The lack of rigidity can be compensated for by using sufficient amounts of complicated math One of my friends from the university did some research on that while he was taking his Phd. As far as I remember, he ended up milling in hard materials (steel?) with a KR120. As far as I remember, the tolerances were within 1/10 of a mm. They made their own calibration of the robot using some advanced optical rig. Impressive stuff.
Hai. Sorry for distributing your festival holiday. I doing robot milling using KR120 HA. I interested to know your friend Phd and possible to link me to him. My email addie@innopeak.com