Injection molded screening apparatuses and methods
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Solution Overview
Problem
Conventional screens for vibratory screening machines, whether made of metal or thermoset polymer, face issues such as complex fabrication, high cure times, structural instability, rapid blinding, and limited configurational flexibility, leading to inefficiencies and high costs.
Innovation Solution
Injection molded thermoplastic screen elements are used, which can be easily assembled into larger assemblies through welding, allowing for versatile configurations and enhanced durability, with reinforcement fibers embedded to withstand tensioning forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermoset polymer screens are fabricated using traditional liquid mixing and molding methods, then screens can be produced with fine openings, but the cure time is extremely long (10 hours or more) and production rate is very low
Solution Approach 1:
The patent changes the fundamental material parameter from thermoset polymer to thermoplastic material. This parameter change enables the use of injection molding technology, which reduces production time from 10+ hours to minutes while maintaining the capability to produce fine opening screens through precise mold design and material flow control.
Solution Approach 2:
The patent replaces the chemical curing process (thermoset polymerization) with a mechanical injection molding process. Instead of relying on chemical reactions that take 10+ hours to cure, the thermoplastic material is injected into the mold, cooled, and ejected in minutes, dramatically increasing production rate while maintaining manufacturing precision.
2Area of stationary object
If screen surface elements are made very fine (40-100 microns) to achieve large open screening area, then screening efficiency improves, but fabrication becomes extremely difficult and time consuming
Solution Approach 1:
The patent uses a precision mold as a template or copy of the desired screen pattern. The mold contains the exact geometry of fine screen surface elements (40-100 microns) and reproduces this pattern repeatedly through injection molding. This copying approach makes fabrication easy and consistent, eliminating the difficulty of manually creating such fine features.
Solution Approach 2:
The patent changes from manual or complex fabrication methods to injection molding with thermoplastic material. This parameter change enables precise control of screen surface element dimensions (40-100 microns) through mold design, making it easy to manufacture screens with large open screening area without the fabrication difficulties associated with traditional methods.
3Productivity
If thermoset screens are made in large sizes to avoid assembly time, then production rate improves, but any single flaw (hole, rip, tear) ruins the entire screen
Solution Approach 1:
The patent produces screens in modular segments or complete large screens through injection molding. The thermoplastic material's properties and the molding process allow for production of large screens without the fragility issues of thermoset materials. Any defects are less likely to ruin the entire screen due to the material's toughness and the controlled molding process, maintaining both high production rate and reliability.
Solution Approach 2:
The patent changes from thermoset to thermoplastic material, which fundamentally alters the reliability parameter. Thermoplastic materials are more tolerant of defects and can be repaired or reprocessed, whereas thermoset materials become brittle and fail catastrophically. This parameter change allows large screens to be produced at high rates while maintaining integrity, as defects do not automatically ruin the entire screen.
4Adaptability or versatility
If conventional thermoset screens are used, then screens can be made with specific configurations, but fabrication is complicated and prone to errors
Solution Approach 1:
The patent uses a universal injection molding process that can produce various screen configurations (different opening sizes, patterns, and geometries) by changing the mold design rather than the fundamental manufacturing process. This universal approach simplifies fabrication while maintaining adaptability to different screening requirements, eliminating the complexity associated with traditional thermoset fabrication methods.
Solution Approach 2:
The patent changes from thermoset polymerization to thermoplastic injection molding, which fundamentally simplifies the fabrication process. The injection molding process is more controllable, faster, and less prone to errors than traditional thermoset methods, while still allowing for versatile screen configurations through mold design. This parameter change resolves the contradiction between adaptability and ease of manufacture.
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 provides screen assemblies with high open screening area, resistance to blinding, extended lifespan, and improved structural stability under heavy loads, reducing fabrication time and costs while maintaining performance.
Implementation Method 1
Injection molded screen elements are formed from a thermoplastic material
Implementation Method 2
Injected molded screen elements are formed from a thermoplastic material
Implementation Method 3
can be easily assembled into larger assemblies through welding
Data Source
AI summary
A screen assembly is formed by attaching side edges of a plurality of screen elements to each other. Reinforcing fibers may be embedded in the material of selected screen elements. The reinforcing fibers extend in a direction in which the screen assembly will be tensioned to secure the screen assembly to a screening machine. Hook strips may be attached to ends or sides of the screen assembly to facilitate mounting the screen assembly to a screening machine.