A machine and method for making bags is described and includes a web, traveling from an input section to a rotary drum, to an output section. The rotary drum includes at least one seal bar, having a first sealing zone, and an adjacent weakening zone. The weakening zone may be a heated perforator, includes a heating wire, or be disposed to create an auxiliary sealed area. The heating wire can have, connected thereto, a source of power that is at an adjustable voltage or magnitude, and/or pulsed, and/or a feedback loop. The heating wire may be an NiCr wire and make intermittent contact with the web and be disposed in an insert. The weakening zone may create a line of weakness that is uniform or varies in intensity, is a separating zone, or includes a heat film, a toothed blade, a row of pins, a source of air, or a source of vacuum. The sealing zones may include temperature zones, cartridge heaters, cooling air, or heated air, or a source of ultrasonic, microwave or radiative energy.

A method and a device for heat sealing multiple plies of a laminate from which gable top packaging can be produced, wherein the laminate has a carrier layer made of electrically non-conductive material and a sealing layer made of thermoplastic material on at least one surface of the laminate. To heat seal multiple plies of a laminate in a high-frequency alternating electric field, the alternating electric field is generated by a first lead of an HF voltage supply in a first sub-region of the sealing region and is generated by a second lead of the HF voltage supply, differing from the first lead, in at least a second sub-region of the sealing region, so that a different heat distribution is obtained over the sub-regions of the sealing region.

A method and an apparatus for welding together a first object and a second object. The method comprises applying a layer of carbon nanotubes onto a surface of the first object and bringing the first object and the second object into contact, such that the layer of carbon nanotubes on the surface of the first object is in contact with a surface of the second object. The method further comprises applying a voltage to the layer of carbon nanotubes, such that an electrical current flows through the layer of carbon nanotubes, wherein material of the first object adjacent to the layer of carbon nanotubes and material of the second object adjacent to the layer of carbon nanotubes is heated and melted by the electrical current and thereby welded together. Further, an apparatus for welding together a first object and a second object is presented.

An array of resilient floor tiles is assembled into a continuous sheet after being laid down. An array of included, sacrificial resistive wires is buried along the edges of the tiles and is controllably heated in order to cause welding of the edges of tiles across the paths of the wires to neighboring tiles. Subsequently the wires may be used to give the array integral tensile strength. The welded array is provided with greater strength for resisting use, expansive and contractile forces caused by environmental heat and cold and also long-term tile contraction owing to loss of plasticizer as may be seen with PVC-based tiles.