My dust collection system has a rigid pvc pipe and a flex hose with a steel wire inside it. I wrapped bare copper wire around the rigid pipe and anchored it to the pipe with a sheet metal screw. This is the wire:
I ran a wire from the wire that is inside the flex hose to that sheet metal screw, too. The other end of the copper wire is connected to plug with all but the ground terminal cut off. I plug that into the power bar that is powering the controller and my router. That power bar is grounded normally.
I had frequent issues with UGS and the Mill before I grounded everything this way. I’ve had no problems since.