Injection method of preplasticization injection molding machine

A method of using a preplasticization injection molding machine having a plasticization chamber for plasticizing a synthetic resin material, an injection chamber for injecting the synthetic resin material into a mold die cavity, a plunger mounted in said injection chamber for reciprocal movement therein, and a connection passage connecting said plasticization chamber and injection chamber, said method comprising:

• measuring the synthetic resin material plasticized in said plasticization chamber as it is fed to said injection chamber through said connection passage, said measuring step terminating at a measurement detection position;
• blocking said connection passage;
• detecting a blocking position of said plunger after said step of blocking;
• preliminarily compressing the synthetic resin material in said injection chamber to a predetermined pressure;
• detecting a preliminary compression position of said plunger after preliminarily compressing the synthetic resin material;
• controlling the filling of the mold die cavities with said synthetic resin material based on said preliminary compression position;
• correcting the measurement detection position for the next measuring step based on a movement of said plunger from said measurement detection position to said blocking position.