- Complete guide to all winder mechanical arrangements and control strategies
- Practical and theoretical know-how for predicting and avoiding roll defects
- Quantitative techniques for measuring and improving roll quality
- Accompanying CD-ROM provides computer models for many winding situations
List of Tables
Foreword by James N. Dobbs, 3M Company
1. Zen and the Art of Winding
- The TNT's of Winding
- Winder Classes
- Limits on Tension, Nip and Torque Differential
- The Effect of Class on Range of Wound Roll Tightness
- What is Tightness?
- How Does Winding Being a One-Knob Process Affect Winding Strategy?
- What Class is Best and How Many Knobs Do I Need?
- What About Taper or Roll Structure?
- How Do You Set Taper?
- A Few Words About Optimization-What is the Best Tension?
2. Some Winding Defects
- DFM Applied to Winding
- Getting Started
- What is a Defect?
- Corrugations or Ropes
- Gauge Bands or Ridges
- Hardness Variations Across a Roll
- Nip Induced Defects
- Offsets and Rough Roll Edges
- Out-of-Round Roll
- Starring and Related Defects
- A Note on Oscillation
3. Winder Arrangements
- Selecting a Winder
- Salvage Winders
- Turret Winders
- Duplex Winders
- Two Drum Winders
- Grooving, Traction Coated and Rubber Covered Drums
- Gap Winders
- Bigger is Better for Drums, Spools, Cores and Rollers
- Supporting Large Rolls on Drums
4. Roll Geometry and Properties
- Roll Diameter
- Roll Length
- Resolving Roll Length Discrepancies
- Roll Width
- Wound Roll Offsets and Rough Edges
- Telescoping and Dishing
- Roll Weight and Density
- Some Useful Roll Conversion Formulas
5. Simple Material Properties
- Basis Weight
- Caliper Profile-A Very Important Note
- Density or Bulk
- Other Web Material Properties of Winding Interest
- Other Roll Properties of Winding Interest
- The Fiber Core-The Foundation of Most Wound Rolls
6. Introduction to Wound Roll Modeling
- Stresses in a Wound Roll
- Anisotropy and Principal Axes
- MD or Tangential Modulus
- ZD or Radial Modulus
- In-Plane Poisson Ratio
- Poisson Ratios for Winding Models
- Basic Equations of Winding Models
- Winding Equation
- Core Modulus Ec-The Inner Boundary Condition
- Winding Tightness-The Outer Boundary Condition
7. Simple 1-D Models
- Early Models 1950-1985
- Hakiel's Models-1986
- Early Complex Models
- Early Experimental Verification
- The Hakiel Formulation
- Spongy and Fully Compressed Behavior
- Constant Tension versus Constant Torque
- Large Deformations
- Plane Strain versus Plane Stress Winding Models
8. 2-D Models and Gauge Variation
- Measuring Gauge Profile
- Early Models of the Effects of Gauge Variation
- True 2-D Models of the Effects of Gauge Variation
- Summary of the Effects of Gauge Variation
9. The Effect of Nip on Wound Roll Stresses
- Classes of Winders
- What is WOT?
- Early Experimental Evidence of WOT
- Early Models for WOT
- Comparative Study of Different Models for WOT
- WOT on Two Drum Winders
- Summary of Findings
10. The Effects of Air Entrainment
- Air Entrainment Between Webs and Rollers
- When Is Air Important Between Permeable Webs and Rollers/Wound Rolls?
- Some Practical Observations on Entrained Air
- Air Entrainment on Centerwinders
- An Introduction to Nip Rollers on Winders
- Modeling Air Exclusion by a Nip Roller
- Exhaust of Air Entrained From the Edges of a Wound Roll
- The Effect of Air Entrainment on Wound Roll Stresses
- Effect of Air Exhaust on Wound Roll Stresses
11. The Effects of Moisture and Temperature
- Time Constants for Movement of Moisture/Temperature in a Wound Roll
- Moisture/Temperature Profiles of a Wound Roll
- Thermoelastic Behavior in Wound Rolls
- Hygroscopic Behavior in Wound Rolls
12. Viscoelastic Behavior
- Creep and Stress Relaxation
- Viscoelastic Behavior
13. Defects Predicted by Winding Models
- Pressure Related Defects
- Bursts, Baggy Lanes, Ridges and Hardstreaks
- Modeling of Simple Slippage Related Defects
- Crepe Wrinkles
- Core Collapse
- Loose Cores and Core Stiffness
14. Dynamic Behavior at High Speeds
- Centrifugal Effects
15. Wound Roll Sampling and Inspection
- Why Measure?
