The process in which plastic granulate is melted in the plasticizing unit and prepared in the required amount for the next injection cycle is called dosing.
During this process, the screw conveys the material forward while it melts through friction and external heating. The screw moves back axially, forming a defined melt cushion. A non-return valve prevents the material from flowing back into the rear section of the screw. The dosing amount is precisely controlled to ensure consistent cavity filling and reproducible part quality. Factors such as temperature, screw speed, and back pressure influence the dosing process and, consequently, the melt quality. Accurate dosing is crucial for the efficiency and quality of the injection molding process.
Injection molding machine: Schematic representation of the dosing process
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