Ophthalmic Lens Production Line for Parallel Multi-Lot Molding
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Solution Overview
Problem
Existing production lines for contact lenses using plastic lens molds are limited to producing a single type of lens at a time, require large stockpiles of molds with different geometries, and lack flexibility, leading to inefficient use of space and production time due to cumbersome lot changes.
Innovation Solution
A production line and method utilizing two injection-molding machines to concurrently produce front and base curve plastic lens molds within a cycle time of less than ten seconds, with a flexible layout allowing simultaneous production of different lens types and geometries, including a curing module with adjustable oven placement and a closed-loop rail system for efficient lens inspection and packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single injection-molding machine is used to produce lens molds, then the device complexity is reduced, but the productivity is limited because only one type of lens can be produced at a time
Solution Approach 1:
The production system is divided into multiple independent injection-molding machines, each dedicated to producing a specific type of lens mold. This segmentation allows parallel production of different lens types without interfering with each other, thereby increasing overall productivity while keeping each individual machine relatively simple in design.
2Ease of manufacture
If plastic lens molds are used instead of glass molds, then the manufacturing cost is reduced and ease of manufacture is improved, but the reusability is limited to single-use only
Solution Approach 1:
The patent employs plastic lens molds that are designed for single-use only. These inexpensive plastic molds are produced through injection-molding and discarded after forming one contact lens, eliminating the need for costly cleaning, maintenance, and sterilization procedures associated with reusable glass molds. The low cost and ease of manufacture of these disposable molds compensates for their limited reusability.
3Adaptability or versatility
If production lines are designed to produce multiple lens types simultaneously, then the adaptability is improved, but the device complexity increases due to the need for multiple injection-molding machines and complex coordination systems
Solution Approach 1:
The production line is segmented into multiple independent injection-molding machines, each specialized for producing a specific type of lens mold. This segmentation enables the system to produce multiple lens types simultaneously without requiring complex coordination mechanisms between different production units. Each machine operates autonomously, simplifying the overall system architecture while maintaining high adaptability.
Solution Approach 2:
The patent creates a universal production line configuration where multiple injection-molding machines can operate in parallel to produce different types of lens molds. This multi-functional setup allows the same production line infrastructure to handle various lens geometries and specifications by simply changing the mold types, thereby achieving high adaptability without proportionally increasing system complexity.
4Adaptability or versatility
If large stockpiles of different lens molds are maintained, then the adaptability is improved for producing various lens types, but the area required for storage increases
Solution Approach 1:
By using inexpensive, single-use plastic lens molds instead of expensive reusable glass molds, the system can maintain smaller inventories. The low cost of disposable molds allows for rapid replacement without the need for large storage spaces to house numerous expensive reusable molds. This approach reduces storage area requirements while maintaining the ability to produce various lens types.
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
Enables efficient, flexible production of multiple lens types with high quality and reduced downtime, utilizing space effectively by allowing simultaneous production of up to 32 different lots of lenses with a cycle time as low as two to five seconds.
Implementation Method 1
In injection-molding machines, a flowable hot thermoplastic material is injected at high pressure into casting dies through so-called hot runners
Implementation Method 2
The casting dies are shaped such that after curing of the hot thermoplastic material in the casting dies by cooling down, the plastic lens molds having the desired geometry are formed
Implementation Method 3
heating the chamber to a predetermined temperature to effect curing of the lens-forming material to form cured lenses in the closed plastic lens molds
Implementation Method 4
curing of the lens-forming material may be effected with the aid of UV-light and UV-photoinitiators contained in the lens-forming material, these UV-photoinitiators triggering photopolymerization and/or crosslinking of the lens-forming material upon being exposed to UV-light
Data Source
AI summary
An automated production line for the production of ophthalmic lenses comprises:a production line front end (1) comprising:a first injection-molding machine (10) and a second injection-molding machine (12)a casting module (14) comprisinga filling station (144) and a capping station (145);a stacking module (15) and a curing module (16);a destacking module (17) and a demolding and delensing modulea production line back end (2) comprising:an inspection module (21);Wherein the inspection module comprising a rail system in which self-driving shuttles carrying the inspection cuvettes are arranged on a closed-loop rail, wherein the rail system can be adapted to the available space in the production plant/hall using curves and straight portions in the manner known from a model railway.