In this case, you extrude motor 1 and print. Then to switch, you retract until you're before the Y, and extrude with filament 2. Use a wipe-tower to get a consistent flow, and you have 2 colors (of the same material) with 1 hotend.
It is very easy to jam one of the colours, you have to be very careful about retraction distances because if you retract to far the other colour can leak into the cold end part and solidify and then you only have one colour working.
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Not really... If you use something like this http://www.thingiverse.com/thing:1680034
In this case, you extrude motor 1 and print. Then to switch, you retract until you're before the Y, and extrude with filament 2. Use a wipe-tower to get a consistent flow, and you have 2 colors (of the same material) with 1 hotend.
My experience would be that it is a lot more difficult.
I've got one of these (the cyclops) and when it works it works well (although even with a wipe tower you get some colour bleed).
https://printedsolid.com/products/e3d-dual-extrusion-chimera...
It is very easy to jam one of the colours, you have to be very careful about retraction distances because if you retract to far the other colour can leak into the cold end part and solidify and then you only have one colour working.