Apparatus for making bag assembly

A method of forming a bag assembly by RF welding, comprising the steps of:

• inserting a tubular insert into a lumen of a tube to form a tube assembly,
• placing opposing sheets and the tube assembly at least partially received between the sheets between first and second opposing die members of a welding apparatus, the first die member including a first tube-welding electrode and a first perimeter-welding electrode and the second die member including a second tube-welding electrode and a second perimeter-welding electrode,
• generating from a single source of RF energy a high frequency electric field having a first strength between the tube-welding electrodes of the opposing die members and a second strength less than said first strength between the perimeter-welding electrodes of the opposing die members,
• subjecting the tube assembly and corresponding portions of the sheets surrounding the tube assembly to the high frequency electric field of said first strength for a predetermined amount of time to weld the sheets to the tube along a tube-weld,
• subjecting corresponding portions of the sheets between the perimeter-welding electrodes to the high frequency electric field of said second strength for said predetermined amount of time to weld the sheets together along a bladder perimeter-weld,
• wherein said subjecting steps are performed simultaneously so that the bag assembly is formed in one welding operation.