Abstract: A laminating machine for laminating layers of plastic film about an insert has cold feed rollers, a preheater and heated expeller rollers. The workpiece to be laminated is fed to the preheater by the feed rollers and is heated to a temperature just below the melting point of the adhesive on the plastic film. The heated workpiece is then fed to the hot expeller rollers which apply heat and pressure to finish melting the adhesive and squeeze any air bubbles out of the workpiece. Temperature controls assure that no melting and thus, no pre-lamination occurs at the preheater. The preheating step results in a laminating machine with high throughput of high quality laminations, even with inserts impervious to air.

Abstract: A heating element for a plastic film laminator has a cylindrical base member. A heating layer of conductive resin such as conductive silicone is molded to the base member. An outer layer of dielectric material may cover the heating layer. Resistive electrical contacts are connected to the heating layer. An electrical power supply is connectable to the contacts. The resistive contacts create a voltage drop within the contact along the axis of current flow. This lowers the current density at the interfaces of the contacts and heating layer to prevent localized overheating of the conductive resin.

Abstract: A heating element for a plastic film laminator has a base member, either flat or cylindrical. An insulating layer of non-conductive material is formed on the base member. A heating layer formed of conductive resin such as conductive silicone is molded to the base member, with the insulating layer between the base and heating layer. An outer layer of non-conductive silicone may cover the heating layer. Electrical contacts are connected to opposite sides of the heating layer. An electrical power supply is connectable to the contacts. Current passing through the heating layer provides uniform heating which is transferred to the plastic to be laminated.