Induction heating device for molding parts with small dimensions

A mold, configured for molding a part comprised in a diameter smaller than 10 mm, the mold comprising a casing adapted for being assembled on a press platen, the casing comprising a housing configured to receiving an insert;

• the insert being configured to be integrated into the casing and comprising a housing for a die comprising a molding portion bearing a molding surface with a molding surface perimeter outer diameter adapted for molding the part;
• a heating device for heating the die;
• wherein the heating device comprises:
• a rod comprising a first portion, a second cylindrical portion with a portion outer diameter, made of a material of high magnetic permeability and a third portion made of a steel susceptible to induction heating and making the molding portion integral with the second cylindrical portion, the rod being mounted in the insert, the molding surface being substantially centered with respect to the second cylindrical portion;
• and
• a coil made of copper comprising an annular portion and stems for a connection to a high-frequency current generator, both a cross section of the stems and across section of the annular portion being less than or equal to 10 mm2, an inner diameter of the annular portion being greater than the portion outer diameter, an insulating ring made of an electrically insulating material transparent with respect to a magnetic field and resistant to a temperature generated in the coil being comprised between the annular portion and the second cylindrical portion, so that when the coil is supplied in electric current by the high-frequency current generator, it generates an induced current in the second cylindrical portion, heating the second cylindrical portion by induction, the second cylindrical portion transmitting a heat by conduction through the second cylindrical portion and the third portion to the molding portion and the molding surface;
• wherein the portion outer diameter is greater than the molding surface perimeter outer diameter and greater than a diameter of the molding portion over a length of the third portion.