[pen2l]

> It would be interesting to print a cancer tumor with one material the and the surrounding tissue with another. Some data here: http://www.cancerimagingarchive.net

Wow, that's like the first cool reason I have stumbled upon for a dual-extruder printer. :) (a lot of people think they need a printer with dual-extruders -- they don't, and actually the biggest reason they don't need it is 3d printing suddenly gets twice as difficult when you're doing it with dual-extruders)

[kefka]

> 3d printing suddenly gets twice as difficult when you're doing it with dual-extruders

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.

[iamflimflam1]

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.