A frictional weld joint couples together first and second body portions of an article. The first body portion has a first nominal wall thickness and a first joint surface. The second body portion has a second nominal wall thickness and a second joint surface. A total bead height is defined between the joint surfaces. A first bead extends from the first joint surface defining a first bead height. A second bead extends from the second joint surface and is coupled to the first bead. A final second bead height is defined between the first bead and the second joint surface. A ratio of the first bead height to the final second bead height is of from about 0.40 to about 1.70. A ratio of the total bead height to at least one of the first and second nominal wall thicknesses is equal to or less than 6.00.

This invention is directed to multiple sealing bars to seal articles moving on a conveyor (2) inside a sleeve (4) that forms a continuous film tube (5). Retracting conveyors act to collapse the tube between the articles so that the collapsed portion of the tube can be sealed. The synchronization of the sealing bars with the movement of retracting conveyors allows for a continuous motion machine where the products inside the film do not stop.