when re-greasing the joints.
With all this being said, I am working on touching up all of our robot programs (8 Cells). If Fanuc does deem a gearbox reducer issue or something like that and we do have then change out the components, will I have to re-program all of the cells or would they simply copy and re-load the encoder values.
Thanks again this forum has such a great help, you guys are wonderful