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Blogmaster: Dr. David Roisum

Entries for 'David Roisum'

18
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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16
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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12
I have worked on uncountable problems during my visits to about 1,000 plants.  There are three situations that are most troubling. 1).  When blame is put on a blameless party 2).  When the boss insists on fixing it but not to change anything of substance 3).  When physics does...

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Posted in: New & Noteworthy
10
There are only 3 problems I put on my personal ‘run and hide’ list.  (These are the type that when the boss is looking for volunteers, don’t raise your hand). 1)     baggy webs 2)     web breaks 3)     self-excited...

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Posted in: Problem Solving
09
A wonderful article on disc brake noise posted by and gratefully shared by Bryon Williams of Montalvo.
05
Many states have Good Samaritan laws that protect well-meaning first responders who try to help accident victims from liability and lawsuit.  However, there is no Good Samaritan exemption from the brutal laws of physics.  So, even moving in the correct direction could make things worse.&nb...

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03
Which is a worst-case reliability for missed transfers on a turret winder or unwind:  90.0%, 99.0% or 99.9?  Surprisingly, it may very well be that 99% is worse than 90% and it has to do, as everything should, with economics.  If you miss 1 in every 10 transfers, you will not suffer f...

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30
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
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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26
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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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.