Method and Apparatus For Making Bags

Abstract

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.

1 - 6 . (canceled) 
     
     
         7 . A method of making bags comprising:
 receiving a web;   forming a first seal on the web using a seal bar on a rotary drum;   forming a weakened area adjacent the first seal for at least a portion of the time the first seal is being formed by providing power to a heating wire disposed in a plurality of holes disposed along a line in the cross direction.   
     
     
         8 . The method of  claim 7 , wherein forming a weakened area includes forming a perforation. 
     
     
         9 . (canceled) 
     
     
         10 . The method of  claim 7 , further comprising monitoring a signal indicative of heat in the wire and controlling power applied to the wire in response to the signal. 
     
     
         11 . The method of  claim 10 , wherein forming a weakened area includes forming a line of weakness that varies in intensity. 
     
     
         12 . The method of  claim 11 , wherein forming a weakened area includes separating adjoining bags. 
     
     
         13 - 15 . (canceled)