Microstructured Metal Mold Insert for Low-Distortion Lens Molding
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Solution Overview
Problem
Glass inserts used in injection molding for lenses with microstructures are difficult to produce, prone to breakage, and result in high equipment downtime, leading to reduced productivity and increased defects like weld lines and center distortions.
Innovation Solution
A mold insert comprising a functional surface made of a nickel alloy with a bulk portion of stainless steel, plated with NiP, which is diamond turned to create microstructures, providing durability and low thermal conductivity to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass inserts with low thermal conductivity are used, then weld line and center distortion defects are reduced, but microstructure fabrication becomes difficult and expensive
Solution Approach 1:
The patent changes the material parameter from glass to metal alloy with specifically controlled thermal conductivity (1-50 W/m-K) and modulus (100-1000 GPa) ranges, enabling both low thermal conductivity for defect prevention and high durability for microstructure fabrication
Solution Approach 2:
The patent uses composite construction with a bulk metal alloy body coated with a functional surface layer (first metal alloy) that has different properties optimized for microstructure fabrication, while the bulk material provides the required thermal behavior
2Reliability
If glass inserts are used, then thermal conductivity is low and defects are prevented, but the inserts break easily during molding causing equipment downtime
Solution Approach 1:
The patent changes the material from glass to metal alloy, fundamentally altering the strength and durability parameters while controlling thermal conductivity through material selection and composition
Solution Approach 2:
The patent creates a durable metal alloy insert that can withstand the molding process without breaking, eliminating the need for frequent replacements and reducing equipment downtime associated with fragile glass inserts
3Temperature
If glass inserts with microstructures are produced, then thermal behavior is appropriate, but the microstructures are easily broken during handling and cleaning
Solution Approach 1:
The patent uses a composite structure where the bulk metal alloy provides thermal properties and structural strength, while the functional surface coating provides the microstructures with enhanced durability against breakage during handling and cleaning operations
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 NiP plated stainless steel mold insert reduces weld line and center distortion defects, enhances durability, and improves production efficiency by reducing cycle time and maintaining optical quality.
Implementation Method 1
the metal alloy has a thermal conductivity between 1 and 50 W/m-K
Implementation Method 2
coating a bulk portion of the mold insert with a first metal alloy
Data Source
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AI summary
A mold insert includes a plurality of microstructures along a surface of the mold insert and a metal alloy, wherein the metal alloy has a thermal conductivity between 1 and 50 W/m-K, and wherein the metal alloy has a modulus of between 100 GPa and 1000 GPa.