Question, electrical noise interfering with stepper moter operations

Hi, I built a DYI CNC router and everything works great until I turn on the router. That is I can run cnc programs and they run great with the router motor not running. I turn on the router motor and the run program or just movement with jog and the movement will pause over and over again until the controller locks up and I have to disconnect the USB connection. I reset the USB connection and it works again. The wiring to the router motor is shielded but the stepper motor wiring is not. Any thoughts??



nvcm6v2.1 usb controller, nema 23 motors

What is the nature of the router motor?
Have you followed recommended earth grounding techniques, including bonding any moving mechanisms such as a moving gantry etc