I've been changing filament "mid print" for a long time now.
First off, I've noticed that the newest Pronterface does not change the "pause" button to "resume".
I've noticed "printrun-win-Mar2012-slic3r" has been the best version to use for this.
Step 1: Pause
Step 2: Home X button (Clears printed parts)
Step 3: Set extrude mm length to a number the length of your distance from extruder gear to hot end + 10mm.
(I'm using RepRapPro tricolor with Bowden type extruder. The length from my extruder gear to hot end is about 540mm. I set my extrude to 550mm.)
Step 4: Reverse (button is under Extrude button)
Step 5: When filament has cleared extruder gear, place new color against gear, ready to extrude.
Step 6: Click Extrude
(Remember that extra 10mm you added? This is needed to push the first color out. NOTE: if the distance you "extrude" is more then you "reverse", that distance will be reversed again and you will be extruding air.)
Step 7: Resume (Pause button should now be Resume button)
(As print head moves back to last know position, make sure you have tweezers or hemostats or something to keep the glob of plastic from moving to your printed part.)
NOTE: The extra filament extruded to push the previous color out may not be needed if your second layer is tall enough that the color change wouldn't be noticeable. But may be needed to ensure that your new color is ready at the hot end tip and not back a couple millimeters, causing a blank extrude spot.
Let me know if you need a video demonstrating this.
Edited 1 time(s). Last edit at 01/28/2014 06:18PM by KingRahl.
