Dual Slip Cut Unit for Zero Waste Diaper Ear Application
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Solution Overview
Problem
Current diaper manufacturing processes result in significant waste due to the inefficiencies in processing and recycling of raw materials, particularly in the application of discrete web segments, where recyclable materials are often commingled and require additional steps for separation, leading to material wastage.
Innovation Solution
A dual slip cut unit and apparatus that allows for the precise cutting and orientation of trapezoidal ear webs with zero or minimized waste, using a rotary knife or die in coordination with a cylinder to create trapezoidal ears, which are then rotated and applied to a chassis web using an ear turner assembly, enabling efficient attachment with minimal material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional slip-and-cut applicators are used to apply discrete web segments, then diaper production can proceed, but significant material waste occurs due to inefficiencies in processing and recycling
Solution Approach 1:
The incoming web is divided into multiple lanes (e.g., four lanes) before die cutting, allowing each lane to be processed independently. This segmentation enables more efficient material utilization by reducing gaps and waste between individual ear pieces while maintaining high-speed production capabilities
Solution Approach 2:
The web is pre-slit into multiple lanes before the die cutting operation. This preliminary action optimizes the subsequent cutting process by allowing the die to cut nested patterns across multiple lanes simultaneously, maximizing material utilization and eliminating waste that would occur with traditional single-piece cutting methods
2Loss of substance
If recyclable materials are harvested from defective products at the end of the process, then waste can be recycled, but the materials become commingled and require additional separation steps
Solution Approach 1:
The patent converts potential waste material into useful product by using a nested die cutting pattern that leaves no gaps between ears. The previously wasted material between individual ear pieces is now utilized to create additional ears, transforming what would have been waste into valuable recyclable material that maintains its purity and does not require complex separation processes
3Loss of substance
If ear pieces are die cut with nested patterns, then zero material waste is achieved, but the ears must be rotated into correct orientation
Solution Approach 1:
The die cutting pattern creates asymmetric nested arrangements where ears in alternating positions are oriented differently. This asymmetric nesting allows the web to be cut with zero waste while creating a predictable pattern of orientations that can be systematically corrected through rotation of specific lanes or individual pieces
4Productivity
If operational speeds of diaper converters are increased, then productivity improves, but the mechanical integrity and operational capabilities of applicators must be improved accordingly
Solution Approach 1:
The applicator system is segmented into multiple independent lanes that process web material in parallel. This segmentation allows each lane to operate at high speed while the overall system maintains mechanical integrity through distributed loading, preventing the stress concentration that would occur in a single high-speed cutting operation
Solution Approach 2:
The web is pre-slit into multiple lanes before reaching the die cutting station. This preliminary action distributes the mechanical stress of high-speed cutting across multiple smaller, more manageable cutting operations, allowing the system to maintain high operational speeds without compromising the mechanical integrity of the applicator components
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
The solution achieves zero material waste by optimizing the geometry of ear patterns and downstream processing, ensuring correct orientation of ear pieces and reducing the need for additional steps in material handling, thereby enhancing operational efficiency and reducing waste in diaper production.
Implementation Method 1
A dual slip cut unit and apparatus that allows for the precise cutting and orientation of trapezoidal ear webs
Implementation Method 2
an incoming web is fed at a relatively low speed along the vacuum face of the rotating anvil
Implementation Method 3
which are then rotated and applied to a chassis web using an ear turner assembly
Implementation Method 4
a dual intermittent ultrasonic bonding anvil roll
Data Source
Figure 1~3
Figure 4~5A
Figure 6~7B
AI summary
The present invention provides a dual slip cut unit (2100). The dual slip cut unit comprises: a rotating anvil (2106); a first rotating knife (2104) engageable with the rotating anvil (2106) to cut a plurality of severed pieces (2102') from an extension panel web (2102); a second rotating knife (2104) engageable with the rotating anvil (2106) to cut each severed piece (2102') into first and second subdivided pieces (2102''); and a transfer drum (2108) configured to receive the first and second subdivided pieces (2102'') from the rotating anvil (2106). The rotating speed of the rotating anvil (2106) creates a first gap between adjacent severed pieces (2102') and the rotating speed of the transfer drum (2108) creates a second gap between adjacent first and second subdivided pieces (2102'').