I had a customer call reporting that their robot [LR Mate 200iD/7L] was malfunctioning. J3 was limp. We soon had the robot disassembled to find that the reducer had internally sheared. (Photos attached). The robot's been in service just over a year. No visible damage externally. Reducer was well-lubricated and had clean grease. No visible wear on the gearing.
I have a strong feeling I know what happened here, but just wanted to get some 3rd-party opinions before I start pointing fingers.
Hint... this robot tends an injection mold.