Abstract: An extruder head assembly includes an extruder head having an extrusion line which is inserted in a cylindrical seat formed in said extruder head; the extruder head includes a locking means configured to hold the extrusion line in a working position; the locking means being actuated to release the extrusion line and allow the extraction thereof from the seat. The locking means include dowels that are radially movable between a locking position and a release position, the release position allowing the extraction of the extrusion line.