Injection molding machine with auxiliary packing means

Claim 1

An injection molding machine for molding a plastic material, comprising: barrel means for melting the plastic material and for extruding a melt of the plastic material, said barrel means having two ends; a heated cylinder within said barrel means for containing the plastic material, said cylinder having a screwed ram rotationally disposed therein; a feeder for dispensing the plastic material into the heated cylinder, said feeder mounted on one end of said barrel means; an outlet nozzle for extruding the plastic melt from said heated cylinder, said outlet nozzle located at the other end of said barrel means; packing means for accepting an amount of said extruded plastic melt from said outlet nozzle, said packing means having a heated tubular housing; a sliding member disposed in said tubular housing for sliding displacement, said sliding member and said tubular housing forming a packing chamber for accepting said plastic melt; a mold cavity coupled to said packing means; drive means associated with said packing means for displacing said sliding member to reduce the volume of said packing chamber for forcing the plastic melt contained in said packing chamber into said molding cavity; control means for controlling the rotation rate of said screwed ram, the plastic material dispensing rate of said feeder, and the temperature of said heated cylinder; a plurality of pressure sensors disposed along the length of said heated cylinder for sensing pressures along the interior length of the heated cylinder, said pressure sensors being electrically coupled to said control means to supply said control means with signals respecting the pressure profile along the interior length of said heated cylinder; a plurality of temperature sensors disposed along the length of the interior of the heated cylinder for sensing temperatures along the interior length of the heated cylinder, said temperature sensors being electrically coupled to said control means to supply said control means with signals respecting the temperature profile along the interior length of said cylinder; and said control means being such as to regulate the rotation rate of said screwed ram, the plastic material feed rate of said feeder and the temperature of said heated cylinder in response to said sensed pressure and temperature profiles.