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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; even a scratch can be a site for initiation.  I recall from my days at Beloit Corp that journal materials were first tested in high cycle fatigue. When I say high cycle I mean 10^8 cycles, not the wimpy 10^6 cycles found in engineering textbooks that was pioneered by the automotive and aerospace that were still playing metallurgical catch-up.  The tested fatigue endurance limit was then coupled with extremely generous safety factors, a little over 5 depending on the alloy.  Of course, we considered combined (bending plus torque) stress concentration factors.  Thus the first line of defense was highly engineered design.

The next line of defense was Safety Alert bulletins regularly issued to maintenance departments.  (But a single example of hundreds is referred to in this paper on corrosion and corrosion fatigue for pressure vessels).  These were bullet points of how to care for journals so that they lasted the better part of a century without exploding in someone’s face.  Bullet points not unlike Metso’s Reel safety - real concerns for aging equipment.
Posted in: Design, History, Maintenance, Rollers, Safety, Winding
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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.