Our Dobot makes plastic grinding sound when moving within from -45 degrees to +45 degrees.
The friction is bad enough to make it inacurate.
It is not from the cables, it seems to come from front side under the arm.
Also the plane of joint1 is not firmly horizontal, but can be tilted opening a gap on the back - see pictures.
That affects the grinding.
It can not be tilted from the top.
It feels as if the motor for joint1 is not reliably attached and can be tilted within the base.
What can we do?
We are comfortable with both mechanical and electronic operations.