Patent ID: 7906048

Claim:
A machine for injection molding comprising: a barrel having an interior and having a longitudinal axis; a screw auger positioned within the barrel interior, wherein the screw auger is substantially concentric with the barrel and is operable to rotate and transmit a material along the length of the barrel, wherein the screw auger includes a bore also substantially aligned with the longitudinal axis; a plurality of heating elements, wherein the plurality of heating elements is in thermal communication with said barrel; a plunger, wherein the plunger is substantially aligned for movement along the longitudinal axis and with the bore, wherein the plunger is substantially coaxial with said screw auger, and wherein the plunger is capable of translating along an axis of the plunger relative to said screw auger; an injection chamber; a channel, wherein the channel provides fluid communication between the injection chamber and the barrel; an injection tube wherein the injection tube is in fluid communication with the injection chamber, and wherein the injection tube is located adjacent the plunger; and a plurality of sensors, wherein the plurality of sensors includes a plurality of pressure sensors and temperature sensors wherein at least one of the plurality of sensors is in communication with one of the barrel, the injection chamber, and the injection tube, wherein the plunger in a first position impedes fluid communication between the barrel and the injection chamber, wherein the plunger in a second position does not impede fluid communication between the barrel and the injection chamber; wherein rotation of the screw auger is dependent of a first pressure reading obtained from a first pressure sensor and a second reading of a second pressure sensor, wherein the first reading is indicative of a force applied to the screw auger in a direction that is substantially along the longitudinal axis, and wherein the second reading is indicative of a pressure of the material when heated to at least a flowable state; said screw auger configured within said barrel in a manner that substantially prevents the plastic being conveyed therein from being sheared, with tolerances between said screw and said barrel being sufficient such that gaps between an inside diameter of said barrel and an outside diameter of said screw are small enough so that plastic pellets cannot be sheared therebetween; and wherein a barrier is formed by the compaction of pellets within said barrel as said pellets travel toward a melting zone, said barrier preventing melting plastic from flowing backward in said machine, said machine being devoid of a valve that prevents substantial flowback of melted plastic.