completely removed from the blow molding cavity 7 the movement of the extruder head 4 is stopped and vice versa as is shown in fig7 the extruder head 4 with the extruded tube piece t and the finish blown bottle b which is still connected to it is moved down in the direction of the blow molding tool 6 the blowing mandrel 11 which is mounted on the blowing mandrel support 16 is likewise lowered fig6 and 7 clearly show that the extruded tube t even with the blow molding tool 6 opened is held in a position which is aligned in an axially defined manner because the tube is still connected to the finish blown container b the tube on the one hand is fixed by the extrusion nozzle 6 and on the other via the blowing mandrel 11 in this way swinging of the tube t is reliably prevented the rate of lowering of the extrusion head 4 and of the blowing mandrel 11 takes place advantageously synchronously and corresponds at least to the extrusion speed of the tube t by a definable difference of lowering speeds the continuously extruded tube t can be stretched to the desired extent the axially aligned arrangement of the extruder head 4 of the blow molding tool 6 and of the blowing mandrel 6 also allows relatively simple control of the axial components of motion advantageously the exit speed of the plastic tube t the motion of the blowing mandrel 11 and the adjustment motion.