| 摘要 |
PURPOSE:To attain to enhance dimensional accuracy by making it possible to obtain a uniform wall thickness even if deep drawing is performed, by forming a plastic film under heating at temp. equal to or more than the glass transition point of plastic and applying puching processing to said film at temp. equal to or less than the glass transition point. CONSTITUTION:At first, a palstic film is fed in a state heated to about 50-95 deg.C by a preheater 3 and, subsequently, only a part to be molded is heated to about 110-130 deg.C by a heater 4 for the time equal to that receiving the molding by molds 11, 12. Because said heated part exceeds the glass transition point of the plastic of said film, it becomes extremely limp and can be molded into a desired shape having a uniform thickness by deep drawing. In this case, because the molds 11, 12 are held to 30-50 deg.C by a temp. regulation system, the plastic film reaches a mold to be molded into a desired shape and simultaneously cooled to the glass transition point or less through the contact with the mold to receive punching. By this method, the burr generated at the punched part is reduced and a molded product high in dimensional accuracy is obtained. |
