Abstract: A system for optimizing the multi-extruder deposition process in a 3D printer including multiple extruders requires each extruder to have a body including an outer thermal insulation shell; the shell allowing the inlet/outlet of a fluid for the active and controlled refrigeration of the extruder. A method for optimizing the multi-extruder deposition process in a 3D printer with multiple extruders involves managing the temperature of each extruder using active refrigeration sized so as to have a sudden control of the cooling ramp and to manage the viscosity of the material in the event of extruder change. For the entire duration of the printing with another extruder, the unused extruder nozzle remains in a limited range around the extrusion temperature, thus eliminating downtime, while the solidified filament from the sudden forced cooling is pulled back into a low temperature nozzle area where it does not degrade during non-use.