PETG finish changes mid print

I get very consistent glossy PETG by slowing outside walls to 60 or 50 mm/s - should have minimal effect on print time for most prints.

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This was the key, thanks. Now the whole part(s) come out with the same glossy sheen across the whole print.

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Glad you got everything sorted!

If I’m understanding correctly, I think changing the ā€œMin Print Speedā€ to 60 mm/s or disabling ā€œSlow printing down for better layer coolingā€ would also solve the issue, and allow you to use this preset every time you print with this filament.

New member here… and new owner of a P1P. I’ve printed several PLA models (starting with Benchy boat) using default settings, and all the PLA models have turned out excellent.

Now I’m trying PETG from Overture. I’m using the textured PEI plate. First try I selected generic PETG in Bambu Studio, and tried printing a coffee mug model with default settings. Horrible stringing and also very matte finish.

Notes: The room temperature is fairly cool at about 65°F. Room humidity is extremely low at 30% or lower. I am not noticing any ā€œsizzleā€ or ā€œpopsā€ from the nozzle, and no noticeable bubbling in the print, which I understand is hints of excessive moisture.

For the stringing I tried modifying only the Retraction Length filament Setting Overrides:
Length = 2mm

This seems to have helped the stringing quite a bit… not completely gone but acceptable. But the matte finish still looks bad and varies from slight splotches of shiny.

In an attempt to improve the shine I changed the following filament settings:
Flow ratio = 1
Nozzle print temperature = 265 (both Initial and Other layers)

Third attempt on the cup - at about 3/4 way up the cylinder, the matte finish began gradually changing to shiny.

The next change was focusing on slowing the print speed.
Printer > Other layers speed > Outer wall = 100
Filament settings > Part cooling fan > Slow printing down for better layer cooling (checked)

I’ve resorted to printing Benchy as a test after each change. The Benchy starts out somewhat shiny, but as the print progresses (above an imaginary waterline on the boat) the hull reverts to a matte finish again. The smokestack on top is a very nice gloss though.

HELP! What am I doing wrong, or am I ā€œmissing the boatā€ here on something??

So are you saying model design features has a large impact? Would you recommend unchecking the ā€œslow printing downā€ in filament settings?

I believe the first Benchy I printed had that unchecked… with no improvement.

I’m trying to achieve the surface results which 0x80O0oOverfl0w posted above. I’m using the same filament he used, but are there any specific settings I should be looking at which would help me get there? I would think a Benchy wouldn’t be that difficult to get that shine??

It is a ā€œSpeedproblemā€. To counter this, i have Set the ā€˜outer wall’-speed to 50mms.

IT helps to get much better quality.

I tried a new Benchy boat with this setting at 50mms… BEAUTIFUL! Now for the coffee mug test… again! I have high hopes!

Update: The coffee mug turned out really nice… very shiny with just very minor ā€œcobwebbingā€ of filament across the interior… which came off easily with a fingernail scrape! Thanks Lucyna_Kushinada for your tip!

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