Bubbles...

Can anyone explain how to solve this issue? I tried to increase the steps for the e-axis, de and increase Temperature, try some different retract settings, but the Problem still remains.

Use better quality filament.

What are your retraction settings? Geared, direct drive, or Bowen extruder set up? Your print also looks like you might be .01 or .02 over-extruding, judging by minor stringing and top surface quality.

Thanks for the reply. I'm using a kossel Mini Delta Printer with Bowden Setup. The retraction is 4.5mm with 60mm/s. I've measured the steps/ mm by 450 steps (if i extrude 10cm in repertier, i Can measure 10cm via caliper)

Think you are getting the blobs from retraction, but I am not experienced with Bowen set-ups. I get that on my geared extruder when retracting too much due to the print nozzle setting in one spot too long while retracting.

Also check temperature, experiment by adjusting your temp +/- 5 degrees at a time. Make sure your thermistor has moved, etc.. But yeah it very well could be retraction.

Hi everybody,

thanks for your input. Unfortunately I could not solve the problem. I started at Zero. I changed the Microstepping for the bowden extruder from 1/16 to 1/8 and measured the extracted amount of Filament. After 10 measures I stated the right step amount by 217. Then I changed the Microsteppings for the XY and Z axis to 1/32 Microsteps (from 1/16). I started with the 0.4mm thin wall to adjust the flow rate in kisslicer (1.73mm diameter from the filament and a flow of 0.89)

The thin wall measurement has shown the following results: 0.40, 0.40, 0.39 and 0.40. So nearly perfect.

Then I continued with a simple 15x15x15mm cube. Solid walls were 0.8 and 2 loops. The first layer sticks perfectly on blue tap and the results were far better than the old ones. But nut the cornes. As shown in the picture in every single corner you can see the bubbles (but a really nice surface on the walls). I tried to follow your advice and experimented with the retract amount and speed. I started with 1mm and 20mm/s and ended with 12mm and 60mm/s. But it had no result on the bubbles in the corners.

Purely coincidental I found out that when I decrease the amount of DELTA_SEGMENTS_PER_SECOND from 200 to 100, the bubbles in the corners disappeared, but are now ligthly shown on the surface. So the problem is not solved but shifted.

Any other Ideas?