Mach 3 DIY machine loosing steps

[wfws]

Hello!

My issue is my axis loses steps, mostly on the Z axis, but also sometimes on Y. The Z axis will lift to move to another position, and loose its position, so that next time it lowers into the material it is no longer at correct depth. Also, I notice that when I click reset on MACH 3,. my axis all lurch maybe half an inch away from soft limit settings, even after zeroing the machine coords.

I have had this problem intermittently for some time now, and have tried many things.
I have the controller box and computer on separate dedicated breakers.
I have all pieces grounded- computer, controller, table, gantry, and Z axis- to a common ground point.
I just replaced the Z axis with a new linear bearing/ball screw rated for 100lb vertical load.

My system uses Mach3, and individual Gecko drives controlled by a Dell PC with a parallel port that has no internet connection at all.

Right now, I can't rely on the machine to cut for 10 minutes without error.

I'm now considering these potential causes:
1) connections/cabling
2) heat in controller on Gecko drive modules
3) issues with parallel port

My questions- how do I troubleshoot this? What would you recommend as a next step.

Thank you!

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[awerby]

If it's not working for 10 minutes at a time, it's probably not a heat issue - that takes longer to build up. I take it that replacing the Z axis assembly didn't help with the issues in Z. Have you tried an "air" run, well above the table, with the spindle turned off? Sometimes errors can be traced to RFI from the spindle wires. Have you tried lowering the acceleration values (cutting them in half) for the axes that are faulting? Sometimes the motors loose steps because they're trying to accelerate too hard at the beginning of a move. Do you have current-limiting resistors in place that match the current of your motors? Have you stripped your control computer of extraneous software, like Windows Update, and internet stuff? Often a computer will abandon its job of spitting out pulses when summoned to update something, or to save power when it feels nobody's paying attention.

If you shared some more details about your machine - like the type of motors you're using, the power supply, some pictures of your wiring, the computer you're using, the type of spindle, and the mechanicals, it would be easier to figure out what might be happening.

[steve323]

We need a lot more information about your machine to debug a problem. All we know is that you have a Gecko controller, Mach3, and ball screw on the Z axis. All these are expected to operate quite well. What type of power supply do you have? If you have Gecko 540, then the optimum power supply should around 48V and enough current to meet the needs of the steppers.

Steve

[skrubol]

I agree with all of the suggestions above, but could you also explain the 'lurch' near the soft limits? That would seem to indicate a mechanical or configuration issue rather than an electrical one.