Z-axis losing steps

Spindle/VFD (Aftermarket)
1

I have the 1F Elite foreman with the PWNCNC ATC system.

I’m having a problem with lost z steps during long carves. After a 3 hour carve, when I move the z-axis to max height I get a hard limit z alarm.

I have spoken with 1F tech support and they made a couple of suggestions (the use of ferrites and check connections, moving the power cable from the drag chain ) which I have done. I still get the error.

I have an after market larger drag chain and I have removed the spindle power cables from the chain. They hang from the ceiling and away from the z motor.

Because the 1F tech support can’t resolve the issue they have played the “we don’t support spindles” card (which is false as I have a PDF document authored by 1F that states they FULLY SUPPORT PWNCNC spindles in 1F machines) and suggested I turn to the community.

I can’t be the only one who is having this lost z step issues.

Does anyone else have similar issues?

2

You did not say but do you also have the braking Z Stepper? I think that is important.
If you do then I would check you cable connections. One issue I had was a intermittent cable connection.
I took each cable connection and with a screw driver made sure each connection was good and tight. Did this right after I got my Elite foreman about 8 months ago and NO more issues, Working 100% for 8 months now. and I have been doing long 3hour+ carves. I have my spindle power cable in the stock drag chain and I do have ferrites on my spindle power cable.

When I say good and tight connection I mean I take the female side of the connection and make the hole a little smaller so the male side is good and tight going into the female side of the connector

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3

I do have the z braking stepper. I will check those connections again. Thanks!

4

PROBLEM SOLVED (I think)

The problem EMI is my cheap Amazon LED lights. I have 10 foot ceilings and 3 rows of 5 LED bars from Amazon. Shop is nice and bright.

I have tested the 1F twice with the lights off. Two different files, both past the 3 hour carve and no hard alarms. I’ve run both my CNCs at the same time with the lights off and no hard alarms. I’m convinced its those lights.

2 Likes
5

Phew! That would be incredibly hard for tech support to solve!

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6

I installed new led lights on the ceiling and ran a test for 4 1/2 hours. Z hard limit alarm. Damn!

I’ll test the same carve and timing again with the lights out. If I don’t get an alarm maybe I’ll
Just wear a headlamp in my shop :person_shrugging:t3:.

I wonder if fluorescent lights would create more or less emi??

Feeling defeated but will forge on.

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7

Hey Peter,

serious machines have cables that are shielded and the machine must be correctly grounded.

Shielded stepper cables:

To make your own cables, you can use shielded LAPP® or IGUS chainflex® cables. See Cable Connectors Used on the Onefinity (all machines).

Grounding the machine:

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8

It seems I’m still having issues. Installed different lights and I’m getting the z-alarm hard limit again.

Is there a chance that my z-motor with the internal brake could be causing problems?

Should I test with the z-motor that came with the 1F?

Thanks,
Peter

9

It sounds like its only the Z axis is affected, I would check the cable connections first.

Most likely this is not an EMI, and changing all the cables is first of all expensive and second takes a lot of time. In most cases this might not necessary if you do not use your CNC professionally.

The best way to find out if it is your light is to run the program multiple times, you do not need to cut anything, the spindle can be off, overnight with the lights once off and once on.

10

I’ve run the 3+ hour carve multiple times with and without the LED ceiling lights over the CNC machine.

100% of the time without the lights on I get no hard z limit alarms.

100% of the time with the lights on I get the hard z limit alarms.

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11

So, one thing to watch out for is the bright light coming down onto the homing sensors.
Try to cover the z homing sensor with some black tape.