An extruder assembly for a three-dimensional printer comprising: an extruder for extruding a filament onto a printing platform; and a cutting device for cutting the filament, wherein the cutting device is fixedly connected to the extruder; a housing for housing the extruder and at least a portion of the cutting device ; and a supply motor for supplying the filament to the extruder, wherein the supply motor is positioned between the cutting device and the extruder along a path of filament supply; the cutting device comprising: a first portion attached to the extruder assembly of the 3D printer; and a second portion , wherein each of the first portion and the second portion includes a respective cutting edge (117; 118) for cutting the filament; wherein the first portion is fixed relating to the extruder assembly and the second portion is movable relative to the extruder assembly and the first portion ; wherein the cutting edge of the first portion and the cutting edge of the second portion are situated above a filament intake region of the extruder assembly, the filament intake region being located inside the housing immediately above the supply motor .; wherein the cutting edge of the second portion and the cutting edge of the first portion are housed inside the housing ; wherein at least a portion of the second portion is positioned outside the housing ; wherein the second portion is hingedly connected to the first portion , a cutting force is applicable to the second portion , and the second portion is configured such that, when the cutting force is applied thereto, the second portion transfers the cutting force to the cutting edge of the second portion . an extruder for extruding a filament onto a printing platform; and a cutting device for cutting the filament, wherein the cutting device is fixedly connected to the extruder; a housing for housing the extruder and at least a portion of the cutting device ; and a supply motor for supplying the filament to the extruder, wherein the supply motor is positioned between the cutting device and the extruder along a path of filament supply; the cutting device comprising: a first portion attached to the extruder assembly of the 3D printer; and a second portion , wherein each of the first portion and the second portion includes a respective cutting edge (117; 118) for cutting the filament; a first portion attached to the extruder assembly of the 3D printer; and a second portion , wherein each of the first portion and the second portion includes a respective cutting edge (117; 118) for cutting the filament; wherein the first portion is fixed relating to the extruder assembly and the second portion is movable relative to the extruder assembly and the first portion ; wherein the cutting edge of the first portion and the cutting edge of the second portion are situated above a filament intake region of the extruder assembly, the filament intake region being located inside the housing immediately above the supply motor .; wherein the cutting edge of the second portion and the cutting edge of the first portion are housed inside the housing ; wherein at least a portion of the second portion is positioned outside the housing ; wherein the second portion is hingedly connected to the first portion , a cutting force is applicable to the second portion , and the second portion is configured such that, when the cutting force is applied thereto, the second portion transfers the cutting force to the cutting edge of the second portion . <EOS>