[Feature Request] Heated Bed and Nozzle Calibration


#1

I have seen significant differences in calibrations when the bed is cold versus when the bed is hot.

Please either add heated bed and nozzle temperature controls to the calibration screen OR add a Heated Calibration that first takes the bed and nozzle set temperatures from the user and then starts calibration when those temperatures are reached. If you feel that you must, you can display a warning that this mode is only recommended for advanced users who will be responsible for their own safety while these temperatures can burn them if they come into contact with heated components.

Either way, I’d really like to not have to “start a print” and cancel it just to have the bed warmed up enough to do a good calibration. I have prints that will not stick no matter what I do when I print on a bed that was calibrated cold. The very same prints will stick every time when I calibrate with a heated bed.

About 15 seconds of this video at this point will show you how much a hot plate flexes as it goes through it’s normal heating cycles. Hot plates run on a duty cycle meaning that they reach their set temperature based on running for X seconds and off for Y seconds before repeating the cycles. As the hot plate cycles you can see the plate flex one way and then the other. The heated bed flexes a little bit when it heats up and I would like to calibrate it at the temperature of the print, but currently the controls do not make that easy without a work around. See this moment in the video for about 14 second: https://youtu.be/E2zS8MyvJxU?t=398 to see what I am talking about.

(Starting a print and cancelling it when it reaches the set temperature gets you “close enough” when calibrating even though the temperature is rapidly decreasing. Using OctoPi or the control software through a USB cable is another work around, but I really like just printing straight from the touch screen, so I would really like to see this be a touchscreen calibration feature.)


#2

I found that I needed to do a calibration print anyway. It wasn’t too bad when I was printing 0.1mm layers, but it was pretty bad when my son printed with a 0.05mm layer. To calibrate, we printed a single 0.05mm layer of https://www.thingiverse.com/thing:2125379 , and just tweak the calibrations values based on how the print looked.

With the 0.05mm layer height, we ran into issues with both failure to stick on one corner, and printing so thin that the layer tore when removing it from a different corner. This was already calibrated and mostly working for a 0.1mm layer. For the very thin corner, he even had to adjust the bed height with the thumbscrew, because the finest calibration step is also 0.05mm.

My 0.1mm layer prints are much nicer now too.


#3

That’s a fair point, but I’m not at that stage yet. I’d like to at least get a good calibration on the bed when it is heated to the temperature that it is printing at. Adjusting the screws by hand based on the looks of the print is a bit beyond me right now.

I’ve got pretty good 0.1mm layers going in petg. My only issue is a little build up on the nozzle by the end of longer prints. So far the build up hasn’t caused any major problems and from what I’ve read this is common with petg. I’ve had some success and challenges with 0.05mm layers, so I could see the bed affecting that was well.

Which calibration object did you print for yours?


#4

I understand where you’re coming from. For me, even with a pre-heated bed, calibrating with paper was adequate at best. I’m much happier with my prints after taking the time to do print calibrations.

I also discovered that it’s best to keep the bed covered (I don’t have the enclosure). Even a tiny amount of dust or oil on the bed would cause adhesion problems. I used to wipe the dust off with my bare hand – that was a bad idea. Even after cleaning my bed with alcohol, I needed to re-print my calibration test (https://www.thingiverse.com/thing:2125379) to get it completely clean. I could see the outline of the print on the bed after I peeled it off. So far, I’m exclusively PLA, but it cleans the bed fairly well even when it doesn’t stick.

There’s also a head impact mark on my front edge of the bed. It arrived that way. This is also the corner that gives me the most trouble. At the 0.05mm layer height, a few µm can make a difference.


#5

I have the enclosure. I can sometimes tell the difference in layers where I know I’ve opened the door versus prints where I haven’t. I usually only have first layer adhesion problems if I calibrated bed cold. I do use a thick 0.2 or 0.3 first layer setting. I did have warping on a thin shim that I printed but it was a worst case scenario print that I was using to test out some temperature settings.

I do try to avoid touching the bed. I haven’t cleaned it yet, but I do have an alcohol pad I can use. Hasn’t really been much of a problem. I do think the calibration should have a 5th point in the center or use a 3x3 grid. I’ve considered getting glass for the bed, too. A little pricey but I’ve seen stuff printed with a glass surface and it is quite nice.