Ceramic-Coated Optical Molds for Long-Life Plastic Lens Casting
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Solution Overview
Problem
Existing devices for casting optical elements, particularly spectacle lens blanks, are limited by a short lifespan and high material and energy consumption due to frequent reworking, necessitating a large number of molds and labor-intensive processes.
Innovation Solution
A device comprising two mold parts made of reaction-bonded silicon-infiltrated silicon carbide (SiSiC) with at least one ceramic layer, such as silicon carbide, aluminum oxide, or zirconium oxide, which significantly increases the number of casting cycles to 10,000 to 100,000 without reworking, reducing material and energy costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If glass molds are used for casting plastic optical elements, then the molds can be manufactured using existing thermal molding processes, but the mold lifespan is limited to approximately 200 casting cycles requiring frequent reworking
Solution Approach 1:
The patent applies composite materials by combining a metallic base body (made from sintered metal powder) with a ceramic functional layer (such as aluminum oxide, silicon carbide, or zirconium oxide). This composite structure provides both the mechanical strength of metal and the wear resistance of ceramic, enabling the mold to withstand up to 10,000 casting cycles without reworking, compared to only 200 cycles for conventional glass molds.
2Productivity
If the number of molds is increased to meet production demands, then production capacity is maintained, but material and energy consumption increase significantly
Solution Approach 1:
The patent changes the material parameters of the mold by transitioning from glass to a composite of metal base body with ceramic coating. This parameter change in material composition enables the mold to maintain its functional surface for up to 10,000 casting cycles, reducing the frequency of reworking and thereby decreasing overall energy consumption in production while maintaining or increasing productivity.
3Duration of action of stationary object
If frequent reworking of molds is performed to extend their lifespan, then mold utilization is improved, but labor intensity and production costs increase
Solution Approach 1:
The patent employs composite materials with a ceramic functional layer on a metal base body, where the ceramic layer provides exceptional wear resistance. This material choice eliminates the need for frequent reworking operations, as the mold can undergo up to 10,000 casting cycles without requiring surface reworking, thereby simplifying the manufacturing process and reducing labor intensity.
4Manufacturing precision
If glass molds are used, then the casting process can proceed with conventional materials, but the precision and quality require subsequent mechanical processing
Solution Approach 1:
The patent uses composite materials where the ceramic functional layer (such as aluminum oxide or silicon carbide) provides an extremely hard and wear-resistant surface that maintains high precision throughout the mold's lifecycle. This eliminates the need for subsequent mechanical processing steps like grinding and polishing, allowing the mold to be used for up to 10,000 casting cycles while maintaining surface precision, thereby significantly improving production efficiency.
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 device achieves a prolonged mold lifespan, reducing the need for molds and energy consumption, while maintaining high precision and quality, thus enhancing sustainability and efficiency in optical element production.
Implementation Method 1
each mold part consists of a base body made of reaction-bonded silicon-infiltrated silicon carbide (SiSiC)
Implementation Method 2
at least one layer of a ceramic material is arranged on the base body
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a device for casting optical elements from plastic, wherein the device comprises two mold parts, each mold part consisting of a base body made of reaction-bonded silicon-infiltrated silicon carbide and wherein at least one layer of a ceramic material is arranged on the base body. The invention further relates to a method for manufacturing a device according to the invention.