PETG finish changes mid print

If it were me I would just print the parts separate instead of messing with my profile settings. Other than a minute or two for the bed leveling, you (usually) don’t save any time by printing more stuff at the same time like you would with a Resin 3D printer.

That will be the next option.

So, bumping up the nozzle temp helped a tiny bit but not nearly enough. And here’s the thing…this is happening on single object prints and not just with multi object prints.
It’s hard to tell in the photo but the 1-2 layers at the transition point are glossy and the rest is more matte.


If you want my X1C PETG configs send me a dm with your email address. I tried to upload them here, but apparently only pictures are allowed.
PETG is working great for me and the dimensional accuracy is pretty good. I measured this cube at 20.05mm x 20.05mm x 20.10mm, so slightly more in the z axis but not too bad.

I ran a test with two parts, they both look fine. The lighting is not very great, but I didn’t notice any differences in the finish of either part at any layer. This is using 3yr old Amazon Basics PETG which is now sold under the Overture brand.



What model is that. Looks great

It’s called Om Nom. I honestly don’t remember where I got it from originally, but I see there are a few different versions on Printables. One is already modified for multi-material, I might have to try that one. This one Printables has the same filename as the model I printed.

Thanks, i can see a busy weekend coming

That’s a great observation and explains so much!!! Thanks for sharing, Duane!
Best,
Stu

It normally doesn’t bug me to have the sheen change in the print, but if you want it to not change, set the speeds to be consistent all the way through the print. As speeds go up, I find the print gets more matte. Someone did some tests and found that extra temperature helps to mitigate it as the speeds go up, but that might be difficult to recreate for you. So I suggest slicing it and then checking the slowest normal speed (meaning super slow over hangs and what not can be disregarded). Once you see the speed the bulk of the print is being done at, set the max speed to that. That will keep the speeds and finish very consistent.

Many times you can look at the slicer’s speed preview and see layer for layer where the speed changes along with the matte look.

This is certainly correct. The best results I’ve been able to get came when I increased the nozzle temp by 10C and slowed down the printing on the smaller, upper part. It came out acceptable, but still not really where I’d like it. In contrast, when I decreased the temp a little bit the transition was much worse. At this point it is what it is and I’ll either live with it or print the parts separately.

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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 “Min Print Speed” to 60 mm/s or disabling “Slow printing down for better layer cooling” 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 “sizzle” or “pops” 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 “missing the boat” here on something??

So are you saying model design features has a large impact? Would you recommend unchecking the “slow printing down” 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 “Speedproblem”. To counter this, i have Set the ‘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 “cobwebbing” of filament across the interior… which came off easily with a fingernail scrape! Thanks Lucyna_Kushinada for your tip!

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