Ceiling clearance violation

#31112 (CORE One) #35112 (CORE One L) #36112 (CORE One INDX)

Relevant for

CORE One
CORE One L
CORE One+
CORE One INDX
9 comments
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What happened?

The Prusa CORE One/+ and CORE One L are CoreXY printers with a chamber. In some particular G-codes, especially customized commands, an upward movement after a downward printer movement might be programmed, but this carries the risk of a collision between a printed model and the chamber ceiling. 

In that case, the printer shows the warning message "A movement command risks causing the model to collide with the ceiling." before printing. 

Error name: Ceiling clearance violation

Error code: #31112 (CORE One) #35112 (CORE One L) #36112 (CORE One INDX)

How to fix it?

Before proceeding with printing the file, it is recommended that you double-check your printable file to ensure that no upward movements are programmed or expected after a downward print movement. 

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6 comments

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andrewmzhang
•
At the time of writing, the “Ceiling clearance violation” behavior is hard-coded into Prusa Buddy Firmware via the Z_CEILING_CLEARANCE macro, which is set to 100 mm. The check is implemented in the check_ceiling_clearance function. If I’m understanding the check correctly, the printer cannot perform a downward Z move (i.e., raising the bed) of more than 100 mm at any point during the print.

I think this implies that, when printing sequentially, you cannot print an object taller than 100 mm unless it is the last object in the print sequence.

I feel like a basic PrusaSlicer check that looks for tall structures in a sequential print could mitigate a lot of headaches here. Prusa should also explicitly state the 100 mm clearance limit on this support page.
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BMC
•
I too have found the warning to be problematic during sequential prints. It's almost 11PM and I'd like to sleep. Instead, I need to wait to cancel the warning for a print I already know will be fine.
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MarkusA380
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Please add a feature to disable the check and also improve the calculation as currently it will hit this warning for models that aren't tall enough to hit the ceiling.
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michele m
•
Your feedback will be collected but please consider that, in specific circumstances, an even only ~17 cm tall print may hit the top panel in case of CORE One (distance between nozzle and top panel) while ~3 cm may be sufficient to hit the X-linear reail (distance between nozzle and top panel), when the bed moves all the way up to the nozzle.
This is a SAFETY feature, and safety is never enough, so I can't tell for sure if our developers can make it optional. However, you may discuss this suggestion with other advanced Open Source community members in our GitHub space.
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3drick
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If safety is never enough, then people should not own 3D printers in the first place.

Honestly, users should be able to disable this safety "feature", or be shown how to disable it in prusa knowledge base. As another user pointed out, it makes sequential printing of tall objects impossible. It made me feel like I was dealing with some pre-configured toy and not the professional machine I thought I bought.
EDIT: Turns out I could circumvent the issue by adjusting extruder clearance hight in PrusaSlicer>>Printers>>General
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zdzd
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I also consider the inability to adjust the limits for this message to be a pointless foul.

Sequential printing is used specifically so that someone does not have to sit at the printer all the time to operate it. The fixed limit for #31112 completely destroys this function.

Průša relies on the possibilities of community modifications, but does that not apply to this parameter? There are many modifications that place the top cover at a different height, or even remove it completely. Then the ability to adjust the height value for activating #31112 is absolutely necessary. Without it, sequential printing basically loses its meaning. Even though the shape of the extruder is very favorable for it...
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Atrica3D
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Seriously. This needs to be adressed. It basically makes sequential printing impossible... If youre not right there to accept the message to continue printing, the nozzle will lose all pressure, and leave the first layer of the next object empty, because all the filament in the nozzle has seeped out...
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Kevin Brown
•
I'd like a way to disable this as well. I know what I'm printing, and there is no issue - but when printing sequentially, I get this error and have to confirm for each taller part. I'm using MMU3 cover, so I have extra clearance over the bed. My parts do not collide with the ceiling.
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