I am hoping someone can help me with the settings that I must be missing. I have a X1 Carbon (.4m nozzle with high temp plate) and printing with Bambu Labs PETG-CF. I dried the filament for 12hours prior to using, per Bambu instruction.
I am having issues with some stringing on top part of a cutout I have in the print, holes for USB connectors.
I am using the default filament profile with 2 changes:
- Pressure advance changed to .032 (seen this mentioned in another forum)
- AUX Cooling fan at 30% (seen this mentioned in another forum)
- I have tested with different temps on nozzle and bed, but the defaults seem to work best
For the other settings, I am using the Bambu 0.20mm Standard @BBL X1C preset with the below adjustments:
- Sparse infill density 100% and pattern Rectilinear
- Speed:
Could you try to uncheck the Slow down for overhangs option, bridging at 200mm/s as per this thread and see if that improves it?
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… or on the other hand, set bridging speed very low, like 5mm/s or even lower. That was the only way I could get good bridges with PETG, but I have no experience with PETG-CF.
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Hi Organicactus,
I took you advice and unchecked the slow down for overhangs and increased the bridge speed to 22mm/s. While the print did get better, there are still the strings. Getting so close…
I slowed it down to 5mm/s and the strings were much worse
I wonder if this post would help with further finetuning the settings? Some impressive quality PETG-CF parts.
That is one of the first posts I used for reference and used his settings… I’ve made a few more adjustments to match the speed settings in that post, but still not getting the bridge’s without strings…
You will not be able to do this bridge without support unfortunately. Either you rotate your model so that this isn’t bridge anymore or you enable support for it. Whenever I have a bridge like this, I use supports.
The supports did seem to help the strings, but now I have some weird marks at top of the opening on the one side. Not sure what that is from… It’s like i solve one issue and create another.
Earlier, you mentioned bridge speed is 22mm/s. If that is the case, could you try increase that to 200mm/s? It fixed the issue for this guy, worth trying. So you want the settings like this:
Also, rather than reprinting the entire model every time, you could print only the problematic section. Saves you time and filament.
You might need to use supports for that. I’ve found the X1C to do a great job of bridging in general, but PETG is always temperamental. BTW, an engineer friend of mine that does commercial printing says, and you can find some confirmation online, that CF is a bit of a scam. Carbon fiber gets its strength from aligned carbon filaments. The stuff in all the CF plastics are either powder or tiny chunks. They add nothing for strength, possibly a little bit of abrasion resistance.
Sorry but your friend has either been misunderstood or misspoke. CF makes filaments stiffer. See this video for a comparison between CoPA vs various PA+Fibres if you’re interested.
Nevertheless, it is true that conventional 3dp cf filaments use shavings rather than continuous fibers. If you need higher strength than what these offer, there are specialty 3dp machines such as Markforged Mk2 (£20k), which can print continuous cf.
Just to update, I was unable to get the print quality to be good on the bridges. I tried all recommend changes, I also attempted using settings from other forums with no success. I ended up cutting my model in half and printed in two pieces, eliminating the bridges. The quality on that print is very good and will work. Thanks for all the suggestions, unfortunate I could not get it to work out without changing model.
