Printer Model: Kobra Go
MCU / Printerboard: Trigorilla klippy.log
Describe your issue:
Hi all – I’m new to Klipper but been doing 3d printing and Octoprint for a while now. Slicers I’ve been using are PrusaSlicer, IdeaMaker and most of the time, Cura.
I switched my Kobra Go from Marlin to Klipper (Fluidd) and converted to a direct drive using the extruder motor that came with the printer and the hotend. I’m happy with my results so far with Pressure Advance configured until I switched to a high flow hotend (volcano). See attached picture.
After switching to volcano, I’m now seeing gaps at the topmost layer no matter how many times I tried changing PA starting from the uppermost best corner (using pressure advance tower) going down. No matter how I adjust, I end up with gaps in the corners.
I even switched filaments and thought that it could be due to the filament but same thing. I’ve used the same Cura parameters I used before switiching to high flow.
It’s not clear what you’re doing here. Are you printing these test cubes as tuning towers for PA? The log shows tuning tower running, and PA incrementing throughout the print. I would expect the upper most layers to have too high a PA value resulting in the gaps you’re seeing.
Hi jakep - The klippy.log I provided were generated AFTER the picture above was taken.
I thought of re-doing PID tuning and PA tuning in hopes to resolve it. After that, I printed a calibration cube and that’s when I took the klippy.log. I did cancel printing the square_tower.stl without finishing it a soon as I saw the corners are already showing underextrusion.
In spite of re-doing though, I still see that the top surface have gaps in the corner walls. If I lower down the height value in the PA calculation, I get over extrusion at the top and still have gaps in the corner walls. (see pics)
It’s weird though I’m printing at the same speed as the standard hot end (100mm/s) and I’m not having the gaps. Only when I switched to a high flow hot end is when I got the gaps. I didn’t change any parameters in the profile except the physical hot end.
Your pressure_advance = 0.06410375 is quite low, which is generally good. Some unsorted comments:
I recommend to rather go the lower end of PA when tuning instead of the upper end
I had a similar effect when I very sloppily mounted a hotend and it was far from parallel to the bed. Somehow this “dragged” the filament inwards leading to such gaps
Finally able to fix my issue. I was simply barking at the wrong PA tree.
For some reason, while my overall speed was set to 100mm/s, for some reason the inner wall speed was set to 137. Not sure how it happened and I’m certain I didn’t set it myself. Anyways, I have found a good value for my PA advance and also solved the issue with the gaps on corners.
