| 摘要 |
A sealing assembly is employed to clamp together layers of a layered web, such as two layers of flexible laminate plastic film, and to bond and cut the layers by applying heat and pressure. The sealing assembly may include a pair of jaws, one of which has a sealing head with a conductive knife protruding from a tapered dielectric supporting base. The knife has a high thermal conductivity relative to the supporting base. A current supplied through the knife heats it and the heat of the knife raises the temperature of the supporting base to a baseline temperature. When the head abuts the layered web, a spike current through the knife raises its temperature momentarily to melt through, and therefore sever, the web.
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