Z Axis goes down when pressing up and goes down during home

[quest4life]

This happens to me week after week, for no reason that is conceivable randomly (other than occassion drilling straight into the dang table during a job I've got 50 times before without cause, warning or reason ...which is even more frustrating).



Finished a small cabinet door yesterday, today when I try and use the machine if I hit Up on z axis it goes down, if I hit all axis home it goes down (and will drive it's self into table until it dies trying if you let it), and nothing I do changes it. Power it, reboot it, unplug it, leave it sit, and so on ....and eventually 1, 2, 5 days from now when I turn it on it will work.



DOES ANYONE ELSE HAVE A SOLUTION. I Unplug controller, cables, power, hit emergency stop, reset, leave sit ... and NOTHING fixes it to date except a random amount of time off (sometimes more than a week) before suddenly it works again.....although at some point during that week will take a job I run regulary and drive itself into the table as deep as it can go for no reason and certainly not because of the g-code.



Please help. It's bad enough I'm still stuck with a CNC with a "4th axis" coming out soon ....that came out but "has no upgrade path for older systems ..." it's worse when I can cut a basic damn rectangular cabinet door for weeks at a time with customers screaming at me.



I've recommend this system time and time again as the right choice to strangers, but this is killing me.....



Please help.

[stevem]

Have you tried calling Chad at Axiom?
I wish I could help, but I have no idea on why that would happen.

[johnb]

While waiting on a response from someone who can actually help with your issue you might consider doing the following:
Tell us which machine you have (and how old it is).
Tell us which pendant controller you are using and how long it has been since you did any kind of firmware update to your controller.
Check your limit switches to see if one has moved (or fallen off) (unlikely, since this would likely not result in a "self-correcting" error of this magnitude).
Trace your electrical system all the way from each motor (starting with the X-Axis) and going through the controller box. (Might as well check all the way back to the main panel while you're at it). Make sure all the internal wires in your controller are seated properly. You may have some kind of power or neutral fault that's intermittent due to humidity, vibration, temperature, or phase of the moon.
Is your dust collection system grounded properly? Do you have a bare copper ground wire running inside any flex hoses? Static can introduce all kinds of gremlins.

On the board for a "competing product", I've seen numerous warnings that say that the dust collection hose should be electrically isolated from any part of the machine frame/base, so that internal ground wire should not be attached to the machine itself, or in contact with the overhead dust collector arm if you have one, since this arm is bolted to the machine bed. In order to accomplish that, the bare wire would need to be "not bare" as it passes through the metal tubing of the overhead arm, and would simply terminate by "hanging free" above the connection to the dust shoe at the spindle. Word has it that a static spark (from metal to metal) can "leap" over 1/2" in a dust collection system, so bear that in mind in your insulation/separation scheme.

[Axiom Tool Group]

We run across communication issues like this for a couple reasons.

Essentially the stepper motors get voltage signals that tell them to move in either the + or - directions.

If the cable that fits between the handheld and the white control box is either loose at one end....or backwards as some of these cables are molded to fit a specific way....then you can easily get cross talk between the pins which will result in missed directional communication.


The other possibility has to do with wiring either in the control box and at the stepper motor.

Generally, the best place to look is the DSP control board....which is the black control board that the handheld plugs directly into. On this board, each axis has its own terminal...which is nothing more than a green block that can be wiggled and pulley's free from the board.

The wires that are clamped to this terminal transfer the signals from the controller to the stepper controls and ultimately the stepper motors.


Over the years we have occasionally found that one of these wires will be poorly clamped and not getting a good signal...or clamped on the wire insulation so that at some points its making contact within the terminal block and others not so much.


If its not cable related, then this would be the next best place to look.