New to 3D printing - Error I cant identify

[Hamdotca]

Hi all,

 

I'm pretty new to 3D printing and am experiencing an error and cant seem to find anything that looks similar online.

 

For Context the print used a honeycomb infill pattern Bambu's Basic Black PLA, and printed on a ~15 degree incline. I'm more confused then anything, plus this is the largest print I have done yet so its making me wary of doing more

It looks to me like the weird print quality is only between the actual solid portions of the infill, making me think this is some over-hang error? But then it stops slightly further up the print?

The filament I used has been open and on my printer for about a month or so, so maybe humidity is also a factor? Ambient temps have been pretty consistent sitting around 19-20 degrees Celsius.

 

 

Thanks for help in Advance!!

[DoctorNick]

Looks like lack of cooling. Think of the orientation of the part to the fans. @Hamdotca

[Potatoes2241]

Can you link a few screenshots from the slicer, specifically showing the cross-section of the problematic region? I am having trouble orienting and estimating the size of the thing based on photos alone.

 

The defect like that can be caused by too much speed / not enough cooling, like @DoctorNick mentioned, but it may also depend on the "wall printing order", actually. I had defects like this happen when the inner wall was printed before the outer wall, so you can experiment with changing this option in your slicer. But this depends on the geometry of the model so it's a stretch, it may not apply to your case. Also, playing with the number of walls may affect this part and reduce the potential sinking in the infill pattern voids. And obviously play around with infill patterns, gyroid should be perfect.

 

So, slice the part again and check the following:
- The fan speed on the affected regions - if it looks too low play around with "cooling overhang threshold" and "slow printing down for better cooling";

- The infill pattern and walls - if the defects happen specifically where the infill produces an empty space, either increase the density of infill or change the pattern;

- Check the speed on these regions and, if necessary, reduce it using the height range modifier;

- As the last option try changing the wall printing order and/or the number of walls;

 

6 hours ago, Hamdotca said:

The filament I used has been open and on my printer for about a month or so, so maybe humidity is also a factor? Ambient temps have been pretty consistent sitting around 19-20 degrees Celsius.

PLA in general is not prone to getting moist unless you print in amazonian forests, so safe to assume this is not the humidity problem. Be careful with PETG tho.

[Thaldor]

You can clearly see the honeycomb infill coming through, the infill is too sparse and the actual layers need to span too great distance causing the them to droop. Either add more infill or add cooling and slow down print speed.

 

You can add modifier to that area (depending on your slicer right click the model -> Add Modifier -> shape you want, I recommend box for this), scale and move the shape to the affected area and when you right click the modifier box you either have directly under there "Infill" or something like "Add Setting -> Infill" and then put there like 15% or something 10-20% more than your general infill.

This will make the slicer calculate denser infill into the area of that modifier shape.

 

But taking a better look at your model, you have top layer drooping in the lower area too so, maybe change the infill type to something more supporting or just increase the amount of infill. In most slicers you can preview the print and move up and down layers so use that and check you don't have massive voids in your print. At least Prusa and Cura slicers are so stupid they don't consider infill voids as bridging and don't warn you about the massive voids in your infill that will cause top layer to droop into them.

[Hamdotca]

2 hours ago, Thaldor said:

You can clearly see the honeycomb infill coming through, the infill is too sparse and the actual layers need to span too great distance causing the them to droop. Either add more infill or add cooling and slow down print speed.

 

You can add modifier to that area (depending on your slicer right click the model -> Add Modifier -> shape you want, I recommend box for this), scale and move the shape to the affected area and when you right click the modifier box you either have directly under there "Infill" or something like "Add Setting -> Infill" and then put there like 15% or something 10-20% more than your general infill.

This will make the slicer calculate denser infill into the area of that modifier shape.

 

But taking a better look at your model, you have top layer drooping in the lower area too so, maybe change the infill type to something more supporting or just increase the amount of infill. In most slicers you can preview the print and move up and down layers so use that and check you don't have massive voids in your print. At least Prusa and Cura slicers are so stupid they don't consider infill voids as bridging and don't warn you about the massive voids in your infill that will cause top layer to droop into them.

Ohhh, I didn't even consider lack of infill being a problem, I think I printed this with like 5% infill so that makes a lot of sense, but why would on the front face did it only happen in the lower section? seems like if this was the problem it would have happened everywhere? or did I just get lucky?

[Hamdotca]

3 hours ago, Potatoes2241 said:

PLA in general is not prone to getting moist unless you print in amazonian forests, so safe to assume this is not the humidity problem. Be careful with PETG tho.

Thanks for this, I've been worried about it ever since I opened the spool!! Also thank you for the Fan speed tips, ill take a look into that too! 

[Thaldor]

2 hours ago, Hamdotca said:

Ohhh, I didn't even consider lack of infill being a problem, I think I printed this with like 5% infill so that makes a lot of sense, but why would on the front face did it only happen in the lower section? seems like if this was the problem it would have happened everywhere? or did I just get lucky?

It's one of those problems that generally isn't a big deal until something pushes it to be a problem, like too high temperature for the filament, not enough cooling, the shape is problematic (usually convex surfaces with too few perimeters) and just the normal stars being misaligned. Like it's not a problem elsewhere on your model (just the inclined surface and the lower section) so the cause is something quite small, could be just that the stuff on the left of the model (on the last picture) gets printed first and that blocks some draft from auxiliary fan or just the natural draft of your workspace. You didn't mention your printer but it's probably a Bambu so it can be something like using the P1S closed (PLA really doesn't like enclosed printers, even if you have the chamber heating off the printing itself can heat the chamber enough to affect the PLA print quality. Also at some point Bambu Lab didn't have active cooling of the chamber at all, so anyone who printed PLA kept the door open because otherwise the chamber heats up and print fucks up).

 

It's also a problem on infills that don't get that much use (at least what I have seen). Personally I default on support cubic 15% (15% is the average infill amount with support cubic, which is adaptive infill; it starts spare but gets denser closer to the top layers) and change it only if I use something like natural PETG or transparent TPUs where the supports are visible or there just is a reason to think more about the infill (model shape, strength...). Just watch this to get some hold of infills (it doesn't have support cubic or adaptive cubic (spares in the center and gets denser towards all sides) for reasons): 

 

[Hamdotca]

21 hours ago, Thaldor said:

21 hours ago, Thaldor said:

You didn't mention your printer but it's probably a Bambu so it can be something like using the P1S closed

I didn't even realize that I didn't mention lol, but I'm using a Bambu A1, so no enclosure, my based on your and others responses I'm guessing its the lack of infill