- Measurement Methods
- Interchangeability of Measurements
16. Measures of Roll Hardness
- Billy Club and its Variants
- RhoMeter and RhoHammer
- Backtender's Friend
- Schmidt (Concrete) Hammer
- TAPIO RQP
17. Measurements of Interlayer Pressure
- Pull Tab
- Smith Needle
- Core Torque
- Axial Press Test
- Pressure Transducers
- Caliper In-Roll
- Acoustic Time-of-Flight
18. Measurements Based on Strain
- Cameron Gap
- Radially Drilled Holes
- Slit Roll Face
- Strain Gages
19. Density Based Measures
- Air In Roll
- Roll Density
- Density Analyzer-History
- Density Analyzer -Construction
- Density Analyzer-Theory of Operation
- Analysis of the Density Analyzer
20. Other Wound Roll Measures
- X-Ray Tomography
21. Wound Roll Measurement Considerations
- Is my Web Good?-Sampling Across the Width of the Roll
- Is my Roll or my Winder Good?-Sampling Through the Roll
- Is It the Winder's Fault?
- Is my Measurement Good?-Testing the Test
Appendix A-Units and Conversions
Appendix B-Selected Bibliography
Appendix C-Selected Calculations
About the Authors
By Dilwyn P Jones, Consultant, Emral Ltd, UK
This book is a useful purchase for any engineer or technologist concerned with winding thin materials, particularly paper, film and similar products. It brings together the expertise of two world-leading experts in the field.
Dr David Roisum is an inspiring teacher of winding principles and practice, and his seminars and courses are famous around the globe. I can almost imagine myself sitting in his class as I read the book! There are useful solutions to most winding problems, and the reasons why things are done are carefully explained. The sections of the book on machines and measurement especially show David’s sympathy for the employees faced with turning out good rolls, of ever-changing products, on machines that may not be quite up to the job. His folksy approach and everyday analogies make this a very appealing book; although some of the technical and not-so-technical terms may mean little to those outside North America!
Dr Keith Good has led the winding research at Oklahoma State University’s Web Handling Research Centre for 20 years. During this time he has published many research papers, and these form the core of the section on modelling. Building on the basic calculation of stresses within a roll after winding, he has proposed and experimentally confirmed the additional effects of a contact roller, air entrainment, thermal and viscoelastic effects. He is acknowledged as the top academic expert on winding world-wide. As well as the published academic studies, he is familiar with the development work and production issues in many of the companies that sponsor the Centre: these include most of the major US firms who produce and process web materials.
The key idea in the book is that the winding conditions and material properties determine the stresses within the roll during and after winding, and these determine the roll properties and whether it will exhibit one or more of a number of defects. Quality problems can often be solved by relatively simple changes to the winding conditions or equipment: there are suggestions in the book for overcoming most defects. However, the modelling of roll stresses can reduce the time taken to reach a solution; and it enables the effects of larger reels, higher speeds and new materials to be considered with a degree of certainty. This significantly reduces the risk of building equipment or running a new product on production scale. To appreciate the theory fully, graduate-level engineering mathematics is needed. However, there are sufficient explanations and figures for this section to be comprehensible and valuable for readers without that background.
To perform the modelling, the book comes with “WindARoll” software written using Microsoft Excel® as a platform. This calculates and plots graphs of roll stresses, wound-on tension (after passing through the contact nip), torque capacity and limiting speeds for significant air entrainment and telescoping. A useful library of web material properties can be called up. Each input has a clear pop-up help comment of what is required and its significance.
The book is unique in the way it applies recent academic research to solving practical winding problems. It represents a significant advance on Roisum’s earlier book, “The Mechanics of Winding”, published in 1994. It will continue to be useful as rolls of basic papers and films are produced at higher speed and larger sizes, and novel materials such as flexible electronics, medical products and laminates are found in roll form at some stage during their manufacture.
By Dilwyn P Jones, Consultant, Emral Ltd, UK
James K Good and David R Roisum
TAPPI Press and DEStech Publications Inc 2007. 398pp
There is a pervasive myth in our industry that tough problems can only be solved by Joe, the one guy on the line who knows which magic knob to tweak to get things to work. The myth is especially popular with Joe himself as he thinks it helps keep him in his job – which it does till the magic fails one more time and the whole company goes bust. There may once have been an excuse for the Joes of this world. But gradually the science of what we are all doing has become clearer and scientific ways of solving problems have become more practical. And now for those of us who have winding problems (and that’s just about everyone who handles a web) the excuses have finally disappeared. This extraordinary book does three things at the same time. First, it gives simple “recipes” for fixing problems and explains them with exceptional clarity and insight. Second, it gives the deep technical background as to why these recipes work. Third, through the use of case studies we can all recognise it shows how the theory and practice come together and therefore why, unlike Joe’s magic, the recipes work.
As the title suggests it also breaks the subject down in another three-way manner. First, it steers you through the different types of winding machines with their varying degrees of complications and sophistication. One particularly engaging aspect of this is that it emphasises how sophistication might be necessary to solve your problems, but reminds why extra sophistication can sometimes make life worse. Using their terminology, a “three-knob” winder may not always be better than a “one-knob” winder. Second, it gives an authoritative review of the mechanics of what’s happening as the roll winds and why certain conditions can guarantee problems. Third, whilst admitting that many of the measurement techniques on wound rolls are less than perfect, it shows how to get the best out of the techniques and why you should go to the trouble.
What sorts of problems does it help you solve? Telescoping, starring, tin-canning, bursts, crepe wrinkles, core collapse, high-speed vibrations, gauge bands. These are just some of the defects they discuss. One of the problems in our industry is that we all have different names for our defects. The authors give each problem a precise name, but provide the readers with plenty of alternative names so you can quickly work out when they are discussing defects that apply to your shop.
A book written by a professor and a consultant could be a mixture of impenetrable academic prose and frothy consultant speak. But Good and Roisum make sure that you get the best of both worlds –insightful science coupled with hard-nosed reality from the shop floor. The book is a delight to read because even when you are out of your comfort zone, the two authors are convincing you that you really do want to understand this particular topic because it will help you solve a problem that’s bugged you for years.
This is an expensive book. Can you really justify the cost of buying it? Well, I can speak from my experience. My copy arrived just as a major winding issue arose at our facility across the Atlantic. I was asked to lead the team to solve the issue – rather hard when you’re 3500 miles away. Although I consider myself pretty comfortable with many aspects of winding theory and had my own computer models, I didn’t have any confidence in my instant diagnosis of the root cause. But the book quickly gave me the key insights I required to become convinced that I understood the root cause. Because the cure would have some downsides (don’t they always – and the book explains why!) I had to convince a sceptical management that it was the right way to go. The book gave me the sorts of clear arguments that go down well with management, including a picture of a problem roll that looked identical to our own. I would be very surprised if the book didn’t pay for itself quickly in your own business unless, that is, you are one of the rare few who happen to have no problems winding rolls.
For such a complex book there are remarkably few errors. A missing minus sign from one equation caused me some problems but that was a very rare glitch. The delicate matter of units is handled well. The default is, thankfully, metric units, but US units (I have a problem calling them British units) are always provided so that US readers will remain comfortable throughout the book.
There’s a bonus. The book includes a CD with a powerful winding modeller. This means that you can put in your own winding parameters and see what’s going on inside your own rolls – taking into account taper, nip pressure, air entrainment and thermal/hygroscopic effects. Although it’s a great modeller (and has been verified by many lab experiments) you have to invest some modest effort into getting some key parameters such as web roughness and radial modulus before you can get a lot out of it. But then life’s like that – the more you put in, the more you get out.
Why have Good and Roisum produced this amazing book? As they admit, it’s not for the money. And as they are both famous in the industry it’s not to raise their profiles. Their reason is that they share a passion for applying science and engineering to solving real production problems. It’s fashionable to blame the woes of industry on, for example, cheap competition. But many of our woes come from our inability to engage brain and solve problems. We let the Joes of this world run our companies for us, with disastrous results. This book is a an antidote to Joe. And who knows, you might even persuade Joe to learn from it. Then you all keep your jobs.
In three words: buy this book!
Professor Steven Abbott
Research & Technical Director