INJECTION MOLDING METHOD

PURPOSE:To increase reinforcing effect by fiber and upgrade the quality of a molded product by using a device in which vibrators for vibrating resin injected into a mold cavity are provided on the mold side and carrying out injection while vibrating the resin by the action of said vibrators. CONSTITUTION:A plurality of vibrators 19 provided in an opening of a movable mold 7 generate supersonic wave vibration and vibrate the same in the axial direction by applying high frequency voltage to vibrators to vibrate resin having fluidity in a cavity 9 through an insert die 8. Clamping is stopped in the state of lightly opening molds 3 and 7 and resin 18 is injected into a cavity 9. While said resin 18 has still fluidity, the vibrators 19 are vibrated to vibrate the insert die 8 in the axial direction and vibrate the resin 18, and glass fiber, for instance, as an additional material injected in the state of being curved into the cavity 9 is stretched straight by varying the fluidizing state of the resin in the mold. After that, clamping is carried out to compress, density and solidify the resin 18 in the cavity 9.