Injection Molded Thermoplastic Screen Assembly for Vibratory Screening
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Solution Overview
Problem
Conventional screening assemblies for vibratory screening machines face issues such as lack of structural stability and durability, blinding of screening openings, high fabrication complexity, and limited configuration options, particularly with thermoset polymer and metal screens, which affect their performance and longevity in various industrial applications.
Innovation Solution
The use of injection molded thermoplastic screen elements attached to subgrid structures, which are securely fastened together to form a screen assembly with improved mechanical and chemical properties, allowing for customizable configurations, precise fabrication of small openings, and enhanced durability under vibratory loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermoset polymer screens are used for fine screening applications, then screening precision is improved, but fabrication complexity and time increase significantly
Solution Approach 1:
The patent changes the material parameter from thermoset polymer to thermoplastic polymer, which fundamentally alters the fabrication process. Thermoplastics can be injection molded directly into fine screening patterns without requiring complex multi-step curing processes, chemical reactions, or precise temperature/pressure control during fabrication. This parameter change enables precise fine screening openings to be achieved through standard injection molding techniques, dramatically reducing fabrication complexity and time while maintaining manufacturing precision.
2Reliability
If thermoset polymer screens are tensioned to secure them to the machine, then attachment reliability is improved, but structural stability deteriorates due to buckling under compression
Solution Approach 1:
The patent changes the material parameter from thermoset polymer to thermoplastic polymer, which fundamentally alters the mechanical behavior under load. Thermoplastics exhibit different stress-strain characteristics and can be engineered to withstand both tension and compression forces. This enables the screen to be securely attached through compression forces without buckling, maintaining structural stability while achieving reliable attachment, eliminating the need for tensioning members that cause deformation.
3Reliability
If metal screens are used for durability in wet applications, then durability is improved, but weight increases and fabrication complexity increases
Solution Approach 1:
The patent employs thermoplastic polymer materials that offer a composite-like performance profile, combining the durability and chemical resistance needed for wet applications with the lightweight characteristics of polymers. These engineered thermoplastics can be formulated to withstand harsh chemical environments and mechanical wear while maintaining significantly lower density than metal screens, thus reducing weight without sacrificing durability in wet industrial applications.
4Reliability
If metal screens are used for durability, then durability is improved, but fabrication complexity increases due to multiple components and assembly steps
Solution Approach 1:
The patent merges multiple separate metal components (screening material, backing plate, bonding layers) into a single integrated thermoplastic polymer structure. The thermoplastic screen can be injection molded as one piece with built-in structural features, eliminating the need for separate backing plates and bonding operations. This consolidation maintains durability through the inherent strength of thermoplastic materials while dramatically simplifying fabrication by reducing the number of manufacturing steps and assembly operations required.
5Manufacturing precision
If conventional thermoset polymer screens are fabricated with small openings, then screening precision is improved, but the liquid does not reach all cavities in the mold, ruining the entire screen
Solution Approach 1:
The patent changes the material parameter from thermoset polymer to thermoplastic polymer, which fundamentally alters the molding process behavior. Thermoplastics have different viscosity characteristics and flow properties that enable complete mold cavity filling even with very small feature sizes. The injection molding process for thermoplastics allows the material to flow into and completely fill all cavities, including those with fine screening openings, ensuring consistent production success and high fabrication yield without the defects associated with thermoset molding of fine features.
Data Source
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AI summary
A screen assembly and a method for fabricating a screen assembly are provided. The screen assembly comprises a screen element (16) including a screen element screening surface (13) having screening openings (86) is provided. The screen assembly further comprises a screen assembly support structure comprising a subgrid including a grid framework having grid openings (50). The screen element (16) spans the grid openings (50) and is attached to a surface of the subgrid. The screen assembly has a continuous screen assembly screening surface comprised of multiple screen element screening surfaces (13). The screen element (16) is an injection molded piece.