PURPOSE: To mold a piece for testing physical properties efficiently by a method wherein a material to be tested and a reference material are put alternately in a number of hoppers on a material supplying rotary table and the materials are injected sequentially, whereby cleansing of an injection molding machine in every process is unnecessitated.
CONSTITUTION: The material to be tested A, B and C and the reference material X are put alternately in a number of hoppers 2 on the material supplying rotary table 1, these materials are supplied to the injection molding machine 8 sequentially, and the piece for testing physical properties is molded through injection and held in a molded article holding vessel 6 on a molded article holding rotary table 5. Since the reference material X is injected prior to the injection of the material B to be tested, the injection molding machine 8 is cleansed by the reference material X and the material B is not mixed with the material A to be tested in the previous process, whereby the piece for testing physical properties with high purity is molded through injection. The physical properties of this piece is measured and the molecular weight thereof is determined, whereby the conditions of injection molding for the full- production are fixed.
Next Patent: DRIVING DEVICE FOR LOCK PIN IN INJECTION MOLDING MACHINE