Web ​Handling And Converting

The approximate difference between no problem and no product.
Bagginess allowable by next customers (winder or end use):  2-20 parts per 10,000 as measured by the strip test or other method
Caliper/gage/thickness variation allowable by winder:  1%-10% (less in foil, more in blown film that is oscillated continuously 360 degrees.
Hygrothermal expansion without excessive wrinkling:  0.1%-1%

Wrinkles are, arguably, the number one cause of waste, delay and customer complaints in the web industries.  That (set of) defects may claim around $1 billion worldwide annually.  Yet, despite all of this our detection methods are usually pretty rudimentary:  operator eyeballs.  Yes, you can often see many forms of wrinkling better than almost any other instrumentation method, but only if someone is looking continuously across the entire width and has good (low angle) lighting in that inspection area.  Blink and you miss it and it is off to your customer who more likely has better eyes.

An alternative to consider is simple, cheap and usually rock solid:  dual edge sensors.  The smallest wrinkle will tuck in one or both edges.  This is easy for the sensors to see as a ‘width’ change as the resolution of many of the sensors are on the order of a hair’s thickness (0.005”, 125 microns).  The only limitations is that the incoming material would have to have slit edges and that the incoming width variation is not large to begin with.  Anyone see a product development and marketing opportunity?  If you can’t get that satisfaction from the component suppliers, it would still be easy enough to Macgyver together by any self-respecting instrumentation tech.
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