VACUUM EXTRUSION FORMING MACHINE

PURPOSE:To effect the deaeration of material sufficiently, eliminate generation of bubbles in a formed piece and improve the strength of the formed piece by a method wherein evacuation is effected through an air discharging port provided a cap or immediately before the cap. CONSTITUTION:An air discharging port 18 is provided immediately before a cap 5 at the terminal section of a barrel 4 and evacuation of the inside of barrel is effected through the discharge port 18. The air discharging port may be provided on the cap itself. In order not to enter a material into the aid discharge port 18, a spring plate 19, having an area larger than the area of the air discharging port, is provided at the entrance of the air discharging pot 18 and when the material does not arrive at the position of the spring plate, the spring plate is separated from the air discharging port and evacuation may be effected through the air discharging port. When the material has passed the position of the spring plate 19, the spring plate is pushed by he material and the air discharging port may be blockaded by the spring plate.