what you are referring to is known as axis range limitation. it is a cam in a form of a ring and couple of switches. this should make no noise at all, definitely no crunching.
under? that sounds strange, don't think i saw such arrangement before. you can chec working range limitation documentation for your robot. normally the black skirt is used to keep robot cables clean and lubricated. nothing else is supposed to be there but i have found random items (bolts etc) that somehow found their way in. anything foreign will cause cable harness to be damaged.
to fix the problem you need to identify it. if this is under skirt, you need to remove it, use gloves (lube can be dangerous, read MSDS), pull out the cable harness, remove any debris and wipe everything clean, inspect for wear and damage, if ok apply new grease and put it all back.
Hi Ravo
You probably have a range limit on your robot.
We had a KR-30 with this, max 50 and -50 degr on A1.
This ring moves with the end stops and makes a ticking noise. (its inside the black skirt)
Rick
