Under extrusion issues after support layer

[Clayton.Baxley]

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Having an issue with this part the layer after the support interface layer height. Under extrusion and layer adhesion failure. It is more pronounce with PETG-CF than PLA or PETG-HF. Does this with independent support height on or off and is consistently in the same spot no matter which director the part is rotated. It has to be printed on its side due to orientation of the layer to how the part is in use. Layer height is set to .16 on high quality settings. I have increased flow rate (1.02) and temp (260). Same issue at the same layer height if I use standard supports or use a support interface material. I turned off slow down for overhangs and it dramatically improved the problem, but now the print quality for the first couple layers after are suffering. Any ideas on how to fix this defect?

Update:

So I set the layer height to .20 after reading the PETG-CF prefers a taller layer height and was still having some issues. I also oriented the part with the 45 degree beveled edges facing the fan and it significantly helped with the quality of that edge. I had read about running the print on silent solving overhang issues while running PETG-CF so I gave it a try and the parts came out dang near perfect. Does anyone know exactly what settings I should change in the slicer to mimic silent mode? I read in one thread it cuts the acceleration speeds and layer speeds by 50%, but in another thread they said it was just the acceleration speeds that are cut by 50%. Can anyone confirm which is correct?

[eried]

thats a very difficult print

1. get support material for the interface, so the top gets a solid base, it will still be weak where the underextrusion is now

2. design the piece in a different way, i.e.: split in half and join later

[Clayton.Baxley]

I am using PLA as an interface material now. All the issues seem to have been resolved with some setting changes and running the printer on silent mode during the print. I would like to change the setting in the slicer to mimic silent mode if possible so I do not have to try and remember to do so next time I need to print a batch of these.

[eried]

nice, but any pressure will split that piece on that point. is it for something mechanical?

[Clayton.Baxley]

It’s is basically an overtravel stop in a rifle lower for the fire control group. I tried to tear one of them apart and it just folds at the joint until the leg breaks free, unlike the picture parts that snapped off at the layer line. I’m sure it could be stronger, but should be good enough at this point. Hopefully.

[NeverDie]

Most likely just setting the maximum volumetric flow rate in your filament settings to a much lower number will give you the equivalent of silent settings. It’s the master knob for turning down all speeds and accelerations by the right proportionate amount without having to tweak them all individually.