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Web Handling & Converting

Blogmaster: Dr. David Roisum

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Measurement

26

Load Cell Roller Wrap Angle

Posted by David Roisum on April 26, 2012
Load Cell Roller Wrap Angle
The load cell manufacturer can not make general recommendations for wrap angle.  The value for minimum wrap angle depends on all of the things needed for sizing (selecting maximum capacity) a load cell such as tension, width, roller and fixture tare weights and so on, all of which can not be kn...

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Posted in: Design, Measurement, Rollers, Tension/Drive Control
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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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09

Calculating/Determining Laminator Tensions

Posted by David Roisum on February 9, 2012
What should be the unwinding tension for 12 micron PET film and for 30 micron Polyethylene film.  Please give me the formula for calculating the rewinder tension for the laminate. I will use page 5.10 from the 2010 version of the Web101 notes.  I apologize for the mixed units, but we will...

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Posted in: Design, Materials, Measurement, Tension/Drive Control, Winding
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20

Rubber Cover and Chemical Incompatibilities

Posted by David Roisum on January 20, 2012
Metso has published another roller related article, this time a small laundry list of some rubber cover incompatibilities with certain chemicals found in the paper industry.  You can find a more in-depth discussion of the topic in the Rubber Roller Group Handbook and perhaps even more from your...

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Posted in: Design, Materials, Measurement, Rollers
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01

Paper Length and Moisture

Posted by David Roisum on December 1, 2011
I would like to know why the paper length of wound roll decreased about 200 to 250 meters after increasing the moisture contents about 1% on newsprint paper 45GSM? The coefficient of hygroscopic expansion for paper is about 0.1% for every 1% change in moisture for typical levels of moisture of 4-8%...

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Posted in: Measurement, Winding
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22

Baggy Web Conversation

Posted by David Roisum on November 22, 2011
The following is historical fiction.  One where certain essential details are accurate, but the ‘conversation’ has been rewritten to protect the guilty. Dear Dr. Roisum, I was your student in a Converting School back in 20__. We now have a difficult web-handling problem caused ...

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Posted in: Materials, Measurement, Problem Solving, Rollers, Spreading, War Stories in Web Handling, Winding, Wrinkling & Flatness
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17

Roll Hardness Profiles - Alternatives

Posted by David Roisum on November 17, 2011
Recall from the previous post, that effective culling is economically better for both customer and supplier than are customer complaints.  Start culling now rather than wait for some magic bullet cure so the benefits are achieved sooner rather than later.  Culling can also help with possib...

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Posted in: Measurement, Problem Solving, Winding, Wrinkling & Flatness
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15

Roll Hardness Profiles - Getting Started

Posted by David Roisum on November 15, 2011
It is great that in paper we have measurements that might correlate to a large list of troubles.  Aside from the extremes such as tissue and board, the simple delta of hardness across the roll can be predictive of such debilitating defects as bagginess, corrugations, runnability and many others...

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Posted in: Measurement, Problem Solving, 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.