Minor errors in printing with PETG

Lexo_Al · July 28, 2025, 5:42pm

Hello everyone,

i am new in the Bambulab Community, with the P1S Combo.
First, im Impressed of the Printer in comparison with my old one.
Such fast, good Prints, impressive.

But i have only a few minor issues with my prints.
I print almost only PETG. With PLA i dont have such problems.

It seems like little gaps or some type of too little flow of material, or maybe too much?

I had already done the calibration, currently i have a K-Factor of 0.020.
In the calibrations it says more like 0.030, but with this settings the print do not stuck on the plate anymore.

In my opinion the print is not that bad, but i am sure this could be get better with improved settings…

I put some pictures of it in this post, i hope someone could share some ideas/settings down here, that i could try.

The filament that i use: SUNLU Rapid PETG

The Picture with the black object was printed with some Creality PETG, i would say this could be slightly better… It happens more with bigger objects.

By now i only set the upper shell layers up to 7 and the infill to honeycomb. The other Settings should be original.

Thanks for your help,
Alex

BR34D_D0G · July 28, 2025, 6:59pm

ah i see. i have no idea what to do because i am new too. Good luck with it!

RocketSled · July 28, 2025, 7:05pm

PETG is one of the harder filaments to get to print well. It like to “string”, and the stringing tends to build up on the nozzle until it eventually gets deposited on the print someplace. If where it gets deposited is wall, it will leave a visible defect around that blob.

Need to do manual flow and PA cal, possibly also a temp tower cal. And I don’t see anything about drying the filament. Any of these things might explain the problem you’re seeing. You’re going to have to work through them all to see which.

blchandl2 · July 28, 2025, 7:23pm

In addition to @RocketSled recommended, you may need to slow things down a little. PTEG does not like to print as fast as PLA. I have not used SUNLU Rapid PETG so I don’t have any settings to recommend. I usually start with a Generic PETG profile and perform pressure advance and flow ratio calibration (in that order).

Lexo_Al · July 28, 2025, 8:24pm

Okay, thanks guys. Ich will try to do some calibration again.

I took the Bambulab PETG HF profile, changed the temperature to the Sunlu recommend and renamed it.

With the “Generic PETG HF” Profile the Printing was very slow, more than twice the time than with the Bambulab profile.

I thought it would be maybe a settings issue, the Speed was identical with 200mm/s in both profiles.

I could not figure it out, why this profile is that slow.

I do not dry the filament active. It sits for a few days in my AMS.

Maybe I will take this heating box from creality to dry it active in the future.

For now I will check your tips and do some testing with the flow, speed and calibration…

Olias · July 28, 2025, 8:37pm

I see several issues with your output. For now, try these settings I use for Elegoo Rapid PETG and share your reprinted samples so we can help further. While optimized for my purposes, interchangeable parts - they may not suit your preferences.

Lexo_Al · July 28, 2025, 8:54pm

Thank you for the profile! Which speed do you print with?

I will print the same object again and post new photos!

Olias · July 28, 2025, 9:04pm

I perform all my calibrations with standard speeds.

Lexo_Al · July 29, 2025, 12:07am

Hello Again

I tested the profile from @Olias.

I would say its way better now, thanks for that!

But this one corner is still the same, any ideas?
The top layers are good enough i would say.

I will try another Print later, where i increase the K Factor a bit. Maybe 0.025, 0.030 was too much.

Thanks.

Olias · July 29, 2025, 1:58am

If you’re referring to this segment, my guess is that you’re exceeding the max volumetric flow for your filament. Moisture in the filament is the most likely culprit but you can tweak the profile to get some - not a lot - but some relief.

I’m assuming you either don’t use Orca or aren’t on Beta 2.3 of Bambu Studio. Orca has had built-in calibration tools for over a year, including max volumetric flow. BS just added this in Beta 2.3, but I moved to Orca permanently and deleted Bambu Studio after Bambu’s January stunt with Bambu Connect and their forced privacy compromise under the false flag of “security.” Orca has always been five or six steps ahead of BS anyway. Here’s where that Calibration tool that will help you calibrate max flowrate in Orca, I believe I also saw it now in BS Beta 2.3:

That tool generates this model:

Tutorial: volumetric speed calib · SoftFever/OrcaSlicer Wiki · GitHub

Max volumetric flow (unlike flow rate) measures how fast filament can flow at max temp and max nozzle speed. The rainbow effect in the above picture shows increasing speeds. You know you’re exceeding flow when it looks like this and that measurement point is what you want to put in the filament profile:

Or, in your case:

Once determined, enter that number here:

If you don’t use Orca or BS 2.3, try this MakerWorld test model. It varies G-code speed similarly:

(I haven’t tested it since I use Orca.)

NOTE: Calibrating Max Flow Rate is not a substitute for drying filament.

Even if this helps with corners, dry your filament. No dryer? Use your build plate and the cardboard box it came in:

Here’s my P1 setup (yes, I overdid it with a fan and hygrometer):

Weigh your filament before and after drying.

Moisture may not be the cause, but weighing confirms it. Elegoo PETG’s cardboard spool alone can hold 4-6g of water. If you lose 6g, it may have been the spool, but now you know it’s dry.

How to confirm: weigh every 4-6 hours. Flip the spool every 12 hours over 24 hours using the printbed method (≈60°C). Closing the box can increase heat but risks warping one side of the spool.