General Electric Company

Philip C Sturman, Jr

Robert A Gray

Induction heating is utilized to heat polymer matrix composites containing electrically conductive fibers. This is accomplished with an apparatus having a mold with first and second cores positioned to receive a workpiece therebetween and first and second induction coils mounted to the first and second cores, respectively. Each induction coil is encapsulated in a layer of non-electrically conductive material which is attached to a surface of the respective core. A thermal insulation layer is attached to each layer of material, and a skin layer is attached to each thermal insulation layer. Alternatively, the induction coils can be embedded in the corresponding mold core. In another alternative, a single helical induction coil can be disposed around the two mold cores.

Induction heating of polymer matrix composites in a mold press

Induction heating is utilized to heat polymer matrix composites containing electrically conductive fibers. This is accomplished with an apparatus having a mandrel for supporting a composite workpiece and a helical induction coil disposed around the mandrel. The mandrel, workpiece and induction coil are disposed in an autoclave. The mandrel is a hollow, porous member having a port formed therein which is connected to a vacuum. A vacuum bag is hermetically sealed on the mandrel so as to define an enclosure over the workpiece. A power source is connected to the induction coil and, when activated, causes the coil to generate an oscillating magnetic field lying along the longitudinal axis of the mandrel. The magnetic field induces heat-generating eddy currents in the fibers of the workpiece which are oriented orthogonally to the magnetic field.

Induction heating of polymer matrix composites in an autoclave

Induction heating is utilized to heat polymer matrix composite fiber strands containing electrically conductive fibers. This is accomplished with an apparatus having a helical induction coil and a matching helical guide tube situated adjacent to the induction coil. Composite fiber strands are drawn through the guide tube which is made of a non-electrically conductive, nonmagnetic material. Electrically conductive rollers, positioned next to the entrance and exit of the guide tube, form an electrical circuit with the electrically conductive fibers. This permits currents to be induced in the fibers when the coil is activated, thereby heating the fiber composites. The guide tube can be thermally insulated and flushed with an inert purge gas. Alternatively, the guide tube can be made of an electrically conductive or ferromagnetic material so that heat producing currents are induced in the guide tube, and the composite fiber strands are heated by conduction. In this case, the fibers need not be electrically conductive.

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Rexford, NY, United States of America

Philip C Sturman, Jr