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The cube is a 2 cm x 2 cm with infill at 30 % and layer height 0.2 mm, more details can be seen below.

I'm printing with PETG using an Ender 3 printer.

There seems to be a gap between the perimeter walls, I have already referred to other forums and specifically: " How to fix wall separation in 3D prints (gaps in between wall perimeters)? ", but I still can't find a solution for it.

Most would suggest to tighten up the pulleys, I've tried that, but that didn't work. Others also suggested tweaking to a higher temperature, again I've tried from a range of 230-250 °C, but this also failed.

Infill and initial/top layers seems to be strong and all lines are bonded except for the perimeter walls.

More details regarding the problem:

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Here are my print settings:

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Dr. Mantis Tobbogan
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Brilliant Purnawan
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2 Answers2

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PETG filament is not entirely rigid and compresses slightly in the Ender 3's extruder gear and Bowden extruder setup. Tightening it will only make this effect greater. Being compressed at the point where mm of extruder advance is applied means less than the desired advance of at-nominal-diameter filament will take place. I find I need a flow of 104% to compensate for this.

When adjusting flow in Cura, make sure you get the main flow setting not the first-layer one (which is an additional factor on top of the main one and can be left at 100%), and that all the derived flow settings for each type of extrustion (walls, top/bottom, infill, etc.) all come out matching the value you set. When I first tried fixing this with flow, they didn't propagate right and I ended up testing changes that weren't actually doing anything.

With that said, you may have something else going on too. The underextrusion looks pretty severe, including in the top layers which you said looked okay. You should not see deep grooves between the lines like that. I suspect they're only bonded to the layer below, not to their neighbors. This could be a result of tightening the extruder pulley, or some other problem.

Trish
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R.. GitHub STOP HELPING ICE
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I agree with @R.. GitHub STOP HELPING ICE, looks like under extrusion you could try a flow rate test print like this link to try and dial in the value.

But probably worth just trying a flow of 105% and see if it solves the problem. Another thing worth verifying is that your printer is feeding accurately. You can mark out 100mm from the feed hole, then manually command the printer to extrude 100mm, then measure the distance from the 100mm mark. This will tell you if you have a feed problem.

Sneaky Puffin
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