I now own the Prusa3D MMU2. The benefits, costs, and experience others have had is well documented. I am interested in rebuilding my large, home-designed delta machine to be multi-material, and don't want to overlook strategies I haven't considered.
My original implementation used an E3D Kraken as the hot-end, and handled the inevitable delta tilt by adding two additional degrees of freedom to the head to lower the selected nozzle to the bed. I've been through three generations of mechanisms, and I think the third will work.
But, I feel that I am not seeing obvious and better alternatives.
So, the question: Through what methods and mechanisms can a multi-material (different polymers, different temperatures) FDM printer operate, and are there available designs or examples of best practices for those methods?