Rippled Papermaking Fabric for Tissue Bulk and Runnability

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Solution Overview

Problem

Current papermaking fabrics face challenges in improving tissue bulk, machine runnability, and reducing pinholes, while maintaining fiber support and fabric robustness, particularly in through-air drying and creping processes.

Innovation Solution

Development of narrow wale papermaking fabrics with a textured surface featuring substantially continuous machine-direction ripples supported by multiple shute strands, which enhance fabric stiffness, tissue bulk, and fiber support, and are suitable for both through-air drying and wet-pressed processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional papermaking fabrics are used, then machine runnability is maintained, but tissue bulk and fabric stiffness are insufficient

Engineering Contradiction:

Improvefabric stiffnessVSAvoidmachine runnability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The fabric is segmented into multiple functional layers: a base fabric layer for machine runnability and a topographical layer with ripples and valleys for tissue bulk enhancement. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fabric combines different material properties in a composite structure, integrating the stability of traditional fabrics with the bulk-enhancing properties of topographical features. The composite construction achieves both improved stiffness and maintained runnability.

Inventive Principle:

Principle #40Composite materials

2Volume of stationary object

If fabric topography is enhanced for improved molding, then tissue bulk increases, but pinholes increase

Engineering Contradiction:

Improvetissue bulkVSAvoidpinholes

Core Design Contradiction:

Volume of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The fabric features localized topographical variations with specific ripple amplitudes and valley depths optimized for molding, while maintaining uniform areas for fiber support. This local quality differentiation enhances bulk in specific zones without creating pinholes in others.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fabric parameters such as ripple wavelength, amplitude, and valley depth are precisely controlled within specific ranges to optimize the balance between tissue bulk enhancement and pinhole prevention. Parameter optimization ensures adequate fiber support while achieving desired bulk.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If fabric topography is modified for better tissue structure, then molding characteristics improve, but fabric robustness decreases

Engineering Contradiction:

Improvemolding characteristicsVSAvoidfabric robustness

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The topographical features are pre-formed into the fabric structure during manufacturing, creating permanent ripples and valleys that provide consistent molding characteristics. This preliminary action ensures robustness is maintained while achieving precise molding control.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7611607B2Rippled papermaking fabrics for creped and uncreped tissue manufacturing processes

Publication Date: 2009.11.03 VOITH PATENT GMBH

AI summary

A woven fabric for a papermaking machine includes a textured sheet contacting surface having substantially continuous machine-direction ripples separated by valleys. The ripples are formed of multiple warp strands grouped together and supported by multiple shute strands of two or more diameters.