TJWA WH0 Intro Overview

7/31/2019 TJWA WH0 Intro Overview

1/18


2/18

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

TJWA Inc., Copyright 2012 www.webhandling.com 2


3/18

Web Handling Processes

Makers:Coating, Extrusion, & Paper and

Film-Making

Converters: Slitting,Die-Cutting, &

Laminating

Controls!

Critical to successful webhandling.



4/18



5/18

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.



6/18

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.



7/18

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.



8/18

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?



9/18

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?



10/18

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



11/18

Part 2: Solutions with Imperfect Webs

BaggyWebs

CamberedWebs

Cambered and Baggy Webs

CurledWebs

Non-Flat Webs



12/18

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



13/18

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



14/18

Crossweb Tension

Variations

Four Basic Principles of Webs

Stress and Strain

Parallel Entry Rule

Shape Stiffness



15/18

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)



16/18

Spans: End Tensioning

Tensioning from Rollers: Runout,

Straightness,

Eccentricity,

Level, Tram

Web path length variations

Stretch (strain) variations

Tension (stress) variations



17/18

Diameter variations

Speed variations

Stretch (strain) variations

Tension (stress) variations

Rollers: Straining to Conform

The web stretches, attemptingto conform to the rollers shape.



18/18

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.


TJWA WH0 Intro Overview

Documents