Injection Mold Temperature Control for Optical Lens Precision
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Solution Overview
Problem
Conventional injection molding techniques face challenges in producing long molded articles with precise optical surfaces, such as fθ lenses, due to uneven cooling rates and internal stresses that lead to sink marks and reduced precision.
Innovation Solution
An injection molding apparatus with a temperature adjusting circuit that differentiates the temperature of first and second surfaces within the mold cavity, allowing for controlled cooling and solidification rates to match the precision requirements of optical surfaces, using a combination of first and second temperature adjusting circuits to manage temperature gradients and reduce internal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform cooling is applied to the entire mold cavity, then the manufacturing process is simple, but sink marks occur and optical surface precision is reduced
Solution Approach 1:
The patent applies different temperature control strategies to different regions of the mold cavity. The first temperature adjusting circuit maintains higher temperatures near the optical surfaces (second surfaces) to prevent sink marks, while the second temperature adjusting circuit applies lower temperatures to other regions for efficient cooling. This localized temperature differentiation resolves the contradiction by improving optical surface precision without requiring a completely complex system, as it only modifies specific zones rather than the entire mold.
Solution Approach 2:
The temperature control system is segmented into multiple independent circuits: a first temperature adjusting circuit for regions requiring higher temperatures (near optical surfaces) and a second temperature adjusting circuit for regions requiring lower temperatures. This segmentation allows each circuit to be optimized independently, improving manufacturing precision while keeping individual circuit complexities manageable, thus resolving the contradiction between precision and overall system complexity.
2Productivity
If rapid cooling is applied to the mold cavity, then productivity increases, but internal stresses increase and precision is reduced
Solution Approach 1:
The patent implements localized cooling rates by using the first temperature adjusting circuit to maintain higher temperatures in regions adjacent to optical surfaces, preventing rapid cooling that would cause internal stresses and precision loss. Simultaneously, the second temperature adjusting circuit applies rapid cooling to other regions to maintain productivity. This spatial differentiation of cooling rates resolves the contradiction between productivity and precision.
3Manufacturing precision
If high temperature is maintained throughout the mold cavity, then optical surface precision is improved, but energy consumption increases and cooling efficiency decreases
Solution Approach 1:
The patent applies high temperature maintenance only locally near the optical surfaces (second surfaces) using the first temperature adjusting circuit, rather than throughout the entire mold cavity. This localized approach improves optical surface precision while minimizing energy consumption, as only specific zones require elevated temperatures. The rest of the mold is efficiently cooled by the second temperature adjusting circuit, resolving the contradiction between precision and energy use.
Solution Approach 2:
The mold temperature control is segmented into zones with different temperature requirements. The first temperature adjusting circuit serves regions needing high temperatures for precision, while the second temperature adjusting circuit serves regions optimized for cooling efficiency. This segmentation reduces overall energy consumption compared to uniform high-temperature maintenance, while still achieving the required optical surface precision.
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 effectively suppresses sink marks and reduces internal stresses in molded articles, ensuring higher precision and consistent quality of optical surfaces by optimizing the cooling and solidification process.
Implementation Method 1
a first temperature adjusting circuit that is provided at the first mold and the second mold to adjust a temperature within a range where the second dimension of the second surfaces is greater than the first dimension of the first surfaces such that the temperature of the pair of first surfaces becomes higher than the temperature of the pair of second surfaces
Implementation Method 2
a second temperature adjusting circuit that is provided at the first mold and the second mold to adjust a temperature within a range where the second dimension of the second surfaces is smaller than the first dimension of the first surfaces such that the temperature of the pair of first surfaces within the range becomes lower than the temperature of the pair of first surfaces whose temperature is adjusted by the first temperature adjusting circuit
Data Source
AI summary
An injection molding apparatus includes a first mold and a second mold, a cavity formed by clamping the first mold and the second mold, and includes a portion where the ratio of a first dimension and a second dimension changes continuously such that a portion where the ratio of the first dimension of a pair of first surfaces, and the second dimension of a pair of second surfaces becomes 1 locates in an intermediate portion of the cavity in a longitudinal direction of the long shape; and a first temperature adjusting circuit that is provided at the first mold and the second mold to adjust a temperature within a range where the second dimension of the second surfaces is greater than the first dimension of the first surfaces such that the temperature of the pair of first surfaces becomes higher than the temperature of the pair of second surfaces.