Z stepper motor problem

Hi everybody,
I'm new here and wondered if anyone could help please. I bought a Chinese 6040 router about 6 weeks ago and everything was working fine. I have cut 4 or 5 jobs on it without a hitch. I'm running Mach3 from a windows 64bit computer fitted with a UC100 usb connection. Now for some reason the motor that controls the Z axis seems to have a mind of it's own. If I press the down key on my keyboard it will start to move down, but is very noisy. If I press the down key again it moves up. press the up key and it still moves down, press the up key again and it move up. I have no control over which way it's going. To check things I disconnected the Z cable on the back of the controller and connected the Y cable into the Z socket. The Y direction moves up and down the table from the Z socket as it should with no problems and does as it should. I have checked the sockets on the cable and all looks to be soldered well. Could it be the motor that's the fault. I have tried contacting the supplier and all I get is OUT OF THE OFFICE AT THE MOMENT. I did make a small video of the problem if someone would look at it for me to see if they have any idea of the problem. I'm new to all this, but trying to pick it up as fast as I can. Am I allowed to put a link to the video here? I don't want to do something wrong on my first post. I would be very greatful for any advice. Terry.

Hi Terry, This sounds exactly the same as the problem I had. Mine turned out to be a broken cable in the Z. It was making contact every now and then. Have you test driven the Z axis from another socket ?

These problems can be a bugger to find. My Z axis had a preponderance to go downwards and the job it happened first on was ruined and the cutter went on to gouge the bed afore I could get to the 'Oh Shite' button.

In the end I made a join with a connector that was fixed to the Z axis so there was no movement of the wires coming out of the stepper. My 3D printer has gone through 2 stepper cables on the only axis where the cable moves significantly. The breaks were internal in the wires and first time difficult to find. Second time I just replaced the cable at the first sign of failure.

Best of luck with your fault finding.

Cheers,

Rob

Hi Rob,
Thank you so much for your reply, I will try to get time to have a play around with it again this afternoon. I did swap the Y to the Z socket on the controller and all was good, so I know it’s not the controller. I will let you know how I get on mate. Them Chinese are s**t’s lol. They kept saying they couldn’t understand my email’s, so I made a video, uploaded it to YouTube for them. They then said they couldn’t open the video. Yesterday I lost my rag with them a bit and said give me an £80.00 refund and I’ll fix it myself. They understood that lol. Got an £80.00 refund this morning lol. Wish I’d said £100.00 now. Anyway mate, I will let you know how thing go. Thanks again, Terry.

Hi Rob,
I have pinned it down to the cable. Tried the motor on the y cable, and working fine. Have you any idea wherte's the best place to get the 4 core cable and can you get them made to order. I would like screened cable if possible. I might even change all three if I can.
Thanks, Terry.

I doubt if you can get pre-wired cables, there are too many options of connectors, wire size and length. You need to get flexible cable (perhaps someone will supply the type - I think it is CY) anyway CPC sell it by the metre, just get one hefty enough to take your stepper current. They also have connectors.

Now's the time to sharpen up your soldering skills :peaceful:

Cheers,

Rob

Thanks Rob,
Very much appreciated mate. I'll get the soldering iron out and knock the dust off lol. Will let you know how I get on mate. Thanks again, Terry.

Hi Terry, I've got Igus cables and cable chains and never had any issue. If I remember correctly my stepper cables are CF10.07.04 but I chose this model because I have very small bend radius chain.

Hi Paulus,
Thank you for the info. I will have a look. To be honest I have no idea. I think I will do all 3 cables while I'm at it. Thanks again mate. really appreciate it. Terry.

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Originally Posted by wrighty

Hi Paulus,
Thank you for the info. I will have a look. To be honest I have no idea. I think I will do all 3 cables while I'm at it. Thanks again mate. really appreciate it. Terry.

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As Rob has said I would suggest 4 core 0.75mm CY cable and connect the screen at the control box end to a star point (ie where all the ground points are connected)

Hi Clive, thank you. I'm going to try to get the cable today as I want to get the cnc back up and running. Thanks for your help and will let you know how I get on. I will have to have a look at how I'm going to ground the screen at the control box end. Thanks again, Terry.

Quote:

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Originally Posted by wrighty

Hi Clive, thank you. I'm going to try to get the cable today as I want to get the cnc back up and running. Thanks for your help and will let you know how I get on. I will have to have a look at how I'm going to ground the screen at the control box end. Thanks again, Terry.

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Strip back the sheaf and solder a wire to the screen about 150mm long folded back along the cable and heat shrink over it, then fix that wire to a common earth point.

Thanks Clive, That's made things easier now I know what to do. Great advice mate, Thank you. Terry.

Hi Guy's I just want to say thanks for your help. I'm all up and running again and all seems good at the moment. Fingers crossed lol. Thanks again guy's, really appreciate your help. Terry.

Quote:

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Originally Posted by wrighty

Hi Guy's I just want to say thanks for your help. I'm all up and running again and all seems good at the moment. Fingers crossed lol. Thanks again guy's, really appreciate your help. Terry.

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I take it you found the problem, It always helps others to divulge it.. Glad you got it working:cheerful:

No Mate, I just replaced the cable and it's working fine. I assume it was a break in the cable somewhere. The connectors both ends looked fine. Terry.