A1: First layer / bottom surface suddenly looks rough

[HenryWinter]

Hi everyone,
I’m having an issue with my Bambu Lab A1 (12 montsh old) where the first layer / bottom surface started looking wavy, rough and uneven (looks like material is being “pushed” and leaves ridges/waves). This happens on larger flat areas and shows up as visible texture artifacts in the bottom surface.

Printer / Setup

• Printer: Bambu Lab A1
• Nozzle: 0.4 mm
• Slicer: Bambu Studio
• Plates tested: Cool Plate, Engineering Plate, Textured PEI
• Filaments tested:
  • SUNLU PLA+ (the filament where the problem started)
  • Bambu Lab PLA (used for comparison/tests)

What I see

• The first layer / underside looks inconsistent and wavy across the surface.
• The issue appears regardless of the build plate used.
• The problem persists even after calibrations and changing profiles/filaments.

What I tried already

1. Cleaned Nozzle
2. Switched build plates:

• Textured PEI → same issue
• Engineering Plate → same issue

3. Dried the filament and repeated tests → issue remained (felt even worse afterwards)
4. Flow calibration:

• Ran Flow Dynamics (automatic) and Flow Rate (manual) calibrations
• picked -5 and then fine tuning with -4
• Current flow ratio ended up around 0.914 for SUNLU PLA+ but the first layer still looks bad

Frankly spoken I have no idea on how to proceed… get a new nozzle? Any help would be greatly appreciated.

[teras]

I’ve been experiencing the same problem for the past 1-2 weeks. As a solution, I removed the hotend heater kit and tightened the bolts on the back, and it fixed the issue. However, since the problem is recurring, I’m now constantly removing the hotend kit and checking the bolts. I think I should replace the entire hotend kit.

[HenryWinter]

Thanks for the tip! I checked all the bolts, they were rock solid. I ended up disassembling the entire toolhead and putting it back together, but if anything, that just seemed to make things worse. I also cleaned all my build plates, played around with slicer settings, and tried a bunch of other tips for the first layer ripple issues.

So far, the only thing that actually seems to help is adjusting the Z-offset in the machine start G-code. At least with the textured PEI plate, I’m finally getting clean first layers again. Now I just need to figure out the right G-code snippets for the other plates.

[user_750836559]

Similar issue on my A1. Will follow some of these steps and see how I get on

[Kevin5]

I had the same issue. I replaced the heater assembly (the part the nozzle clips into) and now the issue is gone. I think it was how I had routed the wires when replacing some parts.

[HenryWinter]

After digging my way through half the internet yesterday, my conclusion is that there are various possible causes for the “first layer ripples” issue, but they all lead to the same outcome: the distance between the build plate and the nozzle is too small.

What ultimately solved it for me was manually increasing the Z-offset for all plates by 0.04 via the machine start G-code. I didn’t need to make any further adjustments.

This code has already been posted several times in the forum, but to save anyone who comes across this thread from having to search for it again, here it is.

The code is already adjusted for my printer, you might have to run a few tests in+/- 0.01 steps find the perfect offset for yout printer and built plates. For me it was adding 0.04, so I put Textured PEI to 0.02, as the default is -0.02, for all other build plates I assumed a default of 0.00, so I put them to 0.04.

;===== for Textured PEI Plate , lower the nozzle as the nozzle was touching topmost of the texture when homing ==
;curr_bed_type={curr_bed_type}
{if curr_bed_type=="Textured PEI Plate"}
G29.1 Z{0.02} ; for Textured PEI Plate
{endif}
{if curr_bed_type=="High Temp Plate"}
G29.1 Z{0.04} ; for High Temp Smooth Plate
{endif}
{if curr_bed_type=="Cool Plate"}
G29.1 Z{0.04} ; for Cool Plate
{endif}
{if curr_bed_type=="Engineering Plate"}
G29.1 Z{0.04} ; for Engineering Plate
{endif}