A Multiple Extruder on a rotating turret idea for FFF / FDM 3D printers *Updated*

I've been puzzled for quite a while over the issue of the design of multiple extruders on FDM 3D printers. Most of the current design dictates an XY offset, which I feel cannibalizes on the XY build space of the printer. Not only that, it requires multiple feed motors, one for each nozzle, and that does add significant inertia to the moving head, generating much unwanted vibrations. Another common solution was to use bowden extruders, which suffers from poor retraction performance.
So I started to think of a solution that tackles all my peeves at one go.

I ended up with a design that can comfortably take up to 5 nozzles in a relatively small area, and only requires 2 motors - one to drive the feed gears, and another to switch the nozzles around a rotating turret. Each nozzle/hotend will have its own feed gears which will mesh with feed motor when it's in the printing state.

concept for multiple extruder design
concept for multiple extruder design

So far it's still a concept and a drawing. Altho I'm a mechanical engineer, I'm not in a good position to actually implement it due to my work commitments and lack of firmware programming skills. So I will leave this idea with the wonderful and innovative folks of the 3D printing world to try it for yourselves if you decide it's worth a go.

Cheers~~

-James

From the (lack of) response in the reprap forum, I'd guess that my drawing sucked. lol

So I tried a sketchup model to see if I can get the idea across more easily.

extruder1

extruder2

extruder3

extruder4