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7/31/2019 TJWA WH0 Intro Overview
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What is Web Handling?
The process technology of transporting and storing thin,flexible materials.
A web is any flexible, continuous material where:
Length >> Width >> Thickness Webs include papers, films, foils,
non-wovens, textiles, and laminates.
Th
ickness Width Length
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Web Handling Processes
Makers:Coating, Extrusion, & Paper and
Film-Making
Converters: Slitting,Die-Cutting, &
Laminating
Controls!
Critical to successful webhandling.
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Tension ControlBased on
Material and Process
Requirements
Part 1
+ Web Properties
Know your webs mechanical and frictional properties.+ Tension Control
Understand what controls tension in your process.
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Part 2
Web Support:Rollers and Air Flotation
+ Roller Design
Design rollers for driving, idling, and nipping applications
Why is roller parallelism important?
+ Traction
Understand when webs slip on rollers.
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Part 3
Nipped Rollers Systemsand Lamination
+ Roller Design
Design rollers for driving, idling, and nipping applications
Why is roller parallelism important?
+ Traction
Understand when webs slip on rollers.
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Lateral Control ofGuiding, Wrinkling,
& Spreading Processes
Day 2, AM
Part 4
+ Web GuidingWhat cause a web to shift laterally?
What web guide is best for a process?
+ Wrinkling
What causes web wrinkles? What eliminates wrinkles?
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Part 5
WindingProcess Understanding
and Improvement
Day 2, PM
+ WindersWhat winder design is best for a product?
+ Winding and Roll Structure
What determines the pressure inside a wound roll?
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Part 1: Solutions w/ Web Tensioning
MachineDirection
Tension:MD Variations
Tension:Too High or
Too Low
Tension:TD Variations
TransverseDirection
TD =
MD =
Tension:Varies Over
Time
Tension:Slit Strands
1A 1B 1E
1D
1C
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Part 2: Solutions with Imperfect Webs
BaggyWebs
CamberedWebs
Cambered and Baggy Webs
CurledWebs
Non-Flat Webs
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Part 3: Solutions with Slipping/Shifting Webs
MD Slipon Rollers
3A: MD Slip Between Web andDriven or Idler Rollers
MD Slipin Rolls
3B: MD Slip Between Layers
in a Rolls
TD Slip/Shifton Rollers
TD Errorin Rolls
3C: Web TD Shifts or SlipsLaterally on Rollers
3D: TD Shift or Misalignment
of Layers in a Rolls
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Part 4: Solutions with Buckled Webs
In Spans
Buckled
BetweenRollers
Buckled Web in
Spans
MD BucklesOn Rollers
TD Buckles
On Rollers
On Rollers In Rolls
MD BucklesRolls
TD Buckles
in Rolls
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Crossweb Tension
Variations
Four Basic Principles of Webs
Stress and Strain
Parallel Entry Rule
Shape Stiffness
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What Does the Web Feel?
1. Spans:End Tensioning
2. Rollers:
Straining to Conform
3. Nips:Under Pressure
4. Other External Forces (air flow, coatings)
5. Internal Forces (length variations, shrinkage,viscoelastic recovery)
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Spans: End Tensioning
Tensioning from Rollers: Runout,
Straightness,
Eccentricity,
Level, Tram
Web path length variations
Stretch (strain) variations
Tension (stress) variations
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Diameter variations
Speed variations
Stretch (strain) variations
Tension (stress) variations
Rollers: Straining to Conform
The web stretches, attemptingto conform to the rollers shape.
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Diameter variations
Alignment variations
Loading variations Hardness variations
Deflection variations
Product thickness variations
Nips: Under Pressure
Nips create the highest pressureson the web.
Nips variations can create BIG
pressure variations.
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