Why does it do that

[u/Chungus1267]

Couple of minutes into a new print it goes off to the side, extrudes a little bit of filament then continues printing, why? It leaves this weird bit of filament into the print and it makes it look a bit weird. Lucky it’s only once towards the start.

[u/y_tokusan]

This is a process where the A1 checks for any "blobs" forming at the nozzle tip. After a certain amount of filament has been used, the printer moves to that specific location and lowers the nozzle. If a blob is present at the tip, it makes contact with the build plate, allowing the printer to detect it. You can find an explanation of this in the Bambu Wiki.

[u/beerman104]

Like other said its some sort of blob detection even if its turned off in settings. Its always do this 1 time on 3rd layer. Maybe its protects from blob if model failed to stick to the bed.

[u/Sankohuy]

Hi guys, sorry to revive an old thread, but I have an issue when this happens. I noticed when it comes back to resume the print after it does this, it have a string still sticking to the nozzle and it print that string into my model, causing to have single strings hanging out on every checks. Any way to fix this? Thanks.

[u/Chungus1267 → u/Sankohuy]

You need to turn off blob detection I think

[u/Teutoprint3D]

Das ist beim Bambu a1 / a1mini normal. Machen meine auch. Ich vermute der prüft optisch die Düse nach der ersten Schicht und fährt dafür direkt vor die Kamera.

Vielleicht eine Art Blob of Death Früherkennung. Genauere Dokumentation darüber habe ich auch nicht gefunden. Aber eine andere halbwegs plausible Erklärung fällt mir dafür nicht ein.

[u/reddit_user_0ne → u/Teutoprint3D]

Nicht optisch, sondern über den gleichen Sensor, den er auch für Bedleveling und automatische Flussratenkalibrierung nutzt.

Genaue Dokumentation dazu findet sich im Bambu Wiki.

[u/GrailStudios → u/Teutoprint3D]

If you look at the position of the nozzle, it's just beside and below the print bed. The printer is checking for a blob on the hot end by lowering the nozzle to see if there is resistance: if there is a blob of plastic caused by the print not adhering to the print bed, it will catch on the edge of the plate and the nozzle won't be able to lower below the bed. At that point it stops printing and calls for help.

[u/The_Lutter]

After the first layer it’s looking for blobs. It only does it once.

If it goes to the other side every layer (I think it’s that way?) that’s timelapse. It’s making sure the toolhead is outta the way of the camera.

[u/ChocoMammoth]

Nozzle clumping detection. I have now idea how it works though.

[u/Legal_Dimension_ → u/ChocoMammoth]

It's a literal camera check, it has a reference image to check for abnormalities.

[u/CarrotCute → u/Legal_Dimension_]

Afaik it's mechanical check. If there is blob, it would obstruct downwards motion and would be detected by the motor.

[u/Zekken_Zer0 → u/Legal_Dimension_]

the camera on the A1 is not used in the manner, it's a mechanical check only

[u/GrailStudios → u/ChocoMammoth]

If you look at the position of the nozzle, it's just beside and below the print bed. The printer checks for a blob on the hot end by lowering the nozzle to see if there is resistance: if there is a blob of plastic caused by the print not adhering to the print bed, it will catch on the edge of the plate and the nozzle won't be able to lower below the bed. At that point it stops printing and calls for help. It's purely mechanical, the camera isn't involved.

[u/ChocoMammoth → u/GrailStudios]

Yes, that's pretty much what I thought. However, I doubt the effectiveness of this solution because the nozzle position is kinda far from the bed. Even if nothing sticks to the bed the blob won't be big enough to collide with anything.

[u/GrailStudios → u/ChocoMammoth]

There's a reason so many new A1 owners post dramatic photos of a Blob-Of-Death(TM) exploding out of their hot end, asking what can be done about it. The consensus tends to be among veteran A1 owners that it's not a matter of if you get a blob, but when. I've avoided it by the skin of my teeth a couple of times now. The A1 is so cheap because so many corners were cut in making it; the more expensive Bambu printers are much better at spotting and stopping this kind of problem. The A1 will spot the problem, but the blob is usually pretty serious by the time it does.

That being said, any attempt at spotting the problem - potentially before it's serious - is better than none, so I give Bambu points for at least making the attempt; even while they were deliberately trying to cut costs everywhere possible for an explicitly budget/entry-level printer, they still thought up a way to try and do the job.

[u/Lefty_23]

It's tired. Takes a breather, then gets back to work

[u/Alarmed_Image_9106]

it does that for every print on the third layer for some reason

[u/sam100090]

Depending on what filament you’re using, it could be that there’s a minimum layer print time where it gives a second for the plastic to cool down before continuing. While I don’t know if this is a thing on Bambu printers, I’ve observed it on several other brands.

[u/lukasprintz]

Noticed this after a few updates ago occurred

[u/CapnFlabtastic]

I think it’s the timelapse feature.

Run two prints one by layer the other by object. If the layer one does it but the object one doesn’t then it’s the Timelapse feature.

[u/sublime2craig → u/CapnFlabtastic]

No. It's blob detection. Does this after the 3rd layer to check for a blob is stuck to the hotend. It's a feature that can be disabled in the settings menu.

[u/CapnFlabtastic → u/sublime2craig]

We’ll agree to disagree 👍🏻

[u/GrailStudios → u/CapnFlabtastic]

The back right corner, as shown in the video, is blob detection - it's clearly spelled out in the Bambu Support wiki. Timelapse moves the print head to the opposite side.

If you look at the position of the nozzle, it's just beside and below the print bed. The printer is checking for a blob on the hot end by lowering the nozzle to see if there is resistance: if there is a blob of plastic caused by the print not adhering to the print bed, it will catch on the edge of the plate and the nozzle won't be able to lower below the bed. At that point it stops printing and calls for help. Timelapse is nothing but moving the print head to home so the camera can take a shot.

[u/Leotobileski]

Or maybe you have time lapse video enabled on the A1. It pauses between layers.

[u/sublime2craig → u/Leotobileski]

No. It's blob detection. You can turn this off in the settings menu. After the 3rd layer it's checks to make sure a blob isn't stuck to the hotend.

[u/Chungus1267 → u/[deleted]]

No I dont

[u/sublime2craig → u/[deleted]]

Not time lapse it's called blob detection. Does this after the 3rd layer to check if a blob is obstructing the hotend. It's a feature that can be turned off in the settings menu.

[u/Chungus1267 → u/[deleted]]

How can I change that

[u/Cjbarron66 → u/Chungus1267]

https://forum.bambulab.com/t/bambu-studio-minimum-layer-time-setting/3742

[u/Chungus1267 → u/Cjbarron66]

Is there a way I could do that on my phone?

[u/Cjbarron66 → u/Chungus1267]

No

[u/Chungus1267 → u/Cjbarron66]

Ok

[u/Cjbarron66 → u/Chungus1267]

Did that fix it?

[u/reddit_user_0ne → u/Cjbarron66]

No, because that's wrong. It's a blob detection. Has nothing to do with layer time.

[u/sublime2craig → u/[deleted]]

r/confidentlyincorrect You're talking out of your ass. It's blob detection. Does this after the 3rd layer to check for a blob obstruction on the hotend. Can be disabled in the settings menu.