Three dimensional printer

A lamination molding apparatus comprising:

• a chamber covering a desired molding region and being filled with an inert gas having a desired concentration;
• a recoater head moving in the chamber to supply a material powder on the molding region to form a material powder layer;
• a material supplying unit to supply the material powder to the recoater head;
• wherein the recoater head comprises:
• a material holding section to hold the material powder;
• and a material discharging opening to discharge the material powder in the material holding section;
• the material supplying unit comprises:
• an intermediate duct to supply the material powder to the material holding section;
• and a main duct to supply the intermediate duct with the material powder;
• the intermediate duct is configured to be capable of discharging the material powder from an intermediate duct outlet capable of vertical movement and having an elongated shape;
• and
• the material supplying unit is controlled to discharge the material powder from the intermediate duct outlet in a condition where the intermediate duct is moved so that the intermediate duct outlet is located at a position lower than the upper end of the material holding section.