Rotoforge is a free and open source hardware/software 3d printer for printing metal, plastic and ceramic heterogeneously on the home desktop safely and affordably with performance similar to FDM. It uses friction welding to locally heat, form and bond metal/plastic/ceramic wire/rod/sheet/powder into 3D objects. 

Contact: https://rotoforge.com/

github: https://github.com/Sindry-Manufacturing/rotoforge