Skipped layers

[printbus]

Moisture in the filament leads to steam bubbles that pop from the nozzle, often resulting in small bumps or zits in the print.

Re-reading the thread, I don't follow the height error you describe in post 1. The gcode snippet starts at a height of 3.65mm. A z-hop up of 0.75mm for moving to the next layer gets you to 4.40mm. The move to the starting location for the new printing layer includes moving Z back to 3.75mm, which would be the original 3.65mm height + 0.75mm z-hop hop - 0.75mm z-hop down + 0.1mm for the new layer height. How is 3.75mm the incorrect z-height for the new layer?

A new thought - PLA can tend to curl up at corners and edges - especially if the temp is a bit high or you're over-extruding. At your through-holes, perhaps this leaves a slight ridge that catches the nozzle on subsequent passes. This catching could cause a mechanical twitch throughout your x-carriage and extruder that leaves the nozzle a bit out of place until additional movement lets things settle back into place. Your 0.1mm layer height would be more susceptible to this than say a layer height of 0.2mm. Adding an effective print cooling scheme is very helpful in improving PLA print quality, and might be part of the solution you are looking for.

[Reaping miner]

Moisture in the filament leads to steam bubbles that pop from the nozzle, often resulting in small bumps or zits in the print.

Re-reading the thread, I don't follow the height error you describe in post 1. The gcode snippet starts at a height of 3.65mm. A z-hop up of 0.75mm for moving to the next layer gets you to 4.40mm. The move to the starting location for the new printing layer includes moving Z back to 3.75mm, which would be the original 3.65mm height + 0.75mm z-hop hop - 0.75mm z-hop down + 0.1mm for the new layer height. How is 3.75mm the incorrect z-height for the new layer?

A new thought - PLA can tend to curl up at corners and edges - especially if the temp is a bit high or you're over-extruding. At your through-holes, perhaps this leaves a slight ridge that catches the nozzle on subsequent passes. This catching could cause a mechanical twitch throughout your x-carriage and extruder that leaves the nozzle a bit out of place until additional movement lets things settle back into place. Your 0.1mm layer height would be more susceptible to this than say a layer height of 0.2mm. Adding an effective print cooling scheme is very helpful in improving PLA print quality, and might be part of the solution you are looking for.

That is the reason i am not doubting my slicer program. The G-code looks correct, but the nozzle seems to be physically higher than it should be. Later i looked at position of the Z-axis couplers to more easily see if the Z-height physically does change like it is supposed to, it looks like it does. (1/2 of 1/4th turn is 1/8th turn translates to a Z difference of 0.1 mm which is correct.).

I actually was printing the extruder body to be able to add upgrades (read: layer cooling fan.).

So i bought new calipers today (Digital, 0.01mm). My old calipers seem to be a piece of junk.... The diameter of the PLA (BQ, pure white) and ABS (FFFworld ABS++ black) are very similar. The measurements of both rolls were:
1.76mm on average over the roll, with mostly 1.75 plusminus 0.01 mm in 9/10 measurements, one outlying measurement at 1.8mm.

Surprisingly though, i did get overextrusion symptoms. I am going to check the Z stepper voltage first.

Update:
Upped from 2.2A to 2.5A, still "skipping layer".

Update 2:
Switched to 0.4mm nozzle, same settings: issue persists but seems to be dampened or masked a whole lot better. At least this is more useable to print parts for things such as cooling solutions.

Update 3:
Switched to 0,2mm layer height, same settings: seems a little better than update 2. Infill seems to have improved a lot.