Apparatus and method for minimizing waste and improving quality and production in web processing operations by automatic cuff defect correction

Abstract

Apparatus and methods are provided to minimize waste and improve quality and production in web processing operations. The apparatus and methods provide defect detection both before and after application of component patches to a traveling web to create a product. Web defect detection may be provided by way of at least one visual inspection station located upstream from the patch applicator. Patch defect detection may be accomplished by way of a visual inspection station located proximate the patch applicator. If defects are detected in either the traveling web or the component patch prior to patch application, patch application may be prevented until both a satisfactory web and patch are provided. If defects are detected after patch application, the resulting product may be culled. Furthermore, the apparatus may be provided with diagnostic software to warn against extant or imminent machine complications.

The invention claimed is: 
     
       1. A method for correcting defects in a running web comprising:
 creating a running fold having a cross-direction fold width in an initial condition along a machine direction of a running web supplied at a feed rate; 
 monitoring said running fold for a predetermined change in cross-direction fold width of said fold width from said initial condition; 
 upon detection of said predetermined change in said cross-direction fold width of said fold width from said initial condition, initiating a correction sequence to restore said running fold to said initial condition; wherein said correction sequence further comprises the steps of: 
 engaging a mistrack correction roller against the running web; and 
 disengaging said mistrack correction roller from the running web. 
 
     
     
       2. A method according to  claim 1 , wherein, if said fold width is too narrow, said correction sequence further comprises the step of urging a folding plow into engagement with said running web. 
     
     
       3. A method according to  claim 1 , further comprising a step of increasing said feed rate after engaging said mistrack correction roller and then decreasing said feed rate after the step of increasing said feed rate. 
     
     
       4. A method according to claim 1, wherein, if the fold width is too narrow, the correction sequence further comprises the step of applying tape to said running web via a tape applicator, in order to correct said fold width back to said initial fold width. 
     
     
       5. A method according to claim 1, wherein engaging said mistrack correction roller against said running web is disabled if a machine speed is below a predetermined speed. 
     
     
       6. A defect correction system for correcting defects in a fold of a running web having elastic strands thereon, the system comprising:
 an arrangement of a drive roller and idle roller configured to translate the running web in a machine direction at a feed rate;   a guide roller positioned to receive the running web as it translates in the machine direction;   a correction roller configured to selectively engage the running web and elastic strands;   a folding board positioned downstream from the guide roller and configured to create a running fold in the running web that has a cross-direction fold width along the machine direction;   a defect detection system configured to monitor the running fold for a predetermined change in cross-direction fold width from an initial fold width; and   a controller programmed to:
 receive an input from the defect detection system comprising the cross-direction fold width of the running fold; and 
 identify the predetermined change in cross-direction fold width from the initial fold width; and 
   wherein, when the predetermined change in cross-direction fold width is identified, the correction roller operates to engage with the running web and disengage from the running web.   
     
     
       7. The system of claim 6 wherein the defect detection system comprises a camera. 
     
     
       8. The system of claim 6 further comprising a plow that is movable to selectively engage the running web. 
     
     
       9. The system of claim 8 wherein the plow engages the running web when the cross-direction fold width is identified as being narrower than the initial fold width, in order to correct the fold width back to the initial fold width. 
     
     
       10. The system of claim 9 further comprising a tape applicator configured to apply tape to the running web when the cross-direction fold width is identified as bell narrower than the initial fold width, in order to correct the fold width back to the initial fold width. 
     
     
       11. The system of claim 6 wherein the drive roller is configured to increase the feed rate of the running web when the correction roller engages with the running web and to decrease the feed rate of the running web when the correction roller disengages from the running web. 
     
     
       12. The system of claim 6 wherein the defect detection system is configured to monitor a presence and positioning of the elastic strands on the running web to detect an absence of one or more of the elastic strands or a mistrack of one or more of the elastic strands on the running web. 
     
     
       13. The system of claim 12 wherein the controller is programmed to:
 receive an input from the defect detection system comprising the presence and positioning of the elastic strands on the running web; and   identify the absence of one or more of the elastic strands or the mistrack of one or more of the elastic strands on the running web.   
     
     
       14. The system of claim 13 wherein, when the absence of one or more of the elastic strands or the mistrack of one or more of the elastic strands on the running web is identified, the correction roller operates to engage with the running web and disengage from the running web.