Sudden z height issues after dozens of absolutely perfect 1st layer prints
Hi there,
I am printing w/ a mk2, ABS (100/255), 0.25mm nozzle, 0.2mm first layer height on a 0.5mm glass sheet that I used to glue to the PEI sheet (clamping it down seems to always be in the way of the extruder head or frame). I now use a combination of glue stick on the outer edges and flash release tape. I found that sometimes I trap air under the glass sheet when only using the glue stick. I am using an enclosure, no fan. Running newest firmware.
I did some 30-40 successful prints with an absolutely insanely good looking first layer, absolutely glossy and perfectly level. I did remove and reapply the glass sheet several times (new sheet every time). However, recently there seems to be issues that render the prints useless.
The object is 6x8cm in xy-size, and in that relatively small space I now seem to have massive differences in z-height. To get it to stick to the glass, I do two skrits and a 5mm brim since live-z has to be adjusted every time ever so slightly. I used to have inconsistencies in the brim itself and raised my left print bed by 100 microns (L-100 in G80), lowered the right side of my print bed by R+100. That did help with my brim issues and the layer seems to be getting more consistent, although I still have some wave-issues on the right side of my brim as opposed to the left side which then looked perfect. It is sadly not possible to go above -+100 in G80. Anyway, when the printer goes on to do the 45°-passes for the first layer within the brim, the z-height seems to be off yet again as compared to the brim which looked good enough to do a good first layer (though not perfect).
How does the G80 compensation work anyway? I can't seem to notice the z-axis moving to account for that 2x 0.1mm difference, and there is no leveling-mechanism beneath the printer?
Interestingly, I have none of those first layer issues when printing without the glass sheet but solely on the PEI. This kind of made me suspect that the PINDA probe is heavily influenced by the glass sheet when doing the mesh bed leveling, but even cutting out small glass sheets of the size of the object and carefully not covering any of the 9 meh bed leveling points did not seem to resolve my issues.
I am absolutely flabbergasted as to whats causing this. What drives me nuts is that it worked perfectly at one point with zero issues, just wonderfully consistent. I changed absolutely nothing (granted, new versions, new STL, new Sheets applied, but the rest ist the same) that would reasonably casue something like this.
A lot of questions and a tough nut to crack. Hopefully someone can guide me in the right direction. Thanks!
Dominik