I needed a really weak excuse to buy an almost $400 thermal camera attachment for my phone, so I rationalized that taking some shots of my A350 print bed could help give clues to bad bed adhesion on the outer areas of the print bed. I found that the temp variation between the middle and outside parts of the bed is too small to matter, and therefore has nothing to do with my bed adhesion woes
But now I have a thermal camera
Here’s me heating the bed to 80°c withOUT the mat.
Here’s 55c and 80c right as they got to temp. Note that the front of the enclosure is slightly cooler than the back because the front door is wide open. I moved the bed back a little to try to mitigate front/back variation. I’ll take the next photos in 10m, then 30m and try to snap it as soon as I open the enclosure door so it doesn’t lose too much heat at the front.
+15m, then +40m exactly the same. I saw the front corner hit over 66c right as I opened the door but couldn’t get my tripod in place fast enough to catch it.
Wow, that’s actually really interesting. The common consensus seemed to be that the bed would normalize a bit after being hot for a while. This seems to show that at least the temp normalizes really fast, I wonder if the warping normalizes just as fast as the temperature.
It’s also a bit upsetting to see that ABS will be basically impossible to print at the edges of the bed, even if you try to let it sit for a while.
The warping takes a little time to normalize. 10-15 minutes is typically sufficient.
With some blue tape, or alternate build surface such as glass, you could use ABS Juice to print ABS material. ABS Juice is acetone mixed with ABS filament. There are recipes online for this. It is not compatible with the print sheet, hence the need to blue tape or glass bed.
I haven’t done it much yet, but I am prepared to. Having the enclosure makes a huge difference to keep the surrounding air temperature stable to prevent part warping.
I was considering getting one of those myself, but i was reading that they were not very good. It is nice to see someone having success with it on something i am familiar with, makes me reconsider.
Heat loss in the middle will always be less than at the edges, and less at the edges than the corners. Fixing this requires insulating the edges and corners so that heat loss is primary perpendicular to the bed. So you’re going to lose print area because of non-uniformity or you’re going to lose it with insulation (because the uprights are a fixed distance apart). Insulation would likely give you more area, but as the IR images show, you need to verify that your insulation scheme actually does what you want it to.
The oscillation you’re seeing is the result of the bang-bang type of regulation of the bed heater. The hardware would support a better control loop, but it’s never been written. There’s even PID control code for the FDM nozzle, but it’s not being reused for the same kind of problem with only slight variation.
I love the thing. I read about a bunch of battery issues, but haven’t had any myself. My fiancée hates that now I won’t put a steak down without making sure my pan is EXACTLY 425°.