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Blogmaster: Dr. David Roisum

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Maintenance

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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31

Tension Guidelines

Posted by David Roisum on January 31, 2012
Tension Guidelines
Respected sir, I came upon a TAPPI standard that tension should be 10-25% of yield strength. 1. Is there any scientific rule to setting these value or are they heuristic? 2. What rule shall we follow in printed electronics industry? I am especially interested in the allowed variation fro...

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

The Optimum Component Repair Time

Posted by David Roisum on January 26, 2012
The Optimum Component Repair Time
From the previous post we noted that nearly everyone has an idea of the costs of maintenance.  (We used cover grinding as an example, but the application is much wider than this).  The more frequently you grind the greater the maintenance costs.  If that is the only cost management ha...

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Posted in: Maintenance, Problem Solving, War Stories in Web Handling
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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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10

Crown Correction

Posted by David Roisum on January 10, 2012
My venerable Mechanics of Rollers book has a couple of omissions that I have long regretted.  They are both, fortunately, nicely published in Metso’s Up and Running web page.  The newest edition on Tips for Maintaining Rubber Covered Rollers has more than advertised by the title.&nbs...

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Posted in: Design, Maintenance, Nips, Rollers
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27

Roller Grinding

Posted by David Roisum on November 27, 2011
An article from Metso on the process of (re) grinding rollers large and small.  Nice discussion of dubbing/taper/relief of the ends of rubber covers. http://www.metso.com/pulpandpaper/MPwUpRunning.nsf/WebWID/WTB-050202-2256F-08A73?OpenDocument&ad=AotC_banner_20111123
Posted in: Maintenance, Rollers
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19

Up and Running: Rolls and Rollers

Posted by David Roisum on November 19, 2011
Metso in conjuction with TAPPI publishes a monthly e-newsletter call Ahead of the Curve that occasionally has web handling content.  Two recent articles include: Roll structure analysis: WIT-WOT and gap test Dynamic and static balancing of rolls - how, why and when
Posted in: Maintenance, Rollers, Winding
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01

Mandrel/Spool/Roller Journal Safety

Posted by David Roisum on October 1, 2011
Thankfully, journal failures are rare.  However, when it does occur it is often catastrophic; things come loose; things that have mass and speed; things that clearly pose a safety hazard when they come loose. Most journal failures are due to fatigue at stress risers at the journal fillets; eve...

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Posted in: Design, History, Maintenance, Rollers, Safety, Winding
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13

How NOT to Cook Bearings

Posted by David Roisum on June 13, 2011
There are at least three concerns with bearings that must operate at high temperatures.  The first, and probably the easiest, is that the steel must be durable and stable at those temperatures.  The second is that the acceptable fits between the outer race and the housing as well as betwee...

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Posted in: Design, Maintenance, Rollers
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12

Reel Spool Safety

Posted by David Roisum on June 12, 2011
Reel spools (and sectional slitter table rolls on winders) can accumulate 10^9 cycles during their half century life.  This is far greater than the mere 10^6 cycles that is standard for fatigue studies in automotive and aerospace.  Furthermore, fatigue is just one of many ways journals can...

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Posted in: Design, Maintenance, Rollers
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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.