second layer gone  

Re: second layer gone

What is the layer height you are printing? Material? Print temperature?

Observation is you are printing too fast for the material. Or your nozzle is partially plugged - have you done a cold pull to clear the nozzle?

Re: second layer gone

Thanks for answer.
I am printing at 0.2mm layers. 0.4 nozzle. Using already proven Prusament PLA Vanilla White. In general I am sticking to known and proven configuration to limit possible factors.
I had similar ideas as you so I did a cold pull and have changed nozzle for brand new one. Did not help.
I was wondering what is changing between first and second layer. After playing with print settings I have narrowed problem to printing speed. If I slow down to 50 mm/s it works but prints look under extruded.
I will keep checking and testing different setups.

Re: second layer gone

Reslice and disable the print fan for all layers. Or try printing and be there when the printer finishes layer 1 and immediately reduce the print fan speed to 0.

Re: second layer gone

Disabling fan for all layers was one of the first tests I have done and it changed nothing.
In the meanwhile today I have checked Bondtech. I have tighten screw in that one on E motor and greased the other Bondtech with the spring. I have noticed that it was not rotating freely.
It helped a little. Next layers started showing up. Plenty of holes inside but visible.
Then I have made extrusion multiplier calibration https://help.prusa3d.com/article/d9j1xdg7vj-extrusion-multiplier-calibration and received Extrusion multiplier 1.125. With this setting first layer is visibly better. Top layer has less holes in it but still has some errors.
Right now I am printing it with Extrusion multiplier 1.125 and speed limited to 100 mm/s. Top layer looks ok but still not perfect.
So I thing this problem has something to do with extruder. It is generally underextruding compared to its normal work and the problem gest worse with higher speeds.

Re: second layer gone

Have you checked the Bondtech idler shaft for looseness? If the shaft isn't pressed in completely only one end is supported. This leads to extruder problems, and lots of clicking. This is a known issue and somewhere there's a video showing the steps to fix it.

Re: second layer gone

ok, after printing dozen of test cubes and same amount of different adjustments i finally have some results.
Thank you for your support 😀

I will share what I think have happened so it may help others.
1. Initial issue was blocked Bondtech idler that was not rotating at all. I have cleaned it and used some oil. It is rotating now easily however not spinning like it was new.
2. Since I was suspecting clogged extruder I have changed it to another one that required hire temps to print. That was the reason I had massive underextrusion at some point and still problems with higher speed print. Returning to original extruder helped. I will test propr temperature for new extruder some time later.
3. Anyway going back to old extruder improved situation but problem still persisted. Then I have found that I need to tighten idler spring screw way more than it was at the beginning. I suspect that it has something to do with Bondtech that is now rotating harder then at first.

So I am happy that I have solved that issue and learned what can influence my prints.

Re: second layer gone

You may want to inspect the needle bearings and shaft inside the Bondtech idler gear the plastic cage they run in can be damaged when run dry