FDM 3D Printing of Transparent Optical Wafers With Void Reduction

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Solution Overview

Problem

Existing FDM 3D printing methods face challenges in producing optical wafers with high clarity, accurate dimensions, and smooth surfaces due to issues like voids, warpage, and poor surface quality, which are exacerbated by temperature gradients and weak interlayer bonding.

Innovation Solution

Optimizing FDM 3D printing parameters, including nozzle and plate temperatures, layer thickness, and surface treatments like acetone application on the building plate, combined with specific printing patterns and coatings to enhance adhesion and surface smoothness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If FDM 