Going crazy with lost Z steps...

[Frunple]

Pulling my hair out over this one...

New machine, been working fine but I just tried a lithophane and there is a considerable amount of movement in the Z axis. Always moves in the + direction.
Rewired everything today, no change.
Checked the Z hardware and nothing is loose or binding.
Lowered the velocity and acceration, almost to a crawl, and it still loses steps.
Swapped cables, no change.
Did not swap motors but they are brand new (not that that matters much).
I'm thinking of trying a different computer but that's just grasping at straws I think.

Other than swapping motors, anyone have any other ideas to nail it down?

[ozymax]

Slipping drive coupling?
I had this issue a year or so back and found a very small crack in my drive coupling.

[Frunple]

Slipping drive coupling?
I had this issue a year or so back and found a very small crack in my drive coupling.

Nope, checked that too. I included it in the "z hardware" above but thanks for the idea anyway.
I also thought of electrical interference, doubted it since it's only one axis, but rewired it anyway will no luck.
If I get time today, I'm going to try a different computer.

[garylmast]

Some manufactures put too small of a stepper motor for the Z-Axis, especially if you have a larger spindle, and just can't hold the weight, causing the lost Z steps. On my present machine, not only did I change the stepper motor to a larger, two-phase, high torque, but I also added a 1" x 8" spring, I got from Home Depot, to help hold the weight. For a new machine I just bought and expect to get in a few weeks, I had them add not only the larger stepper motor, but some gas cylinders, that should stop this problem.

[ger21]

Disconnect the motors, and turn the leadscrew with your fingers, up and down, for the full lengths of travel. If it's tight anywhere, that's probably your problem.

[COWBOY1296]

The only time that it has happened to me is when the brushes in my router were worn out. Just a thought.

[garylmast]

Another problem maybe your bit does not reach the bottom, so your spindle bottoms out on the frame and you lose steps that way. Check to see if it reaches the spoilboard, if not, either lower the spindle down in it holder or adjust your bit down.

[Frunple]

I have the same size motor on all axes, so I doubt it is that.

As stated, no binding or any sign of anything loose in z axis. Checked with motor connected but not powered so no holding torque.

Had just cleaned out the router and brushes are more than fine.

Have more than enough z travel, 8" actually, and no where near the bottom.

Gonna swap motor with Y axis now. I can't think of anything else to try except another pc but I doubt it's that.
Then again, I doubt it's the motor also... gotta try though.

Driving me crazy...

[Frunple]

As expected, not the motor. But I think I found the culprit!
Turns out the fan I put on my G540 was no longer working. After trying a smaller lithophane as a test, I found the fan not working and touched the back of the 540, extremely hot!
Going to email Gecko now and see if that will cause lost steps but I think I already know the answer.
Anyone else know for sure, please chime in.

[zeeway]

In my early CNC efforts, I was going crazy over lost z steps. I had used shielded signal wire, so I was pretty sure that was not it. After ruling out all things mechanical, I decided my Gecko 540 was the culprit from overheating - put a fan on it...and the problem did not go away...but I still think it is important to keep the Gecko cool.

Finally, after many failed attempts found that my parallel port connection to my CNC was losing data. Changed to using SmoothStepper, and that finally was it. So while that solved 99% of the problem, I still had mystery stops in data trans - the final fix was to use a common ground wire between my control pc and the machine control.

Hope you track down your problem.

Angie

[garylmast]

I have the same size motor on all axes, so I doubt it is that.

All my stepper motors were the same also. I went through everything, including changing out the USB card, re-calibration, changed bearings, double springs to hold the spindle up, switched motors from Y to Z drive, replaced it with a new same size motor and even had the manufacture log on to my computer to see if they could figure it out. It was finally solved by putting the larger TWO-PHASE - HIGH TORQUE stepper motor on, plus adding one spring to help hold the spindle. Since the stepper motor was twice the physical size, I made new a mounting directly over the spindle screw and used a direct coupler. You might tell the manufacture of your problem and talk about a possible motor upgrade and see what they have to say. Hope you figure it out, because I went through a nightmare figuring mine out.

[Frunple]

Thanks but as I said, it's moving in the positive direction. So if I start at zero, I end at +.1.

[garylmast]

Never asked or was told what controller you're using. Calibrating your axis sounds like it may be needed. If it's Mach 3, it's under Settings.

[Frunple]

Not needed. Thanks.

[IslaWW]

Frunple...
I (we) may have been hung up on the lost steps verbiage. Can you confirm that no matter what you cannot get the machine to move negative?

If this is correct, then there may be no loss of steps, you may have a loose or broken wire on the Z axis direction pin. There could also be a bad chip on the direction circuit. This can easily be checked with an inexpensive multimeter. Disregard if only positive movement is the case.