[BrendonV]

Hi everyone. Can anyone help? I bought a CNC 3040T Chinese ebay special. I am having a problem with the z axis. It all works well but i realise when i run the spindle motor the z axis stepper ticks and rises very slowly. Even when no programs are running. This means when i run a tool path by the time the routing is finished the z axis could have risen by at least 3 mm. This isnt any good when your trying to engrave plastic sheets 1.6mm thick. When i watch the z axis its complete stable. I turn on the spindle motor and the problem starts. I took the cover off the controller. There are 3 boards in it. The stepper driver / parallel port interface board, power supply board and variable speed spindle drive board. Should I try removing the variable speed board and put it inits own enclosure with its own power supply to limit interference?

Any ideas?

[awerby]

It sounds like RF interference. Is the spindle's power cable shielded? There should be a braided metal shield over the whole thing, attached to metal at the spindle end (but not at the VFD end). If it's not there, try installing one and seeing if the problem goes away.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[BrendonV]

Tried running a shielded power cable and attached the grounding to the spindle. No luck there. Any other ideas?

[daniellyall]

check all connections and make Sure there is not a loop in the earth, connected only at one end. one way to test for Rf interference is to put a TV that is tuned to a station beside the machine. so turn TV on then turn machine on if you lose picture you have Rf problems