Web201.44a – Bowed Roller Failure Modes – Unrealistic Expectations
***201.44a – Bowed Roller Failure Modes – Unrealistic Expectations
04 Slides Duration 02.24 v 15.08.25
201.44a.01 – Title Slide
Welcome to web handling. My name is Dave Roisum. The bowed roller may be the most common spreader. In this clip we begin a series on failure modes peculiar to this device.
201.44a.02 – Wrinkling
The number one usage of any spreader, bowed rollers included, is to help with wrinkling. Not surprising then that it is the number one way they will disappoint.
First, it is possible that the wrinkling insult is simply too big for a bowed roller. A classic example here is expansions exceeding 1% in width such as nylon going through a water bath. Another example is with heavy products such as textiles where the forces provided by a bowed roller may not be enough. Large expansions may require more powerful spreaders such as expander rollers or tenters.
Second, many people think of removing wrinkles instead of preventing them in the first place by placing an appropriate spreader in the appropriate place. As we learned at the beginning of that module in our Web101 class, removing a wrinkling is 100X harder than preventing it in the best of cases. In the worst of cases, such as paper and other products, a crease will destroy the product or destroy the runnability of the process.
201.44a.03 – Bagginess
Overall, bagginess is the number one cause of waste and delay in the web industries. Therefore that is another source of great disappointment for many.
As we learned in Web101, spreaders can not fix or remove bagginess.
Also as we learned in Web101, the mechanism by which bowed rollers may help is extraordinarily limited. The benefit, if there were any, is quite temporary. Ending at or before the next roller downstream.
201.44a.04 – Questions?
Thank you so very much for watching this module in my plant practical video clips. Stay tuned as we explore further failures of the ubiquitous bowed roller.
Photo Courtesy of Spencer Johnston