Three-Layer Eyeglass Frame Injection Molding

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Solution Overview

Problem

Existing eyeglass frames made of laminated plastic suffer from poor mechanical stability, color separation, and limited color options, with designs relying on shape variations for creativity due to color fading issues.

Innovation Solution

A method involving injection molding of three polyamide layers, where two external layers are overmolded on a central core, allowing for varied colors and enhanced stability, with the option of machining a three-layer plate for shape customization, using liquid dyes without heavy metals and a polyurethane varnish for protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If laminated plastic plates are used to manufacture eyeglass frames, then color variety is available, but mechanical stability deteriorates and layers separate

Engineering Contradiction:

Improvecolor varietyVSAvoidmechanical stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a central core made of plastic material and two external layers made of different plastic materials. This composite construction provides both mechanical stability through the integrated structure and color variety through the different materials used in the core and external layers, resolving the contradiction between reliability and adaptability.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If traditional laminated frames are used, then manufacturing is simple, but color fading occurs over time

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcolor stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameters by using specific plastic materials with inherent color stability properties. The external layers and core are made from plastic materials that resist fading, maintaining color stability over time while preserving the manufacturing simplicity through the injection molding process.

Inventive Principle:

Principle #35Parameter changes

3Strength

If designers focus on shape variations, then color limitations are avoided, but mechanical stability improves

Engineering Contradiction:

Improvemechanical stabilityVSAvoidcolor choice

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The composite structure with a central core and external layers enables both mechanical strength and color variety. The different plastic materials used in the core and external layers provide diverse color options, while the integrated composite construction ensures mechanical stability, eliminating the need to rely solely on shape variations.

Inventive Principle:

Principle #40Composite materials

4Reliability

If three-layer structure with overmolding is used, then mechanical stability improves, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical stabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The injection molding process is designed to automatically form the three-layer structure with proper integration during the molding process itself. The preliminary design of the mold system incorporates the overmolding sequence, eliminating the need for separate assembly steps and reducing manufacturing complexity despite the multi-layer structure.

Inventive Principle:

Principle #10Preliminary action

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 method provides eyeglass frames with excellent mechanical and chemical stability, infinite color variety, and cost-effective production, eliminating color fading while meeting regulatory standards, and reducing manufacturing time and equipment costs.

Implementation Method 1

manufacturing by injection molding of plastic material two layers (5, 6) of the element to be manufactured of the eyeglass frame... a third layer (7) of the element to be manufactured, overmolded with the first (5) and second (6) layers arranged on either side of said third layer

Methodology Applied

Scientific EffectInjection molding:

Implementation Method 2

overmolded with the first (5) and second (6) layers arranged on either side of said third layer... provides an excellent mechanical and physico-chemical stability of said element

Methodology Applied

Scientific EffectOvermolding:

Data Source

PatentUS9656433B2Method of manufacturing an element forming an eyeglass frame, and element obtained by said method

Publication Date: 2017.05.23 PLASTINAX AUSTRAL LTD

AI summary

This method of manufacturing an element forming part of an eyeglass frame includes the steps of: manufacturing by molding by injection of plastic material two layers of the element to be manufactured of the eyeglass frame; overmolding by means of these two layers a central core, to obtain an eyeglass frame element comprising three layers, its first and second layers forming external layers and its central core forming an internal layer.