Injection molding method and injection molding machine
View Patent ↗After a first die and a second die are opened, a base film of a film is separated from the first die so as to tilt the surface of the film with respect to a parting face of the first die.
1. An injection molding method comprising the steps of:
causing a long film to travel between a first die and a second die while applying tension to the film including a base film, and positioning the film between the first die and the second die, the film having a surface tilted with respect to a parting face of the first die;
closing the first die and the second die;
forming a molded article with a transfer film by injecting resin into a cavity formed by the first die and the second die that hold a part of the film, the transfer film being transferred from the base film;
opening the first die and the second die; and
separating the base film from the first die so as to tilt the surface of the film with respect to the parting face of the first die,
wherein tension applied to the film gradually increases in multiple steps when the base film is separated from the first die.
2. An injection molding method comprising the steps of:
causing a long film to travel between a first die and a second die while applying tension to the film including a base film, and positioning the film between the first die and the second die, the film having a surface tilted with respect to a parting face of the first die;
closing the first die and the second die;
forming a molded article with a transfer film by injecting resin into a cavity formed by the first die and the second die that hold a part of the film, the transfer film being transferred from the base film;
opening the first die and the second die; and
separating the base film from the first die so as to tilt the surface of the film with respect to the parting face of the first die,
wherein the film slightly moves back and forth widthwise when the base film is separated from the first die, or
tension is applied to the film and the film is released from the tension in an alternating manner when the base film is separated from the first die.
3. An injection molding machine comprising:
a molding unit including a first die and a second die with a long film traveling between the first die and the second die, the film including a base film, the molding unit closing the first die and the second die when the film is positioned between the first die and the second die, forming a molded article with a transfer film by injecting resin into a cavity formed by the first die and the second die that hold a part of the film, and then opening the first die and the second die, the transfer film being transferred from the base film; and
a film feeder including a feeding unit that feeds the film and a winding unit that winds up the film fed from the feeding unit, the film feeder causing the film to travel between the first die and the second die while applying tension to the film having a surface tilted with respect to a parting face of the first die,
wherein after the first die and the second die are opened, the film feeder separates the base film from the first die so as to tilt the surface of the film with respect to the parting face of the first die,
the feeding unit includes a feeding shaft that determines a feed amount of the film, and a feeding pinch roller capable of pressing the film to the feeding shaft such that the film travels in response to a rotation of the feeding shaft, and
the winding unit includes a drawing shaft that determines tension applied to the film, and a drawing pinch roller capable of pressing the film to the drawing shaft such that the film travels in response to a rotation of the drawing shaft.