Help Diagnosing Problems

It has been a while since I have printed on my MP3DP Repeat. So I have turned it back on and tried printing a few Benchys. Not the best results.

Clearly there was an issue with the hull of the boat. I don’t know what the hell happened. But looking “top-down” on the part it appears to have printed fairly decent.

Can someone suggest what may be the issue with this print and what parameters I should play with. Of course, the idea of the Repeat is print pretty quickly so I’d like to keep my print speed pretty good while adjusting other parameters first.

Here’s the slicer settings for this print:
Hatchbox PLA
0.2 Layer Height
218C Nozzle Temp
63F Bed Temp
60 mm/s Print Speed

My first guess is the nozzle temp is too high. Or the past chilling fan is too low. When it finishes the “deck” of the boat, the layers get a lot smaller, and that’s where they get so squishy. My guess is that those layers aren’t cooling before the next layers come down.

But the cabin and chimney are looking ok. So maybe the slicer is slowing down on those cabin layers, and not on the hull layers?

Yeah im thinking nozzle temp as well. Let me try to print at 210C and report back.

This PLA recommends 210C-230C so this will be on the very low end.

What PIN on the SKR Pro should the part cooling fan be plugged into? I am trying to control that fan directly with M106 and M107 and the fan is not responding.

I also just tried turning the fans on using the LCD screen. There is an option for Fan 1 and Fan 3, I put them both at 100% and neither fan turned on. Seems abnormal.

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Fan 1 or fan 0 should be the part cooling fan.y first printer had an adjustable part cooling fan, and the extruder fan was on whenever the printer was. Things like case fans weren’t a thing, so that is the order I think they should be (part, extruder, extra like a case). But it probably depends on your marlin configuration.

Well now I can get it to turn the fan on. I can use M106 PC8, M106 PE5, M106 PE6. All three pins each turn on the same part cooling fan. Weird. But atleast I can turn it on manually now.

Well I fixed it. The PID tuning of the nozzle temp was indeed the fix here (ref MP3DP Repeat Nozzle Temp) and it made quite the difference.


Much better results! Still some more fine tuning needed, but this was the bulk of the issue.


Ah, good. You got those bumpers tidied up… Embarrassing to leave the dock with those still over the side.

Got the boat all cleaned up, bumpers pulled in, and ready to set sail in the trash can.