Bed level compensation / temperature - technical questions
Hello Members,
I've recently bought/cleaned/adjusted old MK3s that worked OK, until I wanted to print something that covers most of the bed - at one corner PLA filament does not sick to bed. Before digging into printing problems deeper, I would like to get some understanding of the hardware/firmware (firmware ver 3.14.1-8237) - could You please explain a few things?
1. How bed level compensation actually works? I assume that after measuring height at 9 points printer builds a map and uses it to adjust nozzle according to its position. However when doing first level calibration and also real prints I do not see any Z screws movement during first layer print. Is that OK, or I have a problem here? I do not expect the bed to be so flat.
2. When printer reports bed temperature 60degC, real printing surface temperature is ~51-53degC. I've red that there is no compensation/calibration for this available, and some errors are expected, but really about 10degC? My room is normally rather cold (~17degC) so it definitely makes it worse. Is there any "approved" procedure to fix it (beside setting bed temp higher in slicer)?
And one more thing about firmware update: is it possible to update firmware without overwriting calibration data? I'm asking because I consider recompiling firmware myself and maybe adding some "only-for-me" features, so making a "quick" update without ~30min long calibration process is useful.
Thanks in advance, Michael W.
RE: Bed level compensation / temperature - technical questions
Bed temperature and levelling may be an issue. As with any technology, you have to adapt to where you are using it. "Normal" is under the same conditions.
I print with an enclosure so many NORMAL comments change. You are printing in the open air where temperatures are much lower.
In my early days, at work, long before getting a 3D printer, I found that an enclosure, even a cardboard box was better than nothing.
Bed temperature is measured from the bottom of the bed. Any other method of measurement will give you a different reading
Silicone pads for levelling the bed is also a great
There are several possible causes of localised poor adhesion. Before making any hardware changes make certain the print sheet is completely clean. Look up the many threads here on cleaning.
The printer attempts to bring the top of the first layer level, some of this can be done by varying extrusion.
The exposed areas of the print sheet lose heat while those covered by the print remain hotter.
Cheerio,
RE: Bed level compensation / temperature - technical questions
Many thanks for replays, now it is more clear for me. It seems that problems are solved, and I'm just running a "test print" on almost all bed that looks OK (for now, about 10h left).
Steps done: Bed cleaning (I think it was the most important), increase bed temperature by 5 deg (just for testing) and adding noylock mod along with bed leveling, https://github.com/PrusaOwners/prusaowners/wiki/Bed_Leveling_without_Wave_Springs
https://plugins.octoprint.org/plugins/PrusaLevelingGuide/
The mod needs some hardware work and most likely it was not absolutely needed, but for me the point of getting Prusa is the ability to modify it :-).
Thanks again!