An extruder apparatus for the extrusion of a strand of building material for 3D printing of a structural part includes an extruder nozzle and at least one inner element. The extruder nozzle has a discharge opening for the discharge of the strand of building material out of the extruder apparatus. The at least one inner element is designed for arrangement within the extruder nozzle for purposes of defining an inner edge of a flow cross section of building material within the extruder nozzle in order to specify an inner edge of a strand cross section of the discharged strand of building material.

A method for forming a plugged honeycomb article includes feeding a ceramic precursor material through an extrusion die, the extrusion die having a plurality of pins, a plurality of cavities bounded by adjacent pins, and alternating end-faces of the plurality of pins include extensions extending from an outlet of the extrusion die in an extrusion direction. The method further includes extruding the ceramic precursor material through the extrusion die to form a web structure comprising a plurality of cell walls and channels bounded by adjacent cell walls, supporting the web structure that has been extruded through the extrusion die, and providing movement between the extrusion die and the web structure in at least one direction substantially orthogonal to the extrusion direction while the extensions are positioned in at least a portion of the channels.

Method and apparatus for casting prefabricated concrete products with a substantially horizontal slipform casting process, where the concrete mass is fed in at least one feeding stage to a slipform casting mold compacting and defining the product to be cast, wherein at least one part is embedded in the concrete mass after the at least one concrete mass feeding stage and before the final compaction of the upper surface of the product to be cast.

A method for forming a plugged honeycomb article includes feeding a ceramic precursor material through an extrusion die, the extrusion die having a plurality of pins, a plurality of cavities bounded by adjacent pins, and alternating end-faces of the plurality of pins include extensions extending from an outlet of the extrusion die in an extrusion direction. The method further includes extruding the ceramic precursor material through the extrusion die to form a web structure comprising a plurality of cell walls and channels bounded by adjacent cell walls, supporting the web structure that has been extruded through the extrusion die, and providing movement between the extrusion die and the web structure in at least one direction substantially orthogonal to the extrusion direction while the extensions are positioned in at least a portion of the channels.

Method and apparatus for casting prefabricated concrete products with a substantially horizontal slipform casting process, where the concrete mass is fed in at least one feeding stage to a slipform casting mold compacting and defining the product to be cast, wherein at least one part is embedded in the concrete mass after the at least one concrete mass feeding stage and before the final compaction of the upper surface of the product to be cast.