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Web Handling & Converting

Blogmaster: Dr. David Roisum


Tension/Drive Control

26
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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09
A wonderful article on disc brake noise posted by and gratefully shared by Bryon Williams of Montalvo.
28
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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07
It does little good to say your machine is crooked (even if it is).  That would be just whining.  Nobody likes whiners.  Instead, we should strive to be good complainers instead.  By complaint, we mean so specific as to be literally able to touch the thing that is wrong (crooked)...

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05
Web Path Changes During Speed Changes
Path changes during speed changes are a common (and usually avoidable) problem.  In winding the resulting defect is given a special name:  acceleration offset.  Unfortunately, the name does not reflect the true mechanics of the problem.  It is not acceleration per se.  Inste...

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23
(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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17
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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15
Wishful Thinking – Tension and Wrinkling
Getting stuck in problem solving is epidemic.  We get stuck on wishful thinking, optimism, hope and a host of other ‘positive’ attitudes.  Now, don’t get me wrong, I am not suggesting that these traits are necessarily bad, only that they can be when you get stuck in a rut...

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09
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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07
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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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.