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Web Handling & Converting

Blogmaster: Dr. David Roisum

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Web Manufacturing

03

High edges, narrow layon rollers and other confusion

Posted by David Roisum on May 3, 2012
Q: A colleague of mine recently stated that use of a lay-on or rider roller that is not as wide as the web is 'common practice'. He sees this as a form of 'winding optimization', whereas the word that I would use is more like 'accommodation'.  We are winding a delicate .001" thick film that is ...

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Posted in: Nips, War Stories in Web Handling, Web Manufacturing, Winding, Wrinkling & Flatness
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20

Profile and Winding Tightness

Posted by David Roisum on April 20, 2012
Profile and Winding Tightness
The winder TNT settings plus material properties determines the AVERAGE winding tightness across the width.  Profile variation determines how the tightness is distributed.  Seldom in the real world can we vary average winding tightness by much more than 2:1, even if we throw all of the kno...

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Posted in: Measurement, Problem Solving, Web Manufacturing, Winding
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18

Weight Profile Detection

Posted by David Roisum on April 18, 2012
Perhaps the most useful profile for troubleshooting is (basis) weight.  Weight (caliper, density, gage, thickness etc) variations across the width are one of the most universal causes of waste/delay/trouble in the web industries.  Unfortunately, weight profile is difficult to measure with ...

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Posted in: Measurement, Problem Solving, Web Manufacturing, Winding
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16

Profile is a Variation of ___ Across the Width

Posted by David Roisum on April 16, 2012
Profile is a Variation of ___ Across the Width
Where ___ could be any measureable property.  It is an extremely useful concept to get started in problem solving.  If you have a frown/smile shaped profile, the thing that made it must have a similar smile/frown shape.  If the profile is tapered from one end to another, then the root...

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Posted in: Measurement, Problem Solving, Web Manufacturing
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22

Wound Roll Wrinkles – Top of the Roll

Posted by David Roisum on March 22, 2012
The top of the wound roll is especially wrinkle prone.  Gage variations build to make wound roll geometries that are orders of magnitude cruder than rollers.  The nip and thus tightness of many surface winders increases thus making tighter wound rolls that are less able to cover up manufac...

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Posted in: Web Manufacturing, Winding, Wrinkling & Flatness
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24

The Sawtooth and Excessive MTBS (poor maintenance practice)

Posted by David Roisum on January 24, 2012
The Sawtooth and Excessive MTBS (poor maintenance practice)
The Third Law of Thermodynamics and Murphy’s Law both require that things break down.  When do you get around to fixing them?  Maintenance culture tends to fall into one of two patterns.  The first is to fix it when it has to be fixed, i.e., the machine will no longer run saleab...

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Posted in: Maintenance, Problem Solving, Rollers, War Stories in Web Handling, Web Manufacturing
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06

Baggy Web Survival Strategy

Posted by David Roisum on September 6, 2011
The first time you get baggy material, send the roll back to the supplier. What will they do? They will pay the claim. What will they not do? Fix the problem. The second time you get baggy material, try to find some measure of bagginess and a threshold of pain. Candidates include roll hardness...

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Posted in: (Other) Converting, Problem Solving, War Stories in Web Handling, Web Manufacturing, Wrinkling & Flatness
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30

Baggy Webs - The Primary Cause

Posted by David Roisum on August 30, 2011
Baggy Webs - The Primary Cause
The primary cause of bagginess is caliper/gage/thickness variation that builds up as ridges on the wound roll that then differentially yield (stretch) the web into bagginess. Since this is a TTP (Time Temperature Pressure) problem, winding looser would help. So too would converting quickly (though...

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Posted in: Web Manufacturing, Winding, Wrinkling & Flatness
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07

Infrared

Posted by David Roisum on August 7, 2011
Infrared
Of all high-end instruments I might wish for but seldom find in my troubleshooting visits is an infrared camera.  However, my last two clients both not only had a camera, they both used the same make and model of hand-held IR camera AND, they were both INDESPENSIBLE for unlocking the problems w...

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Posted in: Tension/Drive Control, Web Manufacturing
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03

Defects that Favor a CD Position

Posted by David Roisum on March 3, 2011
Defects that Favor a CD Position
Doesn’t that picture of air buckles look so pretty?  The defect is plastered uniformly across the entire width!  As odd as it might seem, that is probably best for the troubleshooter.  If you are slitting (rewinding) you would like to have that defect show up evenly on all rolls...

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Posted in: Problem Solving, Web Manufacturing, Winding, Wrinkling & Flatness
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Blogmaster

David Roisum photo

Dr. David Roisum

Dr. Roisum is a well-known authority in the area of web handling and converting. He has authored seven books, including Winding, Rollers and Web-Handling and has coauthored or edited several others. He was a technical editor for Converting Magazine with a monthly column entitled "Web Works." An accomplished professional speaker and instructor, Roisum has been praised for his skill at translating highly technical information into a common sense practical reference. Dave has been honored by TAPPI with their Finishing & Converting Division Award, Thomas W. Busch Prize and Finest Faculty awards and is a TAPPI Fellow. Dave received his Ph.D. from the Web Handling Research Center where he later became an Industrial Advisory Board member.

Dave has worked for the Beloit Corporation as a designer of winding machinery and later as a manager of research, and for Kimberly-Clark as a converting expert serving all business units. He is now a principal of Finishing Technologies Inc., providing consulting services to more than 300 clients who convert or manufacture: paper, film, foil, nonwovens, textiles and many other materials. He has accumulated much practical experience working in nearly 1,000 plants over the course of more than three decades.