METHODS OF SELECTING TERMOPLASTIC MATERIALS FOR USE WITH PLASTIC ARTICLE FORMI NG APPARATUSES THAT CONTROL MELT FLOW

摘要

A method of selecting thermoplastic materials for use with an injection molding apparatus that adjusts viscosity of a thermoplastic material based on an interpreted viscosity is provided. The method includes determining a target MFI for an identified plastic article based on performance properties. A thermoplastic material supply chain is analyzed and a first thermoplastic material having a first starting MFI and a first MFI range is identified and a second thermoplastic material having a second starting MFI and a second MFI range that is greater than the first MFI range is identified and is priced less than the first thermoplastic material. The second thermoplastic material is purchased. The second thermoplastic material is tested by providing the second thermoplastic material to the injection molding apparatus for multiple shot molding cycles with the second thermoplastic material in a molten state. The step of testing includes monitoring melt pressure of the molten second thermoplastic material using a sensor and providing a signal to a controller indicative of melt pressure. The controller controls introduction of an additive to the second thermoplastic material thereby changing a viscosity of the molten second thermoplastic material based on the signal. A molded article is formed by reducing a mold temperature of the second thermoplastic material within the at least one mold cavity.

主权项

1. A method of selecting thermoplastic materials for use with an injection molding apparatus that adjusts viscosity of a thermoplastic material based on an interpreted viscosity, the method comprising:
determining a target MFI for an identified plastic article based on performance properties; analyzing a thermoplastic material supply chain and identifying a first thermoplastic material having a first starting MFI and a first MFI range and identifying a second thermoplastic material having a second starting MFI and a second MFI range that is greater than the first MFI range and being priced less than the first thermoplastic material; purchasing the second thermoplastic material;
testing the second thermoplastic material by providing the second thermoplastic material to the injection molding apparatus for multiple shot molding cycles with the second thermoplastic material in a molten state, wherein the step of testing includes monitoring melt pressure of the molten second thermoplastic material using a sensor and providing a signal to a controller indicative of melt pressure, the controller controlling introduction of an additive to the second thermoplastic material thereby changing a viscosity of the molten second thermoplastic material based on the signal; and forming a molded article by reducing a mold temperature of the second thermoplastic material within the at least one mold cavity.