Heatbed low temperature / MK4S - Core One+ Conversion
I just converted one of my 2 MK4S to a Core One+ with the Conversion Kit.
I had issued with the heatbed on the MK4S that I dismantled: the temperature was 52°C when I dialed in 60°C. This problem is now also showing in the Core One+ as it uses the same heatbed. I saw that there seems to be no calibration feature available.
There is no error. Selftest is just fine. But the temperature (measured with two different infrared thermometers) is significantly too low, leading to significant warping of larger PLA items (like boxes). I can circumference the problem by dialing in 75°C instead of 60° but I do not like these kinds of workarounds as updates in settings requires me to transfer this to the new Filament settings.
Anyone else experiencing this and has a solution? Thank you!
The temperature is supposed to be that at the print sheet/first layer interface, so:
Replace a previous print - a fairly large one, on the print sheet and then heat the bed. Wait for it to warm up then remove the print and immediately check the temperature underneath.
Any better?
Cheerio,
RE:
Thank you. Not sure if that should help.
- Do you say that the temperature is lower with nothing printed on?
- Shouldn't the print sheet temperature be 60°C if I dial in 60°C?
Also, the results were clearly visible. With large, box like parts (hollow, 2mm wall thickness), there was significant warping. When I set temp to 75°C no warping at all.
RE: Heatbed low temperature / MK4S - Core One+ Conversion
This is the same physical heat bed as the one that had a problem before? If so, it could have a bad/drifted temperature sensor. This might help- https://help.prusa3d.com/article/heatbed-not-heating-up-properly_2086
Also note that the tolerance is (if you can trust AI) +/- 15 C. Seems like a lot, but could be right. I love my IR thermometer, but you have to be careful with emissivity and calibration.
RE:
Thank you Conrad . The thermistor was replaced with a new one as part of the Core One conversion process. Plus I have two very different IR thermometers that differ only by 2K. And BTW, I do not trust AI 🤣. I don't have the tools for a proper temperature measurement. I found the temp being too low because I experienced warping which wasn't there before. Hence I checked bed temperature. But your link is great. I will do a couple of more tests. However it is a bit older and does not cover the MK4S nor the Core One.
RE: Heatbed low temperature / MK4S - Core One+ Conversion
Do you say that the temperature is lower with nothing printed on?
Yes, the polymer is a thermal insulator
Shouldn't the print sheet temperature be 60°C if I dial in 60°C?
Yes, under the print.
Also, the results were clearly visible. With large, box like parts (hollow, 2mm wall thickness), there was significant warping. When I set temp to 75°C no warping at all.
75°C is above PLA's glass transition temperature - it is very likely that the print sagged back to flatness but lost accuracy above...
The commonest cause of warping with an enclosed printer is a poorly cleaned build sheet - and for an experienced user that usually means a build-up of residues insoluble in the usual cleaning fluid so switch to something else for a rejuvenating scrub.
Cheerio,
RE: Heatbed low temperature / MK4S - Core One+ Conversion
75°C is what I dialed in. The temp measured was the desired 60°. The problem is that the heatbed is not performing as expected. It is not warm enough.
Once you are printing it is very likely to be too warm -
Replace a previous print - a fairly large one, on the print sheet and then heat the bed. Wait for it to warm up then remove the print and immediately check the temperature underneath.
Cheerio,