Proud owner of a P1P here. Everything had been working flawlessly since I got the printer, until I went out of town for a week. For over 7 days, it sat doing nothing. Then, a day or 2 after returning, I tried to print a simple design, to find that there were these lines offset from the print that don’t appear in Bambu Studio’s “Preview” tab. (See attached images). They seem most common on the underside of a surface, on overhangs and such, but I don’t get the impression it’s a lack of support considering how fine other layers next to the issues are. These imperfections do not appear of top of the model; only on areas facing downwards. I’ve tried running the vibration compensation calibration, re-slicing the model and other models, and both updating and rolling back the firmware. Still not fixed.
Did you re-dry your filament yet? Moisture can easily become an issue, especially when sitting idle, and will show first on overhangs. If nothing else, it eliminates a likely root cause and facilitates further troubleshooting.
Can also be a thing of the extrusion temp being a bit too high.
If the filament is too soft it can stay soft for too long and the next layer creates a growing mess.
Perhaps, although I’ve always printed PLA at the same nozzle temperature (220 C) without issue. Although if moisture is the source of the problem I suppose having a high temperature would also be a factor. I’ll see what happens once the dryer is done.
Welcome to the community. I can confirm that it is not the model so it therefore must be your filament or less likely, your settings. If you’ve printed this before and did not change any settings, then the most logical issues as @EnoTheThracian states, is filament moisture.
If it’s not wet filament as others have suggested may I ask are you still using the sd card that came with the printer? When these go bad they can cause a lot of issues, maybe worth swapping it for a decent 32gb one.
Thanks everyone for their input. I did a test print after drying for 4 hours at 50C in my Sunlu dryer. The issues have not improved. I’ll let it dry some more, and I’ll also see if I have a new microSD lying around, as suggested by @oddsandsods .
If it still occurs after drying for 8h at 50-60°C, then we need to look at other causes.
Calibrating the filament after drying will probably be a good idea as well.
Due to the irregularity of defects, I doubt it is linked to the z-screws but it is always a good idea to run through the periodic maintenance recommendations at the latest when encountering issues. None of that may be related, but it eliminates possible root causes. Oh, and have a look at your nozzle at this stage. Even slightly bent nozzles are easy to spot and replace. They tend to cause the strangest errors. Bambu Lab P1 series printer Maintenance Recommendation | Bambu Lab Wiki
After that, it makes sense to dive into the settings. In addition to Nozzle temp, retract, cooling, speeds, layer height (try adaptive layer height for overhang issues. Worked wonders for me with PETG), can all be helpful information.
Forgot to add that you may want to weigh the spool before, halfway through and after drying. I do not do that myself, but I think I can predict @Olias next question on that topic
I dried for 8 hours at 55C, and the issues are still present. I didn’t let this one finish, but this image shows that there doesn’t seem to be any improvement. Checked the nozze- it does not appear to be bent or otherwise abnormal.
I’ll run through a filament calibration via OrcaSlicer, and if that doesn’t work I’ll mess with temperature and other settings suggested by @EnoTheThracian and report back.
Have you verified the fan speeds? It’s a long shot but it may be that this could because your not getting sufficient cooling. You’re going to run a temp tower in Orca’s calibration menu.
If you temp tower looks like the one on the left here, then you have a fan issue. I was having issues and could not figure out why. I hadn’t noticed that the part cooling fan connector had come somehow disconnected, likely because of vibration. I reseated the connector and reran the calibration(on the right)
Thanks for reporting back. Calibration is often important when rheology changing things occured. Like drying, a new spool or using a spool that has not been used in a while.
Typically, when needing to investigate settings, it does make sense to post screenshots of them. Material settings, Quality, Strength and, in this case, support settings may all become important. I can not be certain from the pictures, but maybe @Olias used a different overhang threshold angle for the support structure compared to the one you are using?
And to complement @Olias post just now, rarely (but somethimes), the object placement on the build plate can affect cooling performance. When my printer was still living outsides I did get issues in the rear and front left sides from drafts through the poop chute and the front left gap. But they always showed a clear defect origin direction which is not what I am seeing in your pics.
Here is the temperature tower. It is obviously not ideal. HOWEVER, I opened up the magnetic hot-end cover and found that my fan had somehow come unplugged. As in, the connector from the fan to the rest of the electronics had been disconnected somehow. I don’t know how or when this happened, but I am running another temp tower now that I’ve plugged it back in. I would not be surprised if that was my issue, but I’ll wait until its finished to be sure.
I had similar issues when I tried a new batch of PLA filament.
No matter what I tried, even otherwise unproblematic overhangs, especially rounded ones kept failing.
Bridging turned into a real nightmare as well.
As a last ditch attempt to rule our problems I did the entire filament calibration from scratch.
Not really expecting any changes as I used the same filament from the same supplier before and never had issues.
To my utter surprise the rolls needed a MUCH lower printing temp to at least work half decent.
I had to go down 185 to 190 degrees Celsius so the filament would come or firmer than warm honey…
Did not mean I could print it faster, it was just a ‘bad batch’.
I also noticed that some matte or otherwise modified filaments often misbehave where you don’t expect any problems.
Try the print again but place the model so you have the most problematic area to the front for easy observation.
Two things can cause this problem:
The filament curling up.
The outer wall loop not having enough bind with the rest of the model.
In the later case you can observe a string like effect - the filament comes out but not really stick well to the model.
Increasing, rounded overhangs can be a double pain.
Not only can the filament curl up, if it shrinks, even a little bit, the outer wall acts like a stretched rubber band.
It creates tension on the still softer parts of the model and this effect accumulates until the model solidifies enough to be stable.
A good way to compensate for this problem is to slice with a variable layer height.
Here the slicer will use thinner layers for the worst parts of the overhangs in order to increase the layer bond and overlap from one layer to the next.
Adding a wall loop or two can also make a ton of a difference.
Last but not least: Reducing the speed for overhangs will make it easier for the filament but needs a fine balance as layers getting to hot tend to curl up more when cooling down.
Well, I’ve solved it. Really I solved it yesterday, but wanted to do a few prints to be sure. I increased the nozzle temperature from 220 to 230, and now things print even better than when I first got the machine. Marking as solution. Thanks everyone for their input.
