Adding & Preserving Quality - Finishing & Converting Balbir Singh & Carl Ingalls Tissue World Americas 2002

Changing Role of Converter Fluid & Semi- Fluid State Solid State P/M Dry End Wet End Paper Machine Converting Packaging Crepe Doctor Chemistry Chem. E. Mech. E. Solid Mech. Mech. E. Ind. E.

Finishing Processes Calendering Ply bonding or laminating Embossing Lotionizing Printing

Finishing in Converting The converter’s domain P/M Dry End Wet End Paper Machine “Converting” Packaging Crepe Doctor Practical location for finishing processes Alternate location for calendering

Why Calender? Handfeel Gain Bulk Reduction Bulk Leveling

Calender Nip Crowning Zero-Crown Nip-Control Skewing

Calender Gap Control Load activated For handfeel Against stops Bulk control

Handfeel Quality Curves Gain or loss, relative to the base paper. HF gain More calendering Before calendering Bulk loss More calendering Before calendering Actual values of product properties. Target HF HF Base paper HF Bulk

Finishing Is a Balancing Act Handfeel Bulk Calendering Bulk Strength Embossing Handfeel Absorbency Lotionizing

Process Control Curve – Embossing Base MDT Embossed Bulk Base CDT Embossed MDT Embossed CDT Base Bulk Operating range Nip Line Load (pli) No embossing (base sheet) More embossing

Quality Control Curve – Embossing Target Window Bulk range CDT range Bulk Base paper bulk & CDT (before embossing) CDT

Converter’s Needs Bulk b Stretch P P e F Strength F

Variability Uneven Bulk Tapered Reel Uneven Rolls Uneven strength Poor tracking Sheet breaks Holes & Nicks Sheet breaks Poor quality

Tissue World Americas 2002 Converting Workshop Reel Mechanics Tensile Stress Layer Pressure Reel Radius Reel Radius Bulk Nip Pli Reel Radius Reel Radius

Reel Types Secondary Arm Reel Linear Reel

Bulk: Thickness Under Pressure Embossing is not crushed. Embossing crushed, but not crepe. Bulk All 3 sheets crushed. Embossed Creped Flat Pressure

Product Properties How the user will experience the product. Bulk – fullness, thickness under pressure. Strength – resist failure during use. Absorbency – remove liquid. Handfeel – smoothness, cushion, drape. Ply count – implies quality. Visual appeal – implies quality.

Rewinders Two-Drum Horizontal Rail 2-Nips Weighting/Un-weighting Drum Speed Differential One-Nip One Speed Two-Drum Horizontal Rail

Tissue Winders Center Winder Surface Winder

Folder Transverse Fold Rollers Longitudinal Fold Plows

Combating Tools Bowed Roll Calender Rolls Dancer Rolls Draw Rolls

Grouping Combating Tools Nip Rolls Dancer 1. Unwind Stand Bow Roll Skew Roll Tension Roll Bow Roll 2. Embosser Stand Embosser Draw Rolls

A Diagnostic Tool Bulk CDT 0.50 Target Window 0.40 Bulk range 0.30 CDT range 0.20 0.10 Base paper bulk & CDT (before embossing) 50 100 150 200 250 CDT

Comparing Embossing Curves 0.50 0.40 Bulk range 0.30 Bulk CDT range 0.20 A C B 0.10 50 100 150 200 250 CDT

Specifying the Base Paper Window for Base Paper Properties Bulk range Bulk Window for Embossed Product Properties CDT range CDT

Conclusion Finishing Converting Finishing adds quality during converting. Focus on end-use properties. Manage tradeoffs between properties. Use Finishing Curves: - set base specs - centerline process - diagnose problems Converting Converting should start at crepe doctor. Make the reel uniform and soft. Avoid rewinding. Match equipment with the product. Provide necessary combating tools.