Optical Element Molding Mold Set with Variable Friction
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Solution Overview
Problem
In optical element molding, differences in volume between mold spaces lead to uneven filling times, causing glass to flow into gaps and resulting in burrs and increased press time, which complicates the molding of lenses with meniscus shapes and increases production costs.
Innovation Solution
An optical element molding mold set with a third mold on the outer periphery having different friction coefficients on opposite sides of the first and second molds, allowing for controlled flow of the molding material by adjusting speeds at which it fills the outer periphery, preventing glass from flowing into gaps and reducing burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If upper and lower molds are used to simultaneously mold optical surfaces, then molding efficiency is improved, but uneven filling times cause glass to flow into gaps creating burrs
Solution Approach 1:
The inner peripheral surface of the outer peripheral mold is designed with different friction coefficients at different locations. Specifically, the friction coefficient is made larger on the side where the cavity volume is smaller and shorter in the optical axis direction, and smaller on the side where the cavity volume is larger. This local differentiation of friction characteristics compensates for the volume difference between upper and lower mold spaces, enabling uniform filling times and preventing burr formation while maintaining high molding efficiency
Solution Approach 2:
The invention changes the friction coefficient parameter of the mold surface to control glass flow. By adjusting the friction coefficient distribution on the inner peripheral surface of the outer peripheral mold, the flow speed of glass is regulated to achieve simultaneous filling of upper and lower mold cavities, thereby preventing overflow and burr formation
2Manufacturing precision
If temperature difference between upper and lower molds is used to delay transformation, then filling time difference is compensated, but press time increases and productivity decreases
Solution Approach 1:
Instead of applying temperature difference to the entire mold, the invention applies friction coefficient differentiation only to the inner peripheral surface of the outer peripheral mold. This localized approach addresses the filling time difference without requiring extended press time for temperature control, thus maintaining productivity
3Manufacturing precision
If outer peripheral portions are filled simultaneously, then molding precision is improved, but glass flows into gaps between molds creating burrs
Solution Approach 1:
The inner peripheral surface of the outer peripheral mold is designed with spatially varying friction coefficients. The side with smaller cavity volume has larger friction coefficient to slow glass flow, while the side with larger cavity volume has smaller friction coefficient to accelerate flow. This balances the filling timing and prevents glass from overflowing into the gap between molds, eliminating burr formation
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 solution prevents burr formation, reduces the need for chamfering, and maintains surface accuracy, thereby enhancing productivity and reducing costs by ensuring uniform filling and minimizing overfilling issues.
Implementation Method 1
an inner peripheral surface of the third mold has different friction coefficients between one side and another side in an opposite direction of the first mold and the second mold
Implementation Method 2
speeds are adjusted at which the molding material that has been pressurized in the cavity flows toward one end and another end
Data Source
AI summary
An optical element molding mold set includes a first mold and a second mold that are opposite to each other, and a third mold that is located on an outer periphery of a cavity between the first mold and the second mold, and an inner peripheral surface of the third mold has different friction coefficients between one side and another side in an opposite direction of the first mold and the second mold.