PURPOSE: To inexpensively produce a highly accurate plastic molded product by obtaining transfer accuracy even with respect to a matrix whose wt. is less than a predetermined wt. by generating pressure other than the pressure of a resin in the cavity of a mold in the molding of the plastic molded product to increase the wt. tolerance width of the matrix.
CONSTITUTION: An injection molding process injecting a thermoplastic resin into an injection mold to mold a matrix 11 having an almost final shape and an ageing process inserting the matrix 11 in the cavity of an ageing mold having a molding surface almost same to that of the injection mold and having a transfer surface and heating the matrix to the glass transition temp. or higher to generate predetermined internal pressure Pc in the cavity to transfer the transfer surface and gradually cooling the matrix to thermal deformation temp. or lower are provided. Before the ageing process, a space 12 is formed in the matrix 11 and a mixture 13 generating gas 14 when heated to the glass transition temp. of the matrix or higher is inserted in the space 12 to generate the gas 14 in the matrix 11.
OSEKO HISAAKI
HIRANO AKIO
WATABE JUN
ITO HIDENORI
OTANI WATARU
KANEMATSU TOSHIHIRO
