Moulding assembly (100) with an inlet (117) for receiving raw material to be ejected, a barrel (112) for gathering and processing the raw material received through the inlet (117), a screw (110) for engaging the raw material in the barrel, a first drive unit (170) configured for rotating the screw (110) in order to grind the raw material into liquid form, where the moulding assembly further comprises a second drive unit (120) configured to displace the screw (110) in a direction essentially perpendicular to the rotation direction in and out of the barrel (112) depending on the pressure in the barrel (112).