Threaded screw - will this cause an issue?

So I have had my a1 mini for a little while now & have so far replaced the part fan + filament cutter and yesterday cleaned the extruder gears. (along with normal lubication each month etc).

When I was replacing the fan I noticed that one of the screws was stripped (number 4 on the image):


(taken from Part Cooling Fan Replacement guide - A1 | Bambu Lab Wiki)

All the other screws tighten well & hold well, this one goes to a certain part and then just spins… not getting tighter or looser.
I can’t see how this has happened as I have only undone it once (for the part fan replacement) and then it was like that on re-tightening.

So the question is - does it matter?
I am unsure what that attaches to and therefore if it is not 100% tight will it causes any issues?

I am currently trying to investigate & resolve some weird PETG banking issues and wondered if that might be a potential cause…
(banding I am talking about):

Since that photo I have:

  1. Recalibrated the extrusion modifier - it was set to the Bambu PETG HF 0.94 standard & running the full calibration ended on 1.0237…
  2. Cleaned the extruder gears
  3. (not connected) but replaced the filament cutter as well
  4. Tightened the 4 screws on the back of the heating block (now they can come lose)
  5. Modified my profile to use 30mm/s minimum for overhangs - as believe that can cause some weird layers after a hole / gaps in another part of the print. - see [SOLVED] Bad quality when printing PETG
  6. I have not done the bridging mode changes yet.
  7. I have re-dried the filament (Bambu Grey PETG HF) for 10 hours at 65c in a food dehydrator - the ambient humidity in the room is on 40% at 22c… but wanted to rule out any water.

Sorry for a ramble on why I am bothered about the screw… but wanted to explain why I am interested if a new extruder head would be needed?

Attached is the result of printing post doing all of the above - to be honest it is acceptable for the usecase (outside PETG holding down a BBQ cover), but it stands out and I would not want to give to anyone based on its looks.


The model ( and therefore plates) I am printing is - C-Klemme Schraubzwinge von S-XXL by DGs 3D-PRINT - MakerWorld

The PETG 0.16mm 4 wall version.
I have had to modify the plates for the a1 mini.

For the threaded part I have manually configured that object as :


and added a brim.

Global - Apart from moving to honeycomb ( as thought Gyroid could be the proble) and tweaking the bridge direction (to reduce the bridges).
I have made the following modifications:
image
image
image
image

I just printed a calibration cube, just to see if I have large ringing etc.

Interestingly there is a layer issue part way up… I guess that would indicate I might have something on the Z axis that is causing it?
I also get a weird “pull” in on the first few layers, where it seems that the material is smaller at the bottom than at the top.




So I have run Z wobble test by SavageLau - MakerWorld

But moved the filament to a different AMS unit (spool 3 rather than 4)… and this gave a perfect result - no layer gaps / buldges & uniform the whole way.

I am therefore wondering if part of the issue is a faulty AMS part…

Ok further testing completed… as I do think it is the filament.

I have printed (using orca for both) using esun PLA+ (standard profile) and the PETG HF filament that was used above today the orca cube.

On all images the dark grey is the PLA+ (eSun) and the light grey is the PETG HF (Bambu labs)
Both work - i.e. the thread fits nicely, but neither looks great
The Z surface on the top is fine on each as well. But the PETG has very bad lines around key changes on the cube. i.e From the top of the Y., the top right of the X etc.
Layer lose on the top right of the orca
The PLA+ also shows some, but they don’t “stay” for as long.

Any help to try to resolve these, would be amazing :slight_smile:





I don’t know if anyone is following this, but have been playing with the profile for the pla and turned off the slow down for cooling option



Well not perfect it’s a huge improvement.

There is still some ringing in the print.
I might try removing the tpu feet and running the calibration again and seeing if that removes some of it.

But weirdly having it run faster makes the printer better… it was bucking at 200mm/s.

I’ve now tried the PETG HF on bambu studio with the change to

With no other changes… this is night and day difference.

I am sure I can keep tweaking, and I am a little annoyed by the resonance on the print… but will try some normal models and see if it appears or not.