Extrusion Die Shim Segmentation for Polymeric Netting Bonding
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Solution Overview
Problem
Current extrusion processes for polymeric nets are limited in producing nets with specific compositional arrangements and characteristics, such as thin strands and small mesh sizes, and often require complex dies with moving parts, which restricts their versatility and application range.
Innovation Solution
The development of an extrusion die with a unique shim configuration that allows for the simultaneous dispensing of polymeric strands at different speeds, creating a netting with periodically joined strands and varying material compositions on its surfaces, enabling the production of nets with tailored properties like elastic bandages, filtration, and geotextiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If complex dies with moving parts are used in extrusion processes, then netting production is enabled, but device complexity increases and versatility is restricted
Solution Approach 1:
The die is divided into multiple independent shim layers, each contributing to the formation of specific strands. This segmentation allows complex netting patterns to be achieved through simple stacked components rather than a single complex die with moving parts.
Solution Approach 2:
Multiple shim layers are nested within each other to form the complete die structure. Each shim is inserted into recesses of adjacent shims, creating a compact assembly that produces multi-material strands through the nested configuration of material passageways.
2Ease of manufacture
If conventional extrusion processes are used, then netting can be produced, but compositional arrangement versatility is limited
Solution Approach 1:
Different regions of the die (different shim layers and material passageways) are assigned different polymeric materials with specific properties. This allows local customization of strand composition, enabling diverse netting applications such as elastic bandages, filtration, and geotextiles from a single die structure.
Solution Approach 2:
The die is designed to simultaneously extrude multiple polymeric materials that form composite strands. These composite materials combine different properties (e.g., elasticity, strength, filtration characteristics) within single strands, expanding the versatility of producible netting.
3Ease of manufacture
If films are slit and expanded to produce netting, then netting is obtained, but mesh size is relatively large and cross-point strength is weak
Solution Approach 1:
The die structure pre-forms strands with integrated bonding capabilities before extrusion. The bonding regions are designed into the die geometry itself, ensuring strong cross-points are created during the extrusion process rather than requiring subsequent processing of large-mesh slit films.
4Adaptability or versatility
If multiple polymeric materials are extruded through a single die, then compositional variety is achieved, but material mixing occurs which compromises material properties
Solution Approach 1:
The die is segmented into separate shim layers with dedicated material passageways for each polymeric material. This segmentation prevents unwanted mixing while allowing precise control over where different materials are deposited to form layered or composite strand structures.
Solution Approach 2:
The shim structure acts as an intermediary that guides and separates different polymeric materials through distinct passageways. The shims with recesses and protrusions create defined flow paths that maintain material separation until the intended bonding regions where controlled interaction occurs.
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 method enables the production of netting with controlled strand bonding and material distribution, enhancing its strength, elasticity, and application range across various uses, including medical, filtration, and geotextile applications, while simplifying the die design and process complexity.
Implementation Method 1
an extrusion die having at least first and second cavities, a first passageway extending from the first cavity into a first vestibule defining a first dispensing orifice, and a second passageway extending from the second cavity to the vestibule
Data Source
AI summary
Netting (100) comprising an array of polymeric strands (121, 122) periodically joined together at bond regions (113) throughout the array, and methods and dies for making the same. Nettings described herein have a variety of uses, including wound care and other medical applications, filtration, absorbent articles, pest control articles, and geotextile applications.