Oh look, as the esteamed @Whosa_whatsis observes, the bot objects machine is an Ultimaker gantry with (imo) a not very elegant mixing nozzle.
I wonder how it will hold up against the prototype colour mixer @Sanjay_Mortimer is working on.
I just can’t really see the use case/cost-complexity ratio being a viable one for something that prints different colours for different layers.
Originally shared by Whosa whatsis
What Botobjects is doing looks less impressive every time we get more information. Now we can see that they’re using open source extruders (http://www.reprappro.com/documentation/RepRapPro_mini_extruder_drive_printing) on a closed-source machine (a license violation) with a cartesian bot ripped straight from Ultimaker.
http://techcrunch.com/2014/02/05/an-exclusive-look-at-the-botobjects-prodesk3d-color-3d-printer
As far as @Joshua_Rowley and I see things, being able to do a colour per layer is a waste of time. Our work focusses very strongly on sharp and responsive changes in colour that should allow you to do the sort “full colour” printing that people actually expect.
@Sanjay_Mortimer My thought experiments wrt to true full colour FDM had caused me to discount frequent colour variations in the xy plane. I’d considered a cylinder with a chess board texture mapped to it’s surface so you’d need to quickly switch from white to black repeatedly for each layer, it ‘felt’ like it wasn’t practical because you need to consistently hit a specific cmy+alpha value in an exact position relative to the previous layer for every change in colour, this would either mean a highly controlled and precise instant change in colour without interrupting the movement of the nozzle around the perimeter, or moving to an infill region or prime pillar to purge the previous colour before resuming. The first option seems impossible if my understanding of how you might mix colours is correct and the second would likely produce undesirable surface artefacts.
Both would require significant slicer augmentations and probably come changes to the input file (amf or stl).
I know you have a build it and they will come attitude to this stuff but it seems like a really big endeavour for a limited use case.