Hi everyone, I’m trying to track down a very stubborn print quality issue on my Bambu Lab A1. I am getting a single, continuous vertical wavy/bulging line from the bottom to the top of my prints.
Printer & Slicer Setup:
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Printer: Bambu Lab A1
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Material: PETG (Dried, printing at 240°C)
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Slicer: Bambu Studio
The Symptoms & Crucial Clues:
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It is NOT the Outer Z-Seam. I set the seam to “Random,” the outer seam scattered correctly, but this specific vertical line remained in the exact same spot.
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It follows the model, not the bed coordinates. I moved the model 5cm away from the center and rotated it 45 degrees. The artifact rotated and moved with the model. (Ruling out X/Y linear rail notches).
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CRUCIAL CLUE: I printed a cylinder using Spiral Vase Mode, and the print came out 100% PERFECT and smooth. The vertical line completely disappeared!
What I have already tried:
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Disabled Timelapse completely.
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Formatted the MicroSD card.
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Checked Slicer Travel paths (no travel lines crossing that perimeter).
My Deduction so far: Since Vase Mode is perfect, the mechanics (Extruder gear, belts, rails) are fine. This seems to be a layer-change/retraction artifact specific to PETG, even when the outer seam is randomized.
Has anyone solved this? Could this be related to the Inner Wall Seam alignment, Flow Dynamics (Pressure Advance) calibration, or an Arc-fitting bug? Should I switch to OrcaSlicer for better Seam control?
Any advice is highly appreciated!
