Temperature difference between center and edges of the heatbed
Hello,
As the title mentions, I noticed on multiple part prints that some had a tendency to come off the bed during printing, ruining the print. The affected parts are towards the sides/edges of the heatbed. I measured the temperature with an IR Thermometer and at 90 celsius, there's a 15-20 degrees difference between the center and edges of the heatbed. On temperature sensitive materials such as PETG and ABS, this is not good at all.
I have a MK3S+, powder coated textured bed. I don't print in an enclosure, but that's on my to do list.
Is this a known issue?
I have thought about some solutions, and wanted to know if anybody tried :
- move the thermistor between the center and edges to get a better average
- insulate the edges of the bed so they stay hotter
- or simply set the temperature a bit higher in the slicer
RE: Temperature difference between center and edges of the heatbed
The edges of the heatbed collect more fingerprints than the centre, this is the more likely reason for poor adhesion. Scrupulous cleaning is always worth trying...
Heat differential issues usually manifest as warping, especially on larger prints. If your workshop is particularly cold then MINTEMP errors become an issue too. An enclosure is the usual answer if these problems occur; a large cardboard box can be used as a temporary enclosure to test.
So: first try extra cleaning.
If no benefit, try raising the heatbed temperature by 5 degrees; but keep up the cleaning.
Cheerio,
RE: Temperature difference between center and edges of the heatbed
What Diem said, and a temporary enclosure if needed.
The Filament Whisperer
RE: Temperature difference between center and edges of the heatbed
@diem
Hi, I do wipe the bed with ipa before every print. Maybe I need to scrub harder. I'll try with higher bed temp as well.
I din't have any min temp errors. The room where the printer is is usually around 20-21 celsius, and there is no air draft.
I was really interested to see if the temperature difference was normal or if my bed was defective 🤔 .
RE: Temperature difference between center and edges of the heatbed
No a temperature difference is normal. It is with nearly every 3d printer on the market too. Tom Sanladerer did an interesting youtube via on it awhile back.
Its quite normal also to preheat the bed for 20-30 minutes before a print session to give the bed time to equalize its temperature if it bothers you or you are going to be doing a full bed print. Far better to spend a bit of time preheating than have a multi hour or day print have problems.
On the cleaning front you should read several of the posts on here about cleaning. IPA is not the best way of removing the the grease and oils that cause print adhesion issues. Taking your build plate to the sink and washing it thoroughly in plain detergent (Dawn/Fairy or similar) and very HOT water with a clean paper towel and then drying it with further clean paper towels is the single best way to actually remove oils. IPA will dissolve the oils into suspension and move them around. This often then leaves a thin layer of skin oils all over the bed. Detergent actually removes it.
I know the Prusa instructions say use IPA and do not recommend water but that's because the steel sheet is actually open through the coating as its porous. This can lead to rust forming, which is why Prusa don't recommend it, but only if you don't dry the sheet. If you place it on your bed and preheat then it will dry quite nicely and you wont get rust.
RE: Temperature difference between center and edges of the heatbed
@neophyl
Thanks for the info!
I did not see Tom's video about bed temperature, I should go watch that. I also thought pre-heating wasn't required as the heating element and steel sheet are quite thin. I thought heat transfer was faster.