What do you do when changing filament colors?

For the time I have been using my printer I have been exclusively using red hatchbox pla. I ordered some blue pla and was wanting to know if there is any more to changing filament than pulling the old out of the extruder and putting the new in.

Generally, you get a little cleaner change if you take the hot end up to maybe 20C below your normal extrusion temperature (say, 180 for PLA) and gently hand-extrude a little filament, then lower the temperature another 20C before you retract it. You'll still have to extrude some after the change before you stop getting old filament with the new.

Would it be worth putting a bit of 'natural' filament through between the two colours?

I don't really see any value-added. The filaments are compatible. They can even be mixed at nearly-infinitely-variable ratios in something like a Cyclops.

I run an E3DV6-lite, and going from bright red to white, I am clear after 70mm or extrusion or so, although I'll usually squirt more like 100 to be safe.

I have two macros in Pronterface - unload, which sets 180 degrees and waits formit (M109), and the reverses 450mm or so (enough to clear the extruder) and then wets 100 degrees awaiting the load. Load fires in an M302 (extrude cold), and runs in 430mm (enough to stop just short of the hot end) and then I manually set temp for what I am running, and bump 10mm extrusions manually until the color is clean.

- Tim

Edited 1 time(s). Last edit at 07/29/2015 12:35AM by tadawson.

450 and 430mm seem an awfully long distance... presumably you're running a Bowden setup?

Yup - bowden on a kossel. The point was the use of macros to simplify the process, not the specific lengths . . . they might even be higher, I'm not at that system to verify at the moment . . .

- Tim

Edited 1 time(s). Last edit at 07/29/2015 12:52AM by tadawson.

To change my filament, I heat the hotend at 80°C and then remove the PLA. Doing so, almost all the filament is removed from the hotend in one block. When I print a new piece, the printer make just one skirt around the piece, it is sufficient to purge the rest of old filament.
For ABS, I do the same at 120°, but it will stay more residues than with PLA.

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Prusa i3 - e3d v5 - Gnu/Linux - Pronterface - Slic3r - Octoprint - Rpi - French

I just cut the old filament and push the new one in right after it, while extruding slowly. Works perfect for 2 years now...