Best ways to avoid oozing left behind by darker filament?
What are the best ways to avoid this? I assume it happens when I change from a dark filament to a lighter colored one and there is material left behind somewhere? I always let the new color feed/purge multiple times to make sure the old color is not bleeding/blending but then the print finishes and I see this either on the top layers or on the underside.
RE: Best ways to avoid oozing left behind by darker filament?
I use a brass brush before and after each print to quickly remove bits of filament stuck to the nozzle and block, being careful of the wires for the thermistor and heater cartridge. you should recognize that when you do this it will leave tiny bits of debris on the bed and they should be removed before starting next print.
The debris is burnt black or brown from being on the heater block.
The Filament Whisperer
RE: Best ways to avoid oozing left behind by darker filament?
I also (try to remember to) brush off the nozzle area with a brass brush when starting a print. I also try to remember to visually inspect the nozzle area for any 'boogers' or anything that does not look right.
I'll also, when changing filaments, be sure that there's no contamination from the old filament to the new. I do this more aggressively when changing from a darker to a lighter filament, or one species of filament to another, and particularly when changing from a metallic to a so-called transparent filament. I'll usually answer 'no' to the 'Is the filament the correct color?' question, do it twice from a dark to a light or one type to another, and several iterations when changing from a metallic.
RE: Best ways to avoid oozing left behind by darker filament?
Could leaking from above the nozzle, check if there are now leaks, normally it should be more visible.
If I change filament, especially from abs to pla, I feed the pla in with the higher temp, then purge the nozzle a few times, then lower temperature to pla and purge again.
If you cannot solved this, with cleaning nozzle with brass brush and purging, you could try a cold pull, see on prusa website how to do a cold pull.