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.