Print Quality - Z wobble

#1

Hello all!

So I’ve been using my Peopoly Moai for about a year and a half now and other than some little issues with adhesion during my first month or so (which this forum helped me fix THAT DAY, so thank you for that!), I’ve had no issues whatsoever. I’ve had my Moai on a break for a little while, doing upgrades here and there, but not really doing many prints (Just didn’t have a need for it at the time). Now I’m ramping back up and getting some prints done and I’m running into a quality problem. Now I know just from looking at the print that it’s hardware related, and more-so looks to be z-axis related. I’ve got a couple photos here that show the issue. My setup is pretty straightforward:
-Moai 130
-Peopoly Heater
-Advanced FEP Acrylic/Tank
-Advanced Build Plate
-Custom 24V distribution terminal for main board power, heater, and side-mounted thermometer w/ built-in thermostatically monitored relay (power from 24V 10A PSU).

These prints were done using B9 for support generation and Cura for slicing, however I do use Asura as well.

First picture is overall prints. Outer prints had the same support configuration, inner had additional supports going up the key shaft added later:

For the remainder of the photos, I’ve marked out the issue in black.
Second is of print done at 100 micron layers. Spacing between markers is 4mm:

Third is of print done at 50 micron layers. Spacing is clocked at about 2mm:

Fourth/Final picture is of print done at 25 micron layers. Spacing is about 1mm:

All this points to something on the z-axis, but I can’t tell if it’s wobble or perhaps a backlash issue with the z-axis mount on the build plate arm. Since the issue follows layer height, that points more towards a backlash issue, in which case I would need a new threaded piece for my build plate arm.

What are your thoughts though? If you need any additional information, I’ll be more than happy to share. I’m teetering on the edge of getting the new heavy duty z-axis, replacing the current axis, and/or looking into the tripod assembly I’ve seen floating around. Any input is appreciated, especially from the @Peopoly team!

Thanks in advance all, it’s much appreciated!

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#2

Those lines will disappear if you turn your heater off during print - just use it to warm up the resin before start and then try a print with it off.

Here is a picture of my model with heater on:

And same model /gcode with heater off:

The lines are most likely due to too rapid heat changes. I’m installing a new heating system with PID controller…

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#3

These stripes come from the heater (temperature fluctuations). This can be seen by the fact that the distances between the waves become smaller, the longer the laser has to do on one level (waves = heating cycles).

More info: “PeoPoly heater problem, analysis and solution”

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#4

Well I’ll be… Went ahead and turned off the heater and that took care of it. I was honestly convinced it was z-axis issues but I ran a print overnight after only heating the build volume up and the lines went away. Thanks for the help!

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