Solid infill of overhang is bumpi
Hi all,
I am pretty new in the field of printing and running into some strange printing results.
Currently I am trying to print an overhang which is fine. But if the printer starts to print the solid infill of the overhang the infill is getting bumpi.
The nozzle is scratching then over this bumps on the next layer. If I ignore the issue the print will finish up and it looks fine but in the meantime it sounds horrible. 😀
I have tested with and without IS and reduced the printing speed for overhangs but without some improvments.
Any idea how to solf this issue? Can also share the stl or PrusaSlicer project. 🙂
RE: Solid infill of overhang is bumpi
For testing PLA Prusa Galaxy Black was used with the default settings.
Overhangs do sometimes warp upwards and this reduces the area for filament to occupy, as you observed they usually complete OK.
You might try switching to cubic infill which may improve dimensional stability but there is not much space in this print for the effect to operate.
Cheerio,
RE: Solid infill of overhang is bumpi
That's not the best solution to use cubic. This happens because Prusa Slicer fails to adjust the internal solid infill on an internal overhang. The software isn't able to detect the internal overhang in this case and prints solid internal infill with the normal speed which is too high, causing the lines to curl up or even break leading to holes. The workaround would be to slow down the internal solid infill speed down to 50 mm/s or so. However this isn't a good solution because if the model has lots of internal solid infill then the print time will be too long. Another workaround is to use denser infill, but it's also not ideal bc wasted materials. The best solution would be for Prusa team to implement a feature to detect internal overhang/bridges when printing the internal solid infill, and adjust the speed the same way for external bridge/overhangs. I understand this isn't as easy to do bc detecting internal overhang can only be done after slicing the model. But I think it's doable, just need to analyze each internal solid infill line in the g-code after slicing, and see if there's not much under that line. If not then it's an overhang/bridging internal solid infill line and needs to be slowed down.
Overhangs do sometimes warp upwards and this reduces the area for filament to occupy, as you observed they usually complete OK.
You might try switching to cubic infill which may improve dimensional stability but there is not much space in this print for the effect to operate.
Cheerio,