First layer is not squished enough, visible gaps... H2S

Bambu Lab H2 Series Troubleshooting
1

Hello all,

I got my first Bambu printer, an H2S, about 3 months ago and already have around 700 hours on it. Up until a few days ago, every print was absolutely perfect, with only minor extrusion multiplier adjustments for different filaments.

A few days ago I noticed the first layer was off — it looked like it was not being squished enough, with visible gaps between the lines. At first I thought it was just one specific filament, but then I tried different materials from different manufacturers and got the same result.

It looked very much like under-extrusion, even though I was using known-good profiles and had not changed anything.

Then I ran bed leveling calibration, both regular and high-temp. After that, I got 2 perfect prints with excellent first layers. On the 3rd print, the exact same issue came back: first layer not squished enough, with gaps between the lines.

I am not new to 3D printing. I have been printing for years and have built more than 10 Vorons, so I know that when the first layer is off like this, the rest of the print will also suffer. The following layers then show visible gaps as well, which makes the whole thing easy to mistake for under-extrusion.

What I have tried so far:

  • Ran bed leveling calibration to rule out an extrusion/extruder issue

  • Changed the nozzle

  • Changed the filament/material

  • Checked the 3 screws behind the nozzle, they are not loose

  • Tried different bed and hotend temperatures

  • Increased extrusion multiplier, but that does not really fix it unless I push it to the point of obvious over-extrusion

  • Printer is clean overall, including the bed and the nozzle wiping pad

Oh and yes, i am using hardened steel nozzle 0.4mm standard flow. Read somewhere Hardened steel nozzles are known to have issues with Z offset….

Any tips would be greatly appreciated.

2

You prob checked this but does the problem occur at only certain parts of the bed?

And no debris trapped just under the plate?

3

Yeah, cleaned everything, pretty consistent across the bed. Now thinking about it, i have not changed nozzle wiper silicone brush since i got the printer…. maybe, nozzle is not getting cleaned properly before the print resulting in Z offset being off…. and i do remember seeing “fluffy” like parts of the filament on the perforated steel plate for nozzle wiping….

Thanks

4

Surely the fluff gets throughly flattened during initiation… but definitely worth checking!

1 Like
5

I had a similar experience with my P2S. I’m not sure if this is relevant for the H2S, but what I found was that the small plate used to wipe the extruder tip (in back of the build plate) was slightly indented (very slightly). I removed it (be careful there are 2 spacers underneath), straightened it out, and now have consistent prints.

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6

I have exactly the same problem. I was in contact with Bambu Lab support and we tried everything. They recommended a hotend heating assembly. When it arrived, I replaced it and I still have the same problem. Did you manage to fix it and how?

7

I tried to straighten the small metal plate for wiping the nozzle, I still have problems, has anyone who has a bambu lab H2S been able to fix this and how? I even tried bed traming but it didn’t help

8

the problem was not hardware, i did high temp bed leveling and filament recalibration before every print (AUTO) and this solved the issue. no hardware changed or replaced.

9

I already did that and it didn’t help.

10

I’m getting this on my H2C. I returned it 2 days later for a new one, and the new one has the same problem but worse.

11

Maybe similar to this one?