By Dr. David R. Roisum  
  
We will define path control problems as whenever the web’s CD position is not stable with time.  We will also see that in many cases the web CD position is ALSO not stable with down web MD position as well. True, your operator and your quality control department will not necessarily call these path control problems. They are more likely to use rejectable defect names such as roll interweaving, that we discussed in the last clip, or rough roll edges in winding as will be discussed in an upcoming clip, or poor color-to-color registration on printers or many many others.Still, these examples are all path problems that are sometimes easier to diagnose as path problems than by using a narrower specific defect focus.
 
Web201.68l: 
https://www.youtube.com/watch?v=bXsMKpOoAac