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Web Handling & Converting

Blogmaster: Dr. David Roisum

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Design

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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24

Wrap Angle Rock Around the Clock

Posted by David Roisum on April 24, 2012
Wrap Angle Rock Around the Clock
At uber, ultra, very, big, great risk of over-generalizing and over-simplifying, I would like to offer you some ideas on some application range for wrap angles.  The application ranges include idlers, tendency and driven rollers and include systems that are and are not wrinkle-prone.  Here...

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Posted in: Design, Rollers, Spreading, Wrinkling & Flatness
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30

Speed Limit - Economics

Posted by David Roisum on March 30, 2012
So, we now get to the more limiting speed limit; economics.  You have to feed the beast with orders.  The big problem is with cold starts.  (Men and) machines take some time to get started; in the mean time you are paying people to make nothing, at best, or waste at worst.  Worki...

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Posted in: Design
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28

Speed Limit - Machine

Posted by David Roisum on March 28, 2012
Aside from wound roll vibration, most machine speed limits are few.  These include such things as drive power, bearing rpms and critical speed (a topic that has enormous misunderstanding that may be worth revisiting in a future post).  Since the additional mechanical costs of a machine tha...

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Posted in: Design, Rollers, Tension/Drive Control
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26

Speed Limits - Web Handling

Posted by David Roisum on March 26, 2012
Speed Limits - Web Handling
There are only two speed limits in web handling that I am aware of.  The first is air entrainment.  This is easy to counter on rollers by roughening them to give them air-handling capabilities.  (You may have to avoid annular or spiral grooves for very thin products, as they might ten...

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Posted in: Design, Rollers, Winding
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23

(Guide, Load Cell) Sensor Location

Posted by David Roisum on February 23, 2012
(Guide, Load Cell) Sensor Location
Everyone in the know, knows that the edge sensor belongs right next to the (moving) roller for all guide types for two reasons, even if somewhere else is really the position of greatest concern.  The first is to support the web so that flutter and curl are squelched so that they don’t con...

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Posted in: Design, Guiding, Tension/Drive Control
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17

Wishful Thinking – Winding Taper and TNT’s

Posted by David Roisum on February 17, 2012
Wishful Thinking – Winding Taper and TNT’s
Continuing the theme of the previous post, we now turn to an even stickier bit of wishful thinking.  That is, the desire/hope/wish/belief/etc that winding defects can be cured (to everyone’s satisfaction) or at least noticeably remedied by changing the winder TNT (Tension, Nip, Torque) cu...

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Posted in: Design, Nips, Problem Solving, Tension/Drive Control, Winding
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13

Cooling Rubber Covered Rollers and School

Posted by David Roisum on February 13, 2012
Cooling Rubber Covered Rollers and School
Metso’s Up and Running E-news has another roller related article.  This one is on Guidelines for Internal Water Cooling of Rubber Covered Rolls.  While it is considered tasteless to critique an article when you yourself have not written anything better (or at all) on the subject, I o...

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Posted in: Design, Maintenance, Nips, Rollers, Temperature/Moisture Effects
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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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07

Web Smoothness, COF, Tension and Telescoping

Posted by David Roisum on February 7, 2012
We recently encountered customer complaint regarding roll telescoping.  Presently, we have the same tension settings for two different types of foil that have different roughness values. Would you recommend a higher or lower rewind tension for smoother foil surface (less roughness value)? Whil...

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Posted in: Design, Materials, Problem Solving, Tension/Drive Control, Winding
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Blogmaster

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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.