Contact Lens Mold Tool Exchange for High-Speed Power Changeovers
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Solution Overview
Problem
The manufacturing of contact lenses, particularly soft contact lenses, faces challenges in achieving optical precision and maintaining quality at high production rates, as existing methods struggle to efficiently produce mold halves for various powers and types of lenses without compromising quality.
Innovation Solution
The use of single-use mold halves and an apparatus with a collet-exchange robot system that allows for rapid exchange of tool assemblies in injection molding machines, enabling the production of different lens powers and types by robotically moving and replacing collets in three dimensions, facilitating high-speed manufacturing of contact lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional manual tool exchange methods are used in injection molding machines, then operators can replace tool assemblies, but the process is time-consuming and reduces productivity
Solution Approach 1:
The system enables automatic tool assembly exchange without human operators. The robot autonomously removes spent tool assemblies from the injection molding machine and replaces them with fresh ones from the tool assembly holder, eliminating manual intervention and reducing exchange time.
Solution Approach 2:
Manual mechanical tool exchange by operators is replaced with an automated robotic system. The robot mechanically grasps, removes, and installs tool assemblies, substituting human labor with automated mechanical action to improve speed and consistency.
2Adaptability or versatility
If multiple tool assemblies are stored and exchanged manually, then different lens powers and types can be produced, but the complexity of managing and exchanging tools increases
Solution Approach 1:
The injection molding machine is designed with universal tooling capability to accept multiple different tool assemblies for producing various lens powers and types. The standardized interface allows different tool assemblies to be interchangeably mounted on the same machine, enabling one machine to perform multiple production functions.
Solution Approach 2:
A robot acts as an intermediary between the tool assembly holder and the injection molding machine. The robot manages the complex task of tool exchange, coordinating the removal of spent tools and installation of new ones, thereby simplifying the overall system operation despite handling multiple tool varieties.
3Productivity
If high speed manufacturing lines are used to manufacture contact lenses in large numbers, then production volume increases and cost per lens decreases, but maintaining optical precision and quality becomes more difficult
Solution Approach 1:
The system uses disposable single-use mold halves that are pre-manufactured with high optical precision. These precision mold halves are mounted on tool assemblies and used for injection molding. After a limited number of uses or when precision degrades, the entire tool assembly with the mold half is discarded and replaced, ensuring consistent optical quality without the complexity of maintaining and reconditioning precision tools.
Solution Approach 2:
The mold halves are pre-manufactured with the required optical precision before being mounted on tool assemblies. This preliminary preparation of precision components allows the high-speed injection molding process to produce lenses at high volumes while maintaining consistent optical quality, as the precision has already been established in the mold halves rather than being achieved during high-speed production.
Data Source
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AI summary
Methods and apparatus for exchanging tools and/or tool assemblies used to form different types of molds for in injection-molding machines, are described. The exchange of tools and/or tool assemblies is made using a robot. Contact lens mold halves and assemblies for molding contact lenses of different powers or types can be made with a single injection-molding apparatus.