Good day to all, I’ve been fighting a long fight with PETG on my Bambu P1S and I think I’ve been defeated. I’ve tried everything from:
*Changing heat bed and nozzle temperatures
*General calibration to calibrating flow dynamics and flow rate.
*I’ve tried drying the material, (Bambu PETG HF) to getting a whole new one from Creality; to see if maybe that would change something.
And all the solutions I’ve been seeing just tell me I should dry the material, but within 30 seconds of me opening the sealed filament; to me loading it into the AMS and starting the print I highly doubt moisture would affect the quality that much. I’m lost as to why it keeps doing this. I also tried a different material, Bambu PLA Matte and the print came out relatively fine (side by side comparison below). Any form of help would be appreciated.
Never assume that filament in a sealed bag is dry. If it is anything other than PLA, there is a 90%+ chance that it contains print-affecting moisture. In particular, the description for Bambu PETG-HF specifically states that it must be dried before use.
Follow the link below to dry your filament with your printer. If you have a digital scale, record the weight of the spool and then dry it until the weight stops dropping. THEN you will have dry filament.
Assume PETG is wet from the factory. I only trust a roll is dry if it comes in mylar and is from a vendor that has proven to ship dry before [Sirayatech comes to mind].
Your spires are melting likely because of cooling. Those are tiny objects, small layer times, and PETG will likely misbehave even worse if you blast it with fan. Instead of tweaking paramters first, try putting your model on a plate with a benchy, and print them both. The extra time taken to print the benchy will give the PETG time to cool before the next layer hits. If this alleviates your problem, you can half-ass a solution by printing 20 of your hats at a time on a plate [dial in retraction or suffer strings], or you can finetune your minimum layer time (in a number of diffferent ways, see filament->cooling tab)
If I had a dollar for every time someone posted here over the last two years claiming their filament was dry, or that it was “factory sealed,” or that they dried it for X hours so it must be dry…
So maybe it’s dry, or maybe it’s not. How do you know for sure? Even if it is dry, as a diagnostic step you still need to verify it. The only reliable method is to weigh it before drying and then weigh it after. If it stops losing weight at 60°C for PETG after 6-12 hours, you know it’s dry. If it never lost any weight, you confirmed it was dry out of the box. Either way, you gain useful diagnostic information you wouldn’t have without measuring. Or at the very least rule out moisture as a factor which is just as important.
I have had your experience with PETG on the G10/Garolite plates I prefer with a zero success rate.
I swapped to the Bambu Super Tack and got good results.
Just bought a P1S and couldn’t source BL PETG so bought some Creality CR PETG and it’s working great with the Generic PETG profile. I also subsequently tested with the basic PETG profile and HF profile with the generic coming out best.
The only thing I did was dry the filament before first use.
PETG has three main particularities that need to be accounted for:
It reacts very sensitively to moisture => Always dry it after opening the bag
It loves to stick to the nozzle => Avoid crossing infills and surfaces, go for honeycomb, monotonic, etc
It is slow to realease heat while remaining soft at temp, leading to increased stringing, oozing, warping and curling => enable “wipe on retract”, optionally increase “retraction speed” up to 60mm/s, use “adaptive layer height” and dare to go slow(er). Better one good print than two bad ones in a given time…
As already mentioned, the “melting” of the horns can be avoided by forcing the nozzle away from the print to give them more time to cool. You can either print two (or three) models at the same time and place them reasonably far apart, and/or force a prime tower by enabling a “Smooth” “Timelapse”.
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