Optical Lens Manufacturing with FDM Layers and Injection Over-Molding

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Solution Overview

Problem

FDM 3-D printing is unable to produce optical quality lenses due to its inability to achieve fine enough resolution, resulting in rough surfaces and poor layer adhesion, making it unsuitable for optical lens production.

Innovation Solution

A method involving a transparent thermoplastic carrier with a smooth surface, where additional transparent layers with specific light filtering properties are printed using an FDM 3-D printer, followed by an injection over-molding process to fuse bond the layers to a thermoplastic substrate, forming an optical lens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If FDM 3-D printing is used to manufacture optical lenses, then manufacturing flexibility and customization are improved, but manufacturing precision and surface quality deteriorate due to layering effects and rough surfaces

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidsurface quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The manufacturing process is divided into two distinct segments: first, a master pattern is created using FDM 3-D printing for design flexibility; second, this pattern is used to create a mold for injection molding the final optical lens. This segmentation allows each process to optimize for its strength - 3-D printing for adaptability and injection molding for precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An intermediary master pattern serves as the bridge between the 3-D printing process and the final lens production. This master pattern is printed with high precision requirements and then used to create injection molds, transferring the design flexibility while eliminating the surface quality issues of direct 3-D printed lenses.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If FDM 3-D printing is used to produce functional wafers with light filtering functions, then production cost and time for customization are reduced, but manufacturing precision and optical quality deteriorate due to layer adhesion issues and anisotropic properties

Engineering Contradiction:
Improveproduction efficiencyVSAvoidoptical quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The master pattern incorporating light filtering functions is pre-manufactured using 3-D printing with preliminary optimization of printing parameters (layer thickness, infill patterns, material selection) to minimize anisotropic effects. This preliminary action allows the functional properties to be established before the final high-precision lens manufacturing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Printing parameters such as layer thickness, extrusion temperature, and printing speed are optimized to reduce anisotropic properties and improve layer adhesion. The material composition is also adjusted to achieve better optical properties while maintaining the productivity benefits of additive manufacturing for the master pattern.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If FDM 3-D printing is used to manufacture optical lenses, then ease of manufacture and customization capability are improved, but manufacturing precision and resolution deteriorate due to inherent layering resolution limits

Engineering Contradiction:
Improvemanufacturing easeVSAvoidresolution
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The manufacturing process is segmented into master pattern creation (using 3-D printing for ease of manufacture) and final lens production (using injection molding for precision). This allows each segment to optimize for its respective strength without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The master pattern serves as a copy or template that captures the design complexity and customization features. This pattern is then replicated through injection molding to produce the final lens with high precision, avoiding the need to directly 3-D print the final optical component.

Inventive Principle:
Principle #26Copying

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

The method produces optical lenses with smooth surfaces and integrated light filtering functions, overcoming the limitations of FDM 3-D printing by ensuring compatibility and bonding strength between layers.

Implementation Method 1

performing an injection over-molding process to fuse bond the functional layer to a thermoplastic substrate thereby forming the optical lens

Methodology Applied
Scientific EffectFusion bonding: Welding

Data Source

PatentEP3888894B1Method of manufacturing an optical lens
Publication Date: 2025.08.06 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP3888894B1 patent drawingFigure 1
  • EP3888894B1 patent drawingFigure 2
  • EP3888894B1 patent drawingFigure 3

AI summary

A method of manufacturing an optical lens (417) using a 3-D printer (105) and injection over-molding (415), is herein disclosed. The method includes obtaining a transparent thermoplastic (TP) carrier (410) with at least one smooth surface, printing, via a 3-D printer (105) on the side opposite to the at least one smooth surface of the transparent TP carrier (410), at least one transparent layer (420) using a thermoplastic filament (403), each transparent layer (420) having a predetermined light filtering property, thereby forming a functional layer; and performing an injection over-molding process (415) to fuse bond the functional layer to a thermoplastic substrate thereby forming the optical lens (417).