Distance between nozzle and heatbed after leveling

netzmark

Maybe 80gsm is 0.7. But today JGaurora gives calibration plastic sheet which is exactly 0.1mm.

If you look over DaHai youtube leveling manual, he is using 0.2mm metal feeler for bed corners and later the same 0.2 for mesh calibration. So if we'd have the bed perfectly flat where mesh offset is 0 in every points (let's imagine that theoretical situation) then printing is at 0.1 (if first layer 0.1) but bed is -0.2 - so we have distance 0.3mm! It prints in air.

I have followed his manual. Plus my table glass bed centre is 0.2mm under the corners, it means -0.4 if used 0.2mm feeler for corners!!! The mesh is definitely showing -0.2 in centre and is enabled. But I get any adhesion only if do babystepping -0.2 or add G29 S4 permanent offset -0.2. It means if I set distance ~0.1mm.

I'm not sure if my mesh leveling works at all... Tomorrow will do false mesh +2 in centre to see if it is applied at all.

netzmark

Note the friction is only in case of shity JGaurora bed (rails). What in case when the prinetr has really hard frame, bed? The calibration method still remains the same but no friction.

Prokktor

It seems I too had the nearly exact same problem.
I fixed it  with:
G29 S4 Z-0.275
M500

This moves your Z axis down 0.275mm permanently and is part of Mesh Leveling, which may need activation in your start  GCODE after G28 insert M420 S1

cybercow

I have / had the exact same problem, just unexpectedly the printer started to print the first layer "in thin air", occasionally few tracks would stick, but then everything else was sticking to the nozzle, not bed. The leveling was perfect! ... but when started to print the nozzle was too distant from the bed! I measured it with fitting multiple normal copy papers in between during the print. I did a normal 5 point bed level like 1000 times, mesh bed level another 1000 times, i tried every combination and trick i did read on the net about this thing!... different print speeds, layer thickness, line widths etc. ... updated the firmware, restored the firmware to factory, then gone back to custom, same thing was happening over and over again, then tried to print in different corners of the bed, and in center, nothing just nothing helped ... it was like 2 - 3 weeks of desperation ... then i did one last trick and - it worked ... read somewhere that hair spray can do. Finally i did the 1001th bed level procedure and sprayed the surface, the first layer started to print without any error. The thing i discovered is; the mechanics and build material of the bed in this printer is really poor, not only the bed can bend with temperature, but also the holding screws and springs are real crap, they have play, and suddenly the bed can easily change its height without notice, sink or go higher, even just few moments after level procedure, which is catastrophic for starting the print. The bed surface material doesn't help either, nothing seems to stick well, cleaning with isopropyl seems to help a bit, but you must just clean it every time. I don't know why but the problem seems to be fixed at the moment with using hair spray and over-lower the nozzle a bit?, will see how it goes in the future.