Reaction Cell Thickness Gradient Prevents Welding in Biochemical Analyzer
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Solution Overview
Problem
Molding failures, particularly weld generation, in reaction cells for automatic biochemical analyzers lead to light scattering and measurement errors, resulting in defective products and reduced yield, especially in serial cell manufacturing where a single failure affects the entire integrated unit.
Innovation Solution
The reaction cell design features specific thickness relationships between flat plates and corner portions to prevent resin merging and weld formation in beam transmission parts, achieved by optimizing the size and shape of the mold cavity to ensure uniform resin flow and air exhaustion, thereby minimizing the merging angle and flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection molding is used to manufacture reaction cells for high productivity, then manufacturing efficiency is improved, but weld generation occurs in beam transmission parts causing light scattering and measurement errors
Solution Approach 1:
The patent applies local quality by making the corner portions thinner than the beam transmission parts. This creates a thickness distribution where the beam transmission parts maintain uniform, sufficient thickness to prevent weld generation and ensure optical quality, while corner portions are intentionally made thinner to control resin flow patterns during injection molding, preventing welds in critical beam transmission areas.
Solution Approach 2:
The patent changes the thickness parameter distribution within the reaction cell structure. By setting corner portion thickness to be less than beam transmission part thickness, the resin flow dynamics are altered during molding, directing flow away from beam transmission areas and preventing weld formation in these critical regions while maintaining manufacturing efficiency.
2Productivity
If serial cells are integrally molded to enhance productivity and reduce cost, then production efficiency is improved, but a single molding failure affects the entire integrated unit resulting in complete loss
Solution Approach 1:
The patent applies local quality by creating thinner corner portions that serve as resin flow control zones. This local thickness variation prevents weld generation in the beam transmission parts of all cells within the serial structure, ensuring that molding failures do not propagate across the entire integrated unit and maintaining reliability while preserving high productivity benefits.
3Device complexity
If uniform thickness is used throughout the reaction cell for simplicity, then manufacturing complexity is reduced, but weld generation occurs in beam transmission parts due to improper resin flow control
Solution Approach 1:
The patent deliberately introduces local thickness variation by making corner portions thinner than beam transmission parts. This controlled non-uniformity serves to manage resin flow patterns during injection molding, preventing weld generation in beam transmission areas while adding minimal structural complexity and maintaining manufacturing feasibility.
Solution Approach 2:
The patent addresses the two-dimensional uniform thickness problem by introducing a third dimension consideration - the vertical thickness variation at corner portions versus beam transmission areas. This dimensional approach to thickness control enables proper resin flow management and weld prevention while maintaining overall structural simplicity.
Data Source
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Figure 3(a)~3(b)
AI summary
A reaction cell for automatic biochemical analyzer in which weld generation in beam transmission parts is prevented to reduce scattering of transmitted beam, thereby having a stable transmissivity to achieve high analytical efficiency is provided. It is a reaction cell which is bottomed and has an opening formed on one end, the reaction cell comprising a tube wall including one pair of walls facing to each other and two side walls each connecting to each of the one pair of walls via a corner portion, wherein the one pair of walls each have a thickness larger than thicknesses of the corner portions, and have a uniform thickness over the entire wall, or when each wall has a maximum value in thickness in a part of the wall, the thickness monotonically decreases from the part having the maximum value to the corner portion.