Web Perforation Roll Design for Flexible Pattern Changeover

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Solution Overview

Problem

Conventional perforation methods for web products like paper towels and bath tissue face issues with reliability, manufacturing costs, flexibility, and perforation quality due to vibrations and blade dullness, leading to web breaks and increased downtime for changing perforation patterns.

Innovation Solution

A perforating apparatus using a rotatable male roll with perforating elements and a rotatable female roll with pockets, allowing for controlled web overstraining without contact, enabling the creation of various perforation patterns and designs, including linear and nonlinear patterns, that complement embossed or printed patterns, while reducing downtime and waste.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a moving blade and stationary anvil are used to perforate the web, then perforation can be achieved, but vibrations are produced that adversely affect perforation quality and cause web breaks at high speeds

Engineering Contradiction:

Improveperforation qualityVSAvoidvibrations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of using a moving blade against a stationary anvil, the invention uses two rotatable rolls that rotate in the same direction at the same speed. The perforating elements on one roll engage with corresponding pockets on the other roll, inverting the traditional stationary-anvil approach to eliminate vibrations and web breaks caused by blade-anvil interaction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the mechanical blade-anvil system with a roll-to-roll engagement system. The perforating elements are pressed into the web by the rotational motion and engagement force between the two rolls, substituting the high-impact mechanical cutting action with a controlled rolling compression action that eliminates harmful vibrations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a moving blade is used to perforate the web, then perforation is achieved, but the blade teeth become dull or broken after a period of use, requiring shutdown and replacement

Engineering Contradiction:

Improvecontinuous operationVSAvoidblade life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The invention uses perforating elements that are pressed into the web and then released, avoiding the cumulative wear and damage that causes blade teeth to become dull or broken. The roll-to-roll engagement system allows for continuous operation without blade replacement, as the perforating elements are not subjected to the same wear mechanisms as conventional moving blades.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If conventional equipment is used, then perforation is achieved, but there is inability to quickly change from one perforation pattern format to another without significant downtime

Engineering Contradiction:

Improveperforation pattern changeoverVSAvoidchangeover downtime

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The invention uses rotatable rolls that can be dynamically adjusted to change perforation patterns. The perforating elements and corresponding pockets can be repositioned on the rolls to create different perforation formats, allowing quick changeover from one pattern to another without significant downtime or shutdowns.

Inventive Principle:

Principle #15Dynamics

4Strength

If conventional perforation methods are used, then sheets can be separated by tearing, but the perforations are not sufficiently strong to withstand winding while also not weak enough to facilitate easy separation

Engineering Contradiction:

Improveperforation strengthVSAvoidsheet separation

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The invention creates perforations with localized fiber disruption through the roll engagement process. The perforating elements press into the web and create controlled weakness points that are strong enough to withstand winding but weak enough to facilitate easy separation. The local quality of the perforation varies by location, with edge perforations being weaker to facilitate separation while maintaining overall web integrity.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enhances the reliability and quality of perforations, reduces manufacturing costs, and increases flexibility in producing web products with improved consumer desirability by allowing for efficient production of different perforation patterns without significant downtime.

Implementation Method 1

the web engaging edge of each of the perforating elements is spaced outwardly from an outer surface of the male roll for overstraining a web

Methodology Applied

Scientific EffectOverstraining: Deformation

Data Source

PatentUS8287977B2Uniquely perforated web product

Publication Date: 2012.10.16 PROCTER & GAMBLE CO

AI summary

Web products are disclosed which include forming selected perforation designs and patterns. The perforation designs and patterns can be formed in linear or nonlinear fashion, can extend in the cross direction or the machine direction and can be formed to complement or match an embossed or printed design on the web. The perforation designs and patterns can be formed utilizing various mechanical perforating techniques.