Speed/Flowrate exceeding limitations over object geometry (bug?)

Hey guys, I’m trying to print at 20mm/s throughout the ENTIRE print, other than support. I’ve limited pretty much every speed setting I can in every setting except for acceleration values and travel speed. For context, I’m printing to get the clearest finish possible, so speed needs to be low.

Here is the 3mf:
clear vaccum part.3mf (114.7 KB)

Here is the issue:

Before speed change g-code:

After speed change g-code:

My speed settings:


Flow also looks really wonky:

Flow rate goes higher than my max flowrate as well:

Not sure if this matters but my cooling is all off. The fans will cloud the print. (Clear filament)

My guess is it has something to do with the hole ending, but I still can’t seem to find the issue or setting to change. Is this a user error or a bug?

I’m not sure what the actual problem is. But if you want the best quality print you can get, you want to crank those accelerations way down. It’s the energy from the accelerations that rattles the mechanics and induces small positioning errors that mess up the surface quality.

2 Likes

Attach 3mf please, it’s unclear

The “wonky” flow you showed is normal for scarf seams, but being above declared max isnt

RocketSled, I will change the acceleration values, thanks for that.

Bullocks, I will reply with the file and edit the original post.
clear vaccum part.3mf (114.7 KB)

Steps taken: Taking your file, hitting slice, going to preview, selecting speed

??? Maybe time to reset some things in your slicer. It gave warning of custom gcode in machine profile that I didn’t analyze.

Orcaslicer 2.3.1-beta nightly 9/22/2025

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I’m using bambu slicer 2.2.2.56

I am using slightly modified machine gcode copy pasted from this:

Do you have any suggestions as to what I could reset that could fix the problem?

My only guess is that the various “0”'s you have in some of the settings are triggering “0 to disable this feature” logic in some sort of nonobvious way. 0 Layer Times for example. Good luck!

Thanks for the suggestions, I’ll keep trying stuff!

So I didn’t figure this out at all. I’m probably more confused after fixing it. But I found a solution if anyone else has had this. Pretty much turn off “Slow down for overhangs” slice the plate, and it’s fixed. You can even turn it back on and slice it again and it will work.

Removing, readding, and reslicing the part will reproduce the same issue, and can be fixed by changing the setting like I described. Will definitely be sending in a bug report to bambu.

When I want to go slow I stopped mucking around with all those setting changes and just change maximum volumetric speed to something around 6.

I’ve tried this before and unfortunately it doesn’t work. The speed still changes mid layer and the max volumetric speed is still ignored.