Optical Mold Temperature and Vacuum Control for 3D Lens Film Printing
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Solution Overview
Problem
Existing 3D FDM printing of thermoplastic films for ophthalmic lenses faces issues such as voids between filament strands and layers, poor adhesion, warpage, and rough surfaces due to limited force and heat control, leading to poor optical properties, mechanical strength, and dimension accuracy.
Innovation Solution
A method involving temperature control of the optical mold using a temperature control circuitry with electric heating elements and microfluidic channels, combined with vacuum application, to adjust and maintain specific temperatures during the printing of thermoplastic layers, ensuring proper adhesion and mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 3D printing is used to print thermoplastic films on optical molds, then the printing process can be performed, but voids between layers and poor adhesion occur resulting in poor optical and mechanical properties
Solution Approach 1:
The patent applies parameter changes by precisely controlling temperature and vacuum parameters during the printing process. The mold temperature is controlled within a specific range (10°C lower to 30°C higher than glass transition temperature) and vacuum pressure is applied during layer formation to eliminate voids and improve adhesion between thermoplastic layers, thereby resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent utilizes phase transitions of thermoplastic materials by controlling the mold temperature relative to the glass transition temperature of the thermoplastic film. This phase transition control enables proper layer bonding and eliminates voids, improving both adhesion quality and layer bonding precision simultaneously.
2Manufacturing precision
If conventional 3D printing is used with limited force and heat control, then the printing process can be performed, but warpage and rough surfaces occur resulting in poor dimension accuracy
Solution Approach 1:
The patent improves dimension accuracy by implementing precise temperature control parameters. The mold temperature is maintained within a specific range relative to the glass transition temperature of the thermoplastic material, and vacuum pressure is applied during printing. These controlled parameter changes prevent warpage and surface roughness, achieving high dimension accuracy.
3Reliability
If temperature control is applied to improve layer adhesion, then adhesion quality improves, but process complexity increases
Solution Approach 1:
The patent manages device complexity by implementing temperature control with a specific parameter range (10°C lower to 30°C higher than glass transition temperature) rather than requiring ultra-precise temperature control. This approach maintains layer adhesion quality while avoiding excessive system complexity.
4Reliability
If multiple thermoplastics are used to form complex structures, then optical and mechanical properties improve, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by using different thermoplastic materials for different layers based on specific functional requirements. Each layer can be optimized for particular optical or mechanical properties, allowing complex structures with enhanced performance while managing manufacturing complexity through systematic material selection.
Solution Approach 2:
The patent utilizes composite materials by combining multiple thermoplastic materials with different properties in a single printed structure. This enables the final product to exhibit both improved optical clarity and mechanical strength, resolving the contradiction between reliability 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
Improves optical clarity, mechanical strength, and accuracy of thermoplastic films by enhancing adhesion and reducing warpage, resulting in high-quality, dimensionally stable ophthalmic lens films with precise replication of optical designs.
Implementation Method 1
applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold
Implementation Method 2
adjusting, by temperature control circuitry, a temperature of the optical mold to a first temperature
Implementation Method 3
annealing the first layer and the second layer once the temperature of the optical mold has reached the third temperature
Implementation Method 4
the first temperature may be between 10° C. lower than a glass transition temperature of the thermoplastic film and 30° C. higher than the glass transition temperature
Data Source
AI summary
The present disclosure relates to a method of printing a thermoplastic film on an optical mold comprising adjusting a temperature of the optical mold to a first temperature, printing a first layer of the thermoplastic film on the optical mold once the temperature of the optical mold has reached the first temperature, applying a vacuum to the optical mold to hold the thermoplastic film on the optical mold, adjusting the temperature of the optical mold to a second temperature, printing a second layer of the thermoplastic film on the first layer of the thermoplastic film once the temperature of the optical mold has reached the second temperature, adjusting the temperature of the optical mold to a third temperature, annealing the first layer and the second layer once the temperature of the optical mold has reached the third temperature, and removing the vacuum from the optical mold permitting removal of the thermoplastic film including the annealed first layer and the annealed second layer from the optical mold.