0
$\begingroup$

I am printing on a Prusa i3 MK3 with white PETG and I face several issues when it comes to the extruder shaping the bridge and solid infill. For the record, the temperature is set at 230 °C for the first layer and at 240 °C for the others. The speed for the solid infill is at 80 mm/s. I print with an infill of 0 % and for reasons related to my work I don't want to change that and increase it. Is it a temperature issue? It's like the bridge infill doesn't stick to the perimeters.

After reading similar issues, I have increased the temperature to 250 °C and I still have the problem.

Photo of a 3D printed model on the build plate showing printing errors

$\endgroup$
6
  • $\begingroup$ What is the temperature of your heated bed? That together with the hotend temperature, print speed, first layer height and first layer width all affect the adhesion of the first layer. $\endgroup$
    – Hacky
    Sep 11, 2023 at 11:19
  • $\begingroup$ In hindsight, printing the first layer at that speed is not a good idea. Try to lower the first layer speed to something like 15mm/s $\endgroup$
    – Hacky
    Sep 11, 2023 at 11:20
  • $\begingroup$ @Hacky bed is at 85-90 degrees. But it's not a first layer issue because the first layer gets printed fine. It's just the fact that it builds the perimeters and when it's about to print the bridge infill it doesn't stick to the perimeters causing it to "collapse". I used the same formula (mostly talking about the 0% infill) w PLA and didn't have that issue (i'm aware they're different of course) $\endgroup$
    – yv3s
    Sep 11, 2023 at 11:33
  • $\begingroup$ your picture looks like the first layer, but I can be wrong. A first layer though, can't have a bridge infill as a bridge is something that spans over a gap. Coming back to the issue: try printing that layer a lot slower. PETG is not as "runny" as PLA in my experience and it likes to move with my nozzle. $\endgroup$
    – Hacky
    Sep 12, 2023 at 7:46
  • $\begingroup$ @Hacky Maybe it looks a bit tricky to the eye in the pictures. My apologies. But if you look at the gauge you can see the first layer underneath the problem (the detached bridge infill). The model is already 4mm thick in the picture so the perimeters are already done and it has started printing the bridge. $\endgroup$
    – yv3s
    Sep 13, 2023 at 11:04

2 Answers 2

1
$\begingroup$

Unfortunately I know of no setting like a "bridge infill - inner wall overlap" .

You can however break the top and bottom of the model up into 2 pieces. Use the "per model settings" to increase the thickness (number of walls) of the bottom part. That way the infill has some ledge to hold on to.

$\endgroup$
0
$\begingroup$

You could try reducing the number of perimeters from 2 to 1 only for the layer in which the bridge occurs. This leaves the second perimeter in the layer below as a bridge anchor, like shown in these two images: How to configure your slicer to properly support bridges. Or you could change the number of perimeters from 2 to 3-4 in the 3 layers below the bridge to achieve the same effect with less visible artifacts on the surface.

Other than that, you can try to reduce bridging speed and acceleration or switch to another slicer. I'm not sure if the Prusa Slicer derivatives like SuperSlicer or OrcaSlicer are better in this regard, but there's always Cura if you want to invest the effort to learn a new software.

There are quite a lot of issues with the bridging algorithms in recent Prusa Slicer versions. See the Github issue Add an option for setting bridge/perimeters overlap for a list of links.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .