Abstract: A device for heating a press tool (4), which is mounted in a press (3) for manufacturing products wholly or partially of plastic or composite, consists of a core (1) of electric sheet steel, a coil arrangement (9, 10, 11) placed around the core (1), and a voltage source (12). The voltage source (12) is connected to the coil arrangement (9, 10, 11) for generating a magnetic field in and around the core (1). The core (1) has two poles (8a, 8b) which, between themselves, receive the press tool (4) and are displaceable in relation to one another for applying a press force to the press tool (4) and conduct the generated magnetic field into the press tool (4). A press (3) comprises such a heating device and is used in a manufacturing method where the press tool (4) is heated by the magnetic field supplied thereto.

Abstract: A device for heating a workpiece includes a coil arrangement connected to a voltage source for generating a magnetic field. The coil arrangement is positioned around a core of electric steel sheeting having two poles spaced apart to form an air gap for accommodating a central portion of a workpiece. One of the poles is movable wherein the poles engage the workpiece which bridges the air gap or engage each other by extending through the center of an annular workpiece. The coil arrangement includes first and second coils, each positioned about one of the poles, generating a magnetic field inside and outside the core. The magnetic field concentrated in the core heats the central portion of the workpiece while outer magnetic field heats peripheral portions of the workpiece to achieve a rapid and uniform heating of the workpiece. At least one of the coils can be moved with respect to the associated pole to control the heating of the workpiece.