System for 3d printing

A method comprising:

• providing an additive manufacturing (AM) system comprising a pre-heating assembly and a printing block in a carriage, the pre-heating assembly including a plurality of chambers and the printing block including a plurality of slots for receiving a plurality of printing heads and a pair of reservoirs surrounding each of the plurality of slots;
• heating a plurality of different materials, wherein each of the plurality of different materials is heated in a separate chamber of the pre-heating assembly;
• simultaneously delivering contents of all the plurality of different materials from the pre-heating assembly to a plurality of printing heads, wherein the number of chambers in the pre-heating assembly exceeds the number of printing heads, wherein each of the plurality of different materials from the pre-heating assembly is directed to the printing heads via the pairs of reservoirs, wherein each reservoir of the pair of reservoirs is in fluid communication one of the plurality of printing heads;
• and
• dispensing all the plurality of different materials with the plurality of printing heads by three dimensional inkjet printing, wherein each of the plurality of printing heads is configured to receive material from the pair of reservoirs and to dispense the material from each reservoir with a separate nozzle array.