Thanks for commenting on my post.
Regarding the missing layer.
I first noticed this on a few single layers in the beginning of the print (This is shown in the picture in my first post)
It then becomes worse in prints after this with more layers and eventually all layers having insufficient filament.
Temperature is set to 210ºC and I don't use any adhesion no my plate when printing PLA. I do though clean the plate with a damp cloth before printing and before the bead heats up. This has worked great for me for many prints.
As I see it everything points towards wrong temperature despite having changed both sensor and heater haven't changed anything. Why is that my opinion:
1) When I feed "new" material the printer does not have any problem pulling the material to the print head and eventually filament comes out out the nozzle. However - the flow seems slower than usual.
2) Filament that's stuck to the nozzle - in the past it was easy for me to wipe if off with a piece of cloth - not anymore. The filament is more "sticky" than fluid.
3) If I pushe material directly to the print head ( by removing the Bowden tube from the print head and push material that way ) I can press material through the nozzle but even then I can't push it so the flow is "normal" meaning the filament flows slowly.
4) When I retract material during the change material procedure - that works Ok but it there is a long thin thread of filament at the end
5) In the beginning of the print when the nozzle extrude material - in the past the material flowed down to the bed and form a nice cylinder; now very little comes out and sometimes not enough material to even reach the bed before the print starts.
6) When I print the brim the nozzle pulls the material with it. If I pause the printer before the actual print starts and clean the brim from both the bed and the nozzle generally the first layer prints OK but I do print very slow (like 10 mm/s). Once the 2nd layer start, the speed goes up and the fan kicks in - my problem starts. Sure I could reduce my print speed in general and perhaps not use the fan - but there is a problem and I would like to solve it.
As for the assembly of my print head - I have attached one but I've taken this apart so many times that I'm fairly confident that it's assembled correctly.
I guess the only thing I haven't tried is an accurate measurement of the nozzle temperature (I don't know how to do this correctly and as in my original post - I did try with Weber thermometer) but given that sensor and heater is replaced the only thing left would be a "damaged" ADC on the controller board. Is that even plausible ?
Is it possible to use the temp sensor input on the controller board? Or does it use the same ADC ?
If all of the individual components are ruled out, perhaps it is the way it is assembled after one of your cleaning sessions? Could you share some pictures of how your print head / bowden tube and other crucial components are assembled?
Is the missing layer(s) always on the same height or does it vary?
Have you tried cleaning your threaded Z axis? Although it shouldn't cause underextrusion it can mess up a layer.
Did you ever clean your glass plate and do you use any adhesion?
What temperature are you printing with usually, 210ºC?
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