Live Z calibration nightmare.
Kit built MK3s+ and been printing with PLA for a month and only minor issue. Moving to PETG and have not had great success. So, this weekend, spent hours trying to get it working right. I am using a Satin sheet and did the Z level calibration before printing. Bottom of prints look like crap so started to check again and found that printing the cube with vase mode showed my extrusion was about 7% less than required. Today, I thought that changing the extrusion multiplier, would change the Z calibration so I decided to check it using the Calibration Strip for simple Live Z/First Layer calibration strip. I was expecting it to go very fast. Was I wrong.
After 6 runs, I thought I had it close and left the printer for about an hour. Came back and started to fine tune in the range from before the break. The first run was a disaster so I did two more runs of the exact same settings and in all cases the runs got better. See the attached photos. The first run is like a brush. Once I cut the edge off, the different runs just separate. The second run is much better where the centre adjustments are sticking together pretty well. The third run, most of the lower side is really well stuck together.
Settings were from -1.558 to -1.575 going from right to left in the photos.
Printer is in an enclosure. Temperature is about 30 degrees with the doors open and RH is about 20%. Same spool of Prusament PETG.
RE: Live Z calibration nightmare.
Second photo since I couldn't add it at the same time. This is a closeup of the test strips right hand side.
RE: Live Z calibration nightmare.
Okay, after checking for nozzle clogs and anything else I can check, I redid the tests. Almost an exact repeat of the images posted before. The third test is pretty nice in the centre but the first test looks like a brush.
I did all tests today with the doors open on the enclosure. Starting temps/RH for the three runs are 20.1° 28%, 23.1° 25%, and 24.0°/24%
Same Prusament PETG as the first runs. I will contact Prusa for this issue now since there have been no responses here.
RE: Live Z calibration nightmare.
After much frustration, I went to a different approach than looking at how the prints came out. I measured the Live Z calibration thickness and found that I was not close to the height I should have been. Oops. Both sides of the live Z look bad but the middle looked good. When I measured the thickness, I was way above the 0.2mm I should have been. ARG. Noob error. Don't trust old eyes I guess. Once I got the height close, I actually made some PETG prints, still have issues related to those but I now know that I will measure my Z level settings and not trust what I see. Hard numbers were a life saver.
RE: Live Z calibration nightmare.
I'm late to the party here, but sounds like you are in good shape. Thanks for coming back and updating as well! It reminded me that I have calipers and should have been doing the same thing.