Ophthalmic Lens Mold Filling With Dynamic Flow Rate Control
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Solution Overview
Problem
The manual molding of high-refractive index ophthalmic lenses is inefficient, leading to low production yield and operator exposure to hazardous materials, with challenges in minimizing flow perturbations and handling varied mold volumes and shapes.
Innovation Solution
An automated machine that acquires input values related to the mold assembly's internal volume to control the flow rate of molding material, ensuring precise filling without overflow, using scanning means to determine the filling aperture width and controlling the flow rate profile to optimize filling speed and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual molding is used to fill the mold assembly, then operator control over filling process is maintained, but production efficiency is low and operator exposure to hazardous materials occurs
Solution Approach 1:
The patent replaces the manual mechanical filling operation with an automated injection system. The filling means includes an injection needle connected to a reservoir of molding material, controlled by control means that automatically regulate the flow rate and injection timing, eliminating the need for operators to manually handle hazardous polymerizable synthetic materials while maintaining precise control over the filling process.
Solution Approach 2:
The system enables self-service operation where the automated filling means independently performs the filling operation based on pre-programmed parameters. The control means automatically adjusts flow rate profiles and injection timing without requiring operator intervention, allowing the system to serve itself in completing the molding operation while improving safety and efficiency.
2Productivity
If high flow rate is used to fill the mold assembly, then production speed increases, but flow perturbations occur that generate haze and reduce lens transparency
Solution Approach 1:
The patent implements dynamic flow rate control where the flow rate is not constant but varies during the filling process. The control means adjusts the flow rate profile in real-time, using higher flow rates during initial filling and reducing flow rate as the mold approaches full capacity. This dynamic adjustment prevents flow perturbations and air entrapment that would cause haze, while still maintaining high overall filling speed.
Solution Approach 2:
The filling process employs periodic action through staged flow rate adjustment. The control means implements multiple phases of filling with different flow rate characteristics, including acceleration phases and deceleration phases, ensuring smooth material flow throughout the process. This periodic modulation of flow rate prevents turbulence and ensures uniform filling without compromising transparency.
3Manufacturing precision
If the mold assembly is manually inclined during filling, then flow perturbations are minimized, but the process is time-consuming and reduces production yield
Solution Approach 1:
The patent replaces the mechanical inclination process with an automated injection system that maintains the mold in a fixed horizontal position. The filling means, equipped with controlled injection through a needle, delivers material directly to the mold cavity without requiring physical repositioning or tilting of the mold assembly, thereby eliminating time loss while maintaining flow uniformity through precise injection control.
Solution Approach 2:
The injection needle acts as an intermediary that bridges the reservoir and mold cavity, enabling controlled material delivery without direct contact or manipulation of the mold assembly. This intermediary mechanism allows precise flow control and eliminates the need for mechanical inclination, maintaining both flow uniformity and process efficiency.
4Object-affected harmful factors
If protective clothing is required for operators, then safety is improved, but operational efficiency decreases and production cost increases
Solution Approach 1:
The patent replaces manual operations with automated systems that eliminate the need for operators to wear protective clothing during the filling process. The automated filling means and control system perform all operations that previously required human intervention, thereby improving safety by removing operators from exposure to hazardous materials while simultaneously improving operational efficiency by eliminating the constraints imposed by protective equipment.
Data Source
AI summary
The present disclosure relates to a machine for an automated filling of a mold assembly for molding an ophthalmic lens, comprising: filling means to fill the mold assembly with a molding material through a filling aperture provided in the mold assembly, acquiring means to acquire an input value linked to the internal volume of the mold assembly, and control means for controlling the flow rate of molding material injected by the filling means in the mold assembly according to a flow rate profile deduced as a function of said input value.