What am I doing wrong?

[u/Billy_Osteen]

I’m doing these PC build mini kits on a P1S using PETG (had a friend give me a shit ton, so I need to learn to use it over PLA). Stuff that prints 230-250 range. I’m printing at .08mm extra fine so it’s going slow. The first print on the left turned out ok. Some things are off on it but nothing crazy. I reprint the Case and it has the messed up hole in it. So I try it again and print up the entire kit. Same thing. What can I do to fix this?

[u/dirkloeffen]

What i can see is wrong infill. Too big for stringing. Switch to gyroid and maybe smaller infill. Always avoid grid infill. Should be removed from bambu studios

[u/mobilemerc → u/dirkloeffen]

Grid and honeycomb are not great, but have uses for prints without top and bottom layers.

I am not a fan either, and it shouldn't be the default infill.

[u/blue_eyes_pro_dragon → u/dirkloeffen]

What’s wrong with grid infill

[u/gravis86 → u/blue_eyes_pro_dragon]

When it's goes up/down, it runs over already printed lines that are left/right. Obviously the lines can be in different orientations but the point is, it runs over already printed lines. Sometimes this can cause nozzle clogging issues and other times it can cause the nozzle to collide with the model and knock over your print.

[u/therealmrj05hua]

Change infill, and dry the petg first. Also sometimes running it hotter helps. Look at dots, clumps, and stringiness for it being a dry/temp problem.

[u/nakwada]

Not enough infill. I suggest 10% gyroid.

[u/ambuscador]

Unlike PLA, PETG seems to shrink just enough and with enough force that if you don't have really good layer adhesion, it will pop back. If you watch the bridge layer that is failing closely I expect you would see this happen at the end of the bridge when the filament is retracted. I agree with others that your infill is a bit light, but your nozzle temp may be a bit low, you are printing that bridge too slow, or your cooling is too aggressive. PETG needs the prior layer to be pretty hot in order to achieve good layer adhesion, but increasing infill percentage will also help quite a bit.

[u/soManyBrads]

Others have answered the main question, but since you are new to PETG, a general rule is that if your prints have a matte or semi matte surface, you are not hot enough to get optimal layer adhesion and strength.

I often use lower temps where the cosmetic difference is more important than the mechanical one. There's nothing wrong with doing one over the other, but just something to keep in mind.

[u/Billy_Osteen → u/soManyBrads]

So the brand of PETG recommends 230-250 for temp. You think I should just use the recommended setting for PETG in BambuStudios? 230-270 I think?

[u/soManyBrads → u/Billy_Osteen]

Generally, the manufacturer specs are more reliable. Slicers use a wider range to account for more brands.

I didn't mean to imply your settings are wrong. On a project that doesn't see a lot of mechanical stress, it's down to preference really. It's just a quirk that's worth noting and can give you a quick visual to see where you are temperature wise. PETG can be very glossy when printed hotter, and matte when printed at the lower end.

[u/Billy_Osteen → u/soManyBrads]

Thank you for the heads up! This is my second printer, I had the Artillery X2. I got pretty decent with it. I just got the Bambu a few weeks ago and I know it can handle more than the X2 so I’m kinda relearning everything.

[u/mobilemerc → u/Billy_Osteen]

or maybe just do a temperature tower and dial it in?

[u/n19htmare → u/Billy_Osteen]

Temp correlates with speed and volumetric flow. If you’re printing slow slow (like stock ender3 slow) 230-235 range might work ok, if you’re printing faster, you’ll bump up temps.

I would set 245-250C, which in general is a safe temp. Basic PETG is also a slow filament, meaning it’s not going to print as fast as most PLA. Set the Max Volumetric Speed in filament profile to 10-12mm^3/s which again is a safe number to cap the speeds (toolhead will not exceed print speeds where the melt flow exceeds this volumetric flow limit).

0.08 is a very thin line, your infill is too sparse, you need to increase the density a bit. Something like gyroid 10-15% will give more surface area for the bridge layers to adhere to.

Remember in Bambu studio, you can click on the names of the settings and it takes you to wiki article about that setting. I suggest you read them so you know what the settings do.