In-Mold Vibratile Injection Compression Molding for Optical Components
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Solution Overview
Problem
Current injection molding techniques for optical components, such as hybrid optical elements (HOEs) and aspherical lenses, face challenges with form error, groove filling rate, and residual stress, which affect the optical quality and mechanical strength of the molded parts due to material shrinkage, high temperature, high pressure, and high shear stress.
Innovation Solution
The in-mold vibratile injection compression molding method uses piezoelectric actuators to reciprocally vibrate the molding material within a cavity, maintaining the material temperature between the glass transition and melting temperatures, and adjusting the filling flow velocity to precisely inject the material into microstructures, thereby minimizing form error and residual stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection molding is used to mold optical components, then mass production and low cost are achieved, but form error, groove filling rate, and residual stress affect optical quality and mechanical strength
Solution Approach 1:
The patent applies ultrasonic vibration to the injection molding process to improve material flow and filling characteristics. The vibration energy helps the molding material better fill microstructures and reduces form error while maintaining production efficiency.
Solution Approach 2:
The patent modifies process parameters including temperature control (maintaining material temperature between glass transition and melting temperatures) and injection parameters to optimize both precision and productivity. By carefully controlling these parameters, the method achieves high groove filling rate while reducing residual stress.
2Manufacturing precision
If high temperature and high pressure are applied during injection molding, then material flow into microstructures is improved, but residual stress increases affecting optical property and mechanical strength
Solution Approach 1:
The patent optimizes temperature and pressure parameters to achieve complete groove filling while minimizing residual stress. Specifically, the material temperature is controlled between glass transition and melting temperatures, and injection pressure is adjusted to ensure microstructure filling without excessive stress.
Solution Approach 2:
Ultrasonic vibration assists material flow into microstructures at lower pressure levels, reducing the need for high pressure injection. This vibration-assisted filling improves groove filling rate while significantly reducing residual stress in the molded part.
3Object-affected harmful factors
If injection compression molding is used to reduce residual stress, then optical quality is improved, but process complexity and difficulty of controlling groove filling rate increase
Solution Approach 1:
The patent introduces ultrasonic vibration to simplify the injection compression process. The vibration assists material flow and reduces the complexity of pressure control while effectively reducing residual stress. This makes the process easier to control compared to conventional injection compression molding.
Solution Approach 2:
The patent implements pressure sensing and feedback control to monitor and adjust injection parameters in real-time. This feedback mechanism simplifies the control of groove filling rate and residual stress by automatically adjusting process parameters based on actual conditions.
4Manufacturing precision
If piezoelectric actuators are used to vibrate the movable core in multiple directions, then material injection precision into microstructure is improved, but device complexity increases
Solution Approach 1:
The patent uses piezoelectric actuators to generate ultrasonic vibration in the movable core, improving material injection precision into microstructures. The actuators are integrated into the existing molding apparatus, minimizing additional complexity while achieving enhanced filling precision.
Solution Approach 2:
The piezoelectric actuators serve multiple functions: they provide ultrasonic vibration for improved filling, enable bidirectional movement control, and assist in pressure distribution. This multi-functionality reduces the need for separate systems, balancing precision improvement with acceptable device complexity.
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
This method improves the precision and quality of optical components by enhancing the groove filling rate and reducing residual stress, leading to better optical image quality and mechanical strength.
Implementation Method 1
a first piezoelectric actuator and a second piezoelectric actuator, wherein the first piezoelectric actuator is coupled to the movable core for reciprocally vibrating the movable core along a first direction based on a pressure sensing signal, and the second piezoelectric actuator is coupled to the movable core for reciprocally vibrating the movable core along a second direction different from the first direction
Implementation Method 2
a pressure sensor, wherein the pressure sensor is disposed in the stationary structure and coupled to the fixed core for sensing a pressure value of the cavity and outputting a pressure sensing signal associated with the pressure value
Data Source
AI summary
An in-mold vibratile injection compression molding method and molding apparatus thereof are described. While performing a filling stage, a first piezoelectric actuator and a second piezoelectric actuator are use to vibrate the molding material along at least two directions for precisely filling the molding material into the micro-structure by adjusting the filling flow velocity of the molding material associated with the proper molding material temperature and by maintaining a molding material temperature of a skin solidified layer in the cavity between a glass transition temperature and a melting temperature in order to avoid the form error, to increase the groove filling rate and to improve the residual stress.