Patent ID: 8657595

Claim:
A device for the transformation, by heating through conduction of thermoplastic matrix composite materials or thermosetting materials, said device comprising: a. two mold casings that are mobile relative to each other, made out of an electrically conductive material having first electrical resistivity, each casing comprising external surfaces and a molding face comprising dies complementary in shape and designed to be in contact with the material to be transformed in order to heat the material by conduction, and b. induction means enveloping the casing of the mold for generating an oscillating magnetic field with a frequency F ranging from 25 KHz to 100 KHz, c. one or more external surfaces of at least one of the two mold casings situated to face the induction means, being coated with a shielding layer made of a non-magnetic material having a second electrical resistivity which is lower than the first electrical resistivity to permit currents induced from the magnetic field to flow around the external surfaces of each mold casing while preventing the magnetic field from penetrating into the external surfaces of the mold casings facing the induction means, said shielding layer extending over a part of the molding face outside of the die surface and being electrically connected to the die surface of the molding face to form an electrical pathway between the shielding layer and the die surface of the molding face, said shielding layer having a thickness greater than a penetration depth of the magnetic field and at least equal to 50*(p/F) 1/2 with p being the resistivity of the non-magnetic material and the thickness being less than one millimeter, so that the magnetic field is prevented from reaching the mold casing and heating it other than the die surface, and d. the mold casings being electrically insulated from each other during the molding phase so that the molding faces of the two mold casings are separated by an air gap, wherein the magnetic field induces the currents that flow continuously through the electrical pathway from the shielding layer to the die surface of each mold casing to concentrate the heat generated through a Joule effect to the die surface of each molding casing.