just want to share with you my way of finding the right correction value for the life Z adjustment.
just in case that somebody still tries to get it right with the v2 calibration gcode that came with the kit, which i think is only of limited usability.
find attached a little gcode that should print a 75x75mm surface with 0.2mm height (PLA settings).
i simply print this file in a bright color (takes about 12 minutes) and change the life Z adjustment level in the middle of the print, when the diagonal of the square is reached.
so a little film is printed. a good idea is to write the settings with an edding at the sheet
i repeat the procedure until i get a completely smooth and homogenous surface.
in addition it's a good idea to measure the thickness of the film with a micrometer gauge or a digital vernier calliper
when you look at the attached picture, you can see at first sight, that the right foil (with the -365um and -400um) shows some small gaps, which indicates that you need to squish down the nozzle a little bit more.
furthermore you can see that the -500um setting delivered the best result, and as you can guess: it's thickness was exactly 0.20mm.
anything more to explain ?
just forget to tell you how you can get the film off from the heatbed without damaging it:
just use coolant spray at one edge. the sheet will immediately curl up and you can get it off easy as pie from the printing surface with your spatula.
edit 17th january: just replaced the attached gcode file with one where i added a "G1 Z=10.000 F1800" at the end, just to make sure that the nozzle moves up a little bit more (would remain at 0.2mm after the print).
edit 29th of august: removed the first test sheet (which has been downloaded more than 1000 times) and replaced it by the most recent one (v4).
update (14.01.2018): calibration surfaces for PLA, ABS & PETG
(generated with the latest S3D version, lin-advance, G87 and preheat procedure to avoid nozzle dripping (tnx 2 PJR)):
dem inscheniör is' nix zu schwör...