![](https://lemmy.redkrieg.com/pictrs/image/da4d3225-dd11-4d67-92ed-3f9b5bea3638.jpeg)
![](https://linux.community/api/v3/image_proxy?url=https%3A%2F%2Flemmy.world%2Fpictrs%2Fimage%2Fe4083c7c-83c3-4258-8370-708e95e309b3.png)
Before you go through a bunch of calibration, I’d see if it happens with a different filament. Those black particles there are likely something with a higher melting point than the surrounding PLA, otherwise they’d “smear” during printing. I’m betting you’re hitting some intermittent clogs. See if the problem happens with a single color filament.
I’m guessing this judge considers the telephone to be an example of negligent design as well. After all, the phone company doesn’t record every phone call I make and disconnect me if I mention an illegal drug.