Hi all, after several comments on various threads regarding the large bed on the K2+, and it’s shape changing with temperature, I thought I’d do some testing. I ran a mesh calibration at four stages; first is after leaving the printer turned off for a week (22degrees ambient), then bed heated to 50degrees and left for 5 minutes to stabilise, then raising to 100degrees and again leaving at that temp for 5 minutes, then after leaving at 100degrees for over 2 hours. Results are interesting (I took a screenshot of the klipper tune page after every calibration run.
Bed cold (22degrees):
Yes, the aluminum of the bed will grow or shrink with the temperature of the bed. Always create a mesh at the bed temperature you will be printing at.
With your meshes it looks to have the four screws holding the bed are too tight and not allowing the bed to flex out and causing it to taco. One screw should be tight and the others snug to allow growth and shrink.
Update - I’ve spent some time getting my bed level - I inserted two shims under the bed, between it and the metal cradle, and adjusted the spring-loaded corner screws until it was as level as I could get it. Results are as good as I could have hoped. This is without using any tape - just a pair of shims (short large bolts filed to size) wedged between the bed and the cradle. The pics are of mesh runs without the PEI plate in place, as I wanted to get accurate measures of the bed itself without the plate skewing the results.
The results show more clearly the warping due to high temperatures, but with the bed now levelled, the variance is much less, and able to be handled by the firmware without affecting the first layer (I hope!).
Someone should try a thin glass sheet between the bed magnet and build plate. The extra mass will require a longer heating time. If the magnet still works, maybe this will be the best of all worlds?
hello, i have tried lvl the bed with only the knops. First picture is the default how it came out of the box. Not really that bad but when using the hole plate on the high points the nozzle is just to close its not getting corrected enough. After some playing around i could not get the front of the bed any lower without messing up the rest of the bed. Then my wife had a idea and it worked a little bit. She gave me a clothespin i used the inside you can see in the picture the. Going from 0.5530 to 0.3630 then only the clothespin to 0.2750. this was all on 50c. Just wanted to share wath i have done maybe someone can do something with it.
