Injection molding method and injection molding apparatus

摘要

The present invention provides an injection molding method which intends to lower a mold clamping force in view of both of a projected area of a molded article and an injection pressure, and contributes to an energy saving and a reduction in a cost of equipment and a manufacturing cost. In a cavity ( 13 ) formed in a metal mold ( 5 ) for an injection molding, there are arranged a first gate ( 21 ) injecting a first molten resin ( 101 ) anteceding in one end side (a charging start side) in a longitudinal direction, and a second gate ( 22 ) injecting a second molten resin ( 102 ) following in another end side (a charging finish side). The second molten resin ( 102 ) is newly injected from the second gate ( 22 ) before a fluid head portion of the first molten resin ( 101 ) injected from the first gate ( 21 ) reaches a position of the second gate ( 22 ). Further, the first molten resin ( 101 ) becomes in an approximately cooled and solidified state by the time when the second molten resin ( 102 ) reaches a terminal end in the charging finish side within the cavity ( 13 ).