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Everywhere you can read how to try to "hide" the seam, but nowhere there is an attempt to eliminate this problem. And the proof that it is possible is the prepared G-code added to the Ender printer on the SD card. (the exact name of the file is 3-Cat.gcode)

This little figurine has no seam at all! The print is so perfect that I can't believe it.

The question is why slicers don't create such G-codes so that the seam is hidden inside the printed object, not on its wall.

I have printed this figurine six times already, in different colors and different brands of filament. All prints are perfect!

What do you think about it? Can this be done in a slicer? (I can add this file somewhere but I don't know where.)

Seam in diferent retraction distance (retract on layer change turned on): seam in diferent retraction distance

Rigid
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3 Answers3

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This answer adresses the seam in the cat model. While it appears that there is no seam printed in this model, it most certainly is printed, but it is cleverly hidden in a sharp corner for you not to see the seam. Furthermore, by clever use of printing the infill first and then the outer perimeter, it appears that there is no seam. There isn't a definite start and stop (no retraction from infill to outer perimeter) and continues inner perimeter printing after the outer perimeter.

You can load the model in an online G-code visualizer to see for yourself. The Creality Cat is a specific showcase to show it's capabilities, but cannot simply be applied to all geometries, a sphere is difficult to print perfectly.

0scar
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It's done by tweaking the retraction setting in your slicer.

In Cura the main setting affecting this is under 'Travel'.

In the 'Travel' settings is 'Enable retraction', and 'Retract at layer change'.

This will retract the filament and you won't get a seam.

Kilisi
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Getting a seam that's not ugly is a matter of having proper retraction and Z-travel settings that don't let the nozzle ooze when starting/stopping an extrusion. These differ for every printer, but the settings in the Creality-sliced file are 0.8 mm retraction length, and 40 mm/s retraction (and unretraction) speed. These are a very good baseline to start tuning from for a direct drive extruder. Otherwise I don't see anything remarkable about their slicing. You can open it up in a gcode analyzer like https://gcode.ws or https://gcodeanalyser.com to see where their seams are and check if anything else looks special to you.

Faster Z moves will also help and let you turn off "retract at layer change" if you like, which can help. They have not done this in their file; it's sliced with a painfully slow 5 mm/s Z travel speed. Cura doesn't let you access this directly but it reuses the Z-hop speed, even if Z-hop isn't enabled, as the Z travel speed for layer changes. Increasing it won't help much without also increasing the Z acceleration in the printer firmware, though, since the moves are so short they don't have significant time to accelerate. I use 80 mm/s with 750 mm/s² for Z on my Ender, but I'm not sure if that's achievable without TMC 2209s stepper drivers in Spreadcycle mode. In any case, you can get completely acceptable seams without fast Z travel as long as you have "retract at layer change" on.

R.. GitHub STOP HELPING ICE
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