Patent ID: 7115086

Claim:
A method of forming seal-cuts to form a bag for a bulky article by sealing ends of a film envelope comprising a folded sandwich of a layer of padding element disposed interbetween a pair of layers of thermoplastic film; the method comprising the steps of: interposing the envelope between a sealer bar and an anvil, the sealer bar having an initial temperature below a softening point of the film and comprising a sealing surface including a ridge projecting therefrom for increasing clamping pressure along a cut line; applying a selected clamping pressure across a clamping profile wider than the sealing surface of the sealer bar for clamping the layers of the film envelope between the sealer bar and the anvil, the selected clamping pressure being sufficient to substantially fully compress the layer of padding element; then heating the sealing surface to a selected sealing temperature, whereat the layer of padding element is captured in the layers of thermoplastic film in the region of the sealing surface and the envelope is at least partially severed in the region of the ridge to define two bags; then cooling the sealer bar to a temperature below the softening point; maintaining the selected clamping pressure across the clamping profile during the cooling step to set the layer of padding element firmly within the bags; and removing the clamping pressure.