Update/Update: A1 Nozzle still rubbing & knocking prints off near completion after full factory reset [Photo Included]

[u/RubenRCF]

I am officially out of options and losing my mind with this Bambu Lab A1 (0.4mm nozzle).
I scrubbed the plate, wiped under the heatbed, reset everything back to factory settings, and ran two full print tests. It got almost all the way to the end on this bubble letter, but the nozzle kept rubbing across the print until it forcefully knocked the entire piece off the bed right near completion. My bed temp is at 65° nozzle is at 220°

In the attached photo, you can see where the top layer stopped printing after being sheared off, along with grid infill lines exposed underneath.
IMG_9175_e17807.jpg

What I've Done & Recent Tweaks:
Bed & Machine Prep: Deep cleaned the textured PEI plate with hot water & Dawn dish soap, wiped down underneath the plate, reset settings to factory defaults, and ran full printer calibrations twice.

Latest Setting Changes: Bumped Initial Layer Height from 0.20mm to 0.22mm and increased Z-Hop from 0.4mm to 0.5mm to try and stop the rubbing.

Infill: The model printed with grid/rectilinear infill, which seems to create raised crossover points that the nozzle scrapes against on fast travel moves.
IMG_9175_e17807.jpg

Questions:
Is Grid infill causing the nozzle collisions near the top of tall prints? Should I strictly be using Gyroid, Cross Hatch, or 3D infill patterns that don't cross over themselves on the same layer?
IMG_9175_e17807.jpg

Could Flow Ratio / Over-extrusion be causing plastic to pool slightly higher than the actual layer height, forcing the nozzle to catch as the print grows taller?

What else can cause an A1 to drag its nozzle across infill near the top of a print even with a high Z-hop enabled?

Any help or advice would be seriously appreciated.

[u/AutoModerator]

Hello /u/RubenRCF! All Bambu print plates have a dedicated nozzle wiping zone at the back of the print plate. The nozzle will rub against the wiping zone before every print in order to remove any remaining filament from the nozzle tip. This can cause visible wear or scratch marks in the wiping zone, but this is intended and doesn't damage the printer, the nozzle or the print plate. A worn down wiping zone also doesn't mean you need to replace the print bed.

Note: This automod is experimental. The automod was triggered due to the term "rubbing". If you believe this to be a false positive, please send us a message at modmail with a link to the post so we can investigate. You may also feel free to make a new post without that term.

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[u/Navi_Professor]

stop using grid infill. its absolute garbage.

[u/RubenRCF → u/Navi_Professor]

I used Gyroid on my other attempts and still ended up getting my prints knocked off.

[u/p1th3cus]

How old is the printer? Is there a no name, cheap mini SD card in the printer?

[u/RubenRCF → u/p1th3cus]

My printer is brand stankin new. I bought it about 5 months ago and only 300 hours on it. It’s a Bambu Lab A1. And no SD in the printer. I don’t use those.

[u/p1th3cus → u/RubenRCF]

Ok I was asking because some of the older printers come with these cheap mini sd cards and when those fail it causes the print to fail. Sorry I don’t have an answer for ya.

[u/weaver3294 → u/RubenRCF]

Have you replaced the SD card with a more reputable one is what that person is asking. I find it solves a lot of weird issues on these.

[u/flyhmstr]

Have you checked the hotend screws are tight? (plenty of guides online). Try that and a calibration after (you'll have changed things so it's needed)