a machine for facilitating the simultaneous heating , bonding or sealing of a group of thermoplastic articles retained within a rotary sealing system . first and second rotatable workpiece carriers are arranged to transport the workpieces to be bonded , step - by - step , from loading stations to a heating station , and subsequently , to a bonding station , thereby accomplishing a plurality of operations on a simultaneous basis . the same drive mechanism used to incrementally rotate the workpiece carriers also imparts a reciprocating motion to the heating element and an arcuate reciprocating motion to the workpiece carriers for first applying heat energy to the workpieces for a predetermined time interval and for subsequently applying compressive forces to the heated workpieces undergoing bonding and thereafter releasing the now - joined workpieces from the carriers . there is a minimal movement required of the work , thus with the simultaneous occurrence of loading , heating , and bonding , the rate of speed for the system is substantially increased .