SCREW AND INJECTION DEVICE

摘要

A molding material can be melted in a short time and the extended distance of a groove (67) is reduced. A screw (20) has a flight forming section (45) rotatably placed in a cylinder member and having a body portion (45a) and a flight (53), and also has a pressure member (54) placed in front of the flight forming section (45). The flight (53) is constructed from flight portions (53a, 53b) in a predetermined segment of the flight forming section (45). In a groove depth setting section, if the diameter of the molding material is ð1 and the depth of the groove (67) formed along the flight (53) is Ä1, the ratio (³1) of the groove depth Ä1 to the diameter ð1 satisfies the relationship of 1‰¤³1‰¤2.5. Consequently, the non-uniformity of flow of the molding material is prevented from occurring in the flight forming section (45).