Build plate not staying leveled?

[Nazulle]

I'm still very new to 3D Printing so i don't have much experience. I have a Rostock Max v2, and I was ale to get my first few prints to print successfully but now my printer isn't staying leveled. What is would do most of the time is that the nozzle would touch the build plate with almost zero(a very thin line shows) to no plastic being extruded. I'm not sure whats going on? This has been happening for he past couple of days and its starting to get on my nerves. And the night before it would be fine considering i have to keep calibrating it which is very time consuming. Is anyone else having the same problem or know how to fix this?
Also, i tried calibrating it both from the software and using the screws but they only temporarily work until it gets unleveled again.

Thanks in advance,
Nazulle

[Nazulle]

By the way, I am using Hatchbox Blue ABS with glue on a heated bed set to 80 degrees. So the prints should adhere pretty easily. Printing at 20mm/s in 215 degrees for the hotend. I'm using Matter Control 1.2

[bvandiepenbos]

make sure your bed is heated up when calibrating. hot end also.

are the screws that hold bed down tight, but not extremely tight, if to tight I think the heated bed can warp when it expands/contracts with temperature change if it can not move slightly on screws.

also look for loose screws holding hot end to platform.

endstop switch mounting screws tight?

endstop adjusting screws loose?

[Nazulle]

make sure your bed is heated up when calibrating. hot end also.

are the screws that hold bed down tight, but not extremely tight, if to tight I think the heated bed can warp when it expands/contracts with temperature change if it can not move slightly on screws.

also look for loose screws holding hot end to platform.

endstop switch mounting screws tight?

endstop adjusting screws loose?

I didnt think both nozzle and heated bed had to be heated up when calibrating. What does this affect?

The bed screws seem to be fine but im going to check again after this print is finished, same goes with the screws holding the hotend but those should be fine too.

The endstop switch mounting screws would be the ones holding the switches to the printer right? If so, those are not wobbling.

Im not sure what you mean by if the adjusting screws are loose. They arnt wobbling either if i move them, but the screw on the Z axis is noticeably higher than those on the X and Y axis is this is any help.

[Polygonhell]

I didnt think both nozzle and heated bed had to be heated up when calibrating. What does this affect?

It changes the distance to the bed by enough that if you calibrate cold your hotend will hit the bed hot.
But more than that, because the heated bed PCB will warp as it heats, it will also mess with the tower calibration because the glass will tent to stay flat on the warped bed.

[bot]

I didnt think both nozzle and heated bed had to be heated up when calibrating. What does this affect?

It changes the distance to the bed by enough that if you calibrate cold your hotend will hit the bed hot.
But more than that, because the heated bed PCB will warp as it heats, it will also mess with the tower calibration because the glass will tent to stay flat on the warped bed.

In my experience, this is not true at all. I recently calibrated cold just to see how it would work, and it was perfectly fine. Though, I was using feeler gauges, and use buildtak so I need no "squish." If on glass and squishing, I could see how it might make contact.

[Polygonhell]

I didnt think both nozzle and heated bed had to be heated up when calibrating. What does this affect?

It changes the distance to the bed by enough that if you calibrate cold your hotend will hit the bed hot.
But more than that, because the heated bed PCB will warp as it heats, it will also mess with the tower calibration because the glass will tent to stay flat on the warped bed.

In my experience, this is not true at all. I recently calibrated cold just to see how it would work, and it was perfectly fine. Though, I was using feeler gauges, and use buildtak so I need no "squish." If on glass and squishing, I could see how it might make contact.

I use a feeler gauge, usually a 0.004in one, I usually adjust the final offset by 0.1mm for the size of the feeler gauge, so 0 should be 0.

I used to recommend doing the radius calibration cold, since it's all relative to the center point anyway, but I see variation when it's heated and worse it's different depending on how the glass plate is clamped. Now I do have a V1 Onyx bed, the newer variants maybe better.

My math says that for something like the stock hotend you should see a change in length of the hot part of the hotend of about 0.1 - 0.2 mm which given the layer heights were dealing with is significant. Thermal linear coef of expansion for aluminum is about 22e-6 M/MK so if were looking at about 4cm of the hotend actually hot and a change of about 200K then we have 200 * 22e-6 * 0.04 * 1000 = 0.176mm of expansion.

[bot]

I agree that there will obviously be some expansion. And also, I agree, that build plates can warp and vary when heated. I'm not sure if it would be .1-.2mm, as I would have certainly noticed that. There is no need to speculate on this point, as we can simply measure it. I have a 56 hour print going right now, but when it's done on Sunday I can measure the difference. It would be interesting for you to measure the difference for your setup and compare.