If the was an option for a prime tower for each of the colours or materials in a model this would be useful as then any prime tower blocks could be ground up and used to make new filament as opposed to going to waste.
At the moment because the colours / materials are all in one block - this is not possible.
Personally I like to recycle as much as possible and would prefer to be able to create new filament in a single colour from these blocks as opposed to some monstrosity of a colour created from all of them - or useless material because it has mixed materials in one block.
(The head would have to lower, and could collide with existing stuff on the build plate) . BBL can’t even do ‘print by object’ properly, no way could they cope with what you ask. Anyway, mix it with black, it’ll do.
With the print I am currently doing the head lowers and raises anyway at various points as it does over the tower, all I am talking about is having two separate towers away from the object being printed one for each colour is it really that hard?
Its basically.
Remember current head position.
Purge
Unload filament
Load New filament
Run in of filament to appropriate coloured block to get it flowing.
Return to remembered head position
Resume print with new filament.
Im not an expert on g-code but surely thats do able.
I think by some of the responses and more importantly, lack of responses, this is a pretty tall ask for a very small benefit.
If you want to make your case, I think you’ve first have to convince the audience that the notion of recycling filament is one that is real and present in their daily lives. So far, the only methods presented on YouTube have been half-baked demonstrations with a financial investment in equipment and time that proved not to be worth it. In fact, the one’s that come to mind can do this job already and the only sacrifice is that one would get a mono-color output.
Let’s be honest, how many uses cases are there for this?
It is doable, but not easily for every general case. Waste can be avoided/reduced by reducing the number of colours or printing a number of the same objects on the plate. gcode is not that complicated, at least the standard movement ones, and you could experiment by printing, say a two colour cube, and putting the purge where you want (the layer changes are commented, as well as loads of other stuff in the gcode in most slicers, and it can be edited with any text editor.) However, like connecting short lengths of filament with a filament splicer, it is not worth the effort, or time or expense for most people. If it is a recycling/environment thing, then most of the stuff that folk print ends up as landfill or incinerated, but it could be an interesting experiment.