Differential Speed Perforation Nip for Complex Tissue Patterns
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Solution Overview
Problem
Existing tissue converting equipment for making perforated tissue products has limitations in flexibility and maintenance due to high-speed impact requirements, resulting in short blade and anvil life and limited ability to create varied perforation patterns.
Innovation Solution
A low-impact perforation method using a rotating pattern roll with protruding elements and a moving anvil surface with differential speed to create complex perforation patterns, allowing for increased flexibility and reduced wear on equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional high-speed impact perforation is used, then perforation speed is high, but blade and anvil life is short and maintenance frequency increases
Solution Approach 1:
The patent changes the fundamental operating parameters of the perforation system by reducing the relative speed between the blade and anvil from high-speed impact to low-speed differential motion. The blade and anvil move at different speeds creating continuous contact rather than intermittent impact, which transforms the stress regime from high-impact cyclic loading to continuous low-stress shearing, thereby extending component life while maintaining productivity
Solution Approach 2:
The patent introduces dynamic motion to both the blade and anvil surfaces, where they move at different speeds rather than one being stationary. This dynamic configuration creates a continuously varying contact point that distributes wear across larger surface areas and reduces stress concentration, resolving the contradiction between maintaining high productivity and extending component life
2Ease of operation
If conventional straight perforation lines are used, then the system is simple to operate, but flexibility in perforation patterns is limited
Solution Approach 1:
The patent employs dynamic motion of the blade and anvil at different speeds to create variable perforation patterns. By adjusting the speed differential and motion characteristics, the system can produce straight lines, curves, and complex geometric patterns without changing the physical configuration of the components, thus maintaining operational simplicity while achieving high pattern flexibility
Solution Approach 2:
The patent creates a universal perforation system where the same blade-anvil configuration can produce multiple types of perforation patterns (straight, curved, geometric) by varying operational parameters rather than requiring different physical tools or configurations, thereby achieving versatility without compromising ease of operation
3Productivity
If high-speed impact perforation is used, then perforations are created efficiently, but vibration increases requiring skewed blades and accurate setup
Solution Approach 1:
The patent changes the speed parameter from high-impact to low-speed differential motion, which fundamentally alters the vibration characteristics. The continuous low-speed shearing action eliminates the high-frequency vibrations associated with impact perforation, removing the need for skewed blades and complex vibration control mechanisms while maintaining perforation efficiency
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
Enables the creation of complex and visually distinct perforation patterns at commercial speeds, improving sheet detachment and product differentiation while extending equipment lifespan.
Implementation Method 1
the web and the surface of the rotating pattern roll moving at the same speed; and (b) passing the web through nips formed between the protruding perforation elements and a moving anvil surface, such as a rotating anvil roll or a traveling belt, the surface of which is traveling at a speed that is different than the speed of the web
Implementation Method 2
whereby the web is locally sheared and perforated in the nips to create a perforation pattern in the sheet
Data Source
AI summary
Curvilinear or other complex perforation patterns for paper products, such as paper towels and bath tissue, can be produced using a differential speed perforation nip formed between a rotating pattern roll and a moving anvil surface. The relative speed between the perforation elements on the surface of the pattern roll and the anvil surface shears the web at the perforation points.