Web201.41b Web Extremes – Narrow v Wide
***201.41b – Web Extremes – Narrow v Wide
05 Slides Duration 03.57 v 15.03.12
201.41b.01 – Title Slide
Welcome to Web-Handling. My name is Dave Roisum. In this second clip in a series we discuss in what ways narrow webs are challenging and in what different ways wide webs are challenging.
201.41b.02 – Wide – Most Important Concerns
Before we get to web-handling and converting, however, I must again stress that non web-handling concerns are usually far more important. These concerns are similar to speed that we discussed in the last clip. That is, you must have sufficient market to ‘feed the beast’ as they say. Second, wide webs are often cut into narrower finished products. In these cases, nesting waste needs to be factored into production scheduling and economics. Also, reliability must be greater or much greater when going wide. For some, increasing speed may be an easier way to get more production.
201.41b.03 – Width Comparison
Don’t you just hate when a speaker puts up a busy chart and just reads the words? Me too, so I won’t. You can pause the video and get the details as you need.
Still, as with speed, we must make a somewhat artificial delineation between narrow and wide. Here I will add a third column for ribbon like.
Roller design is greatly affected by width. Not surprisingly, wide rollers need to be bigger in diameter. Sizing is detailed in my Mechanics of Rollers book and the Roller Bending Calculator by AbbottApp. Roller mounting also changes from pure cantilevering on ribbons to always simply supported on wide machines. Roller alignment challenges are all over the map. Curiously, narrow webs are usually the biggest challenge here for a variety of physical, economic and cultural reasons. I have written much on alignment recently. We also have an AbbottApp for alignment as well called Wrinkle Predictor. Finally, air handling varies greatly with width and this subject is covered in great detail in my roller book and my Web101 course.
Those of you who have taken my Web101 course will also recall that spreading of narrow webs is seldom or never needed, and this is a good thing because we have few spreaders to work in that narrow web regime. In short, spreading and wrinkling concerns increase with web width.
There are many converting detail differences between narrow and wide webs that we won’t discuss much here.
What I would like to close with is the stern warning that the demands on the web itself are at least as great as on web handling. That is wide webs demand much better and much more level profile and we often have difficulty delivering.
201.41b.04 – Difficult ‘Profiles’
Here I offer yet another stern warning having to do with profile, but this time it is intentional profile variation as part of product design. Here I will just mention that going two-wide is not just twice as hard, it can be an order of magnitude more difficult because there are many problems such as registration and wrinkling that do not exist in that form on one-wide webs. There are many other products from hell that I cover in my seldom-taught Web101 module that I call DFM or Design For Manufacturability.
201.41b.05 – Questions?
Thank you so very much for watching this module in my plant practical video clips. Stay tuned for more web handling extremes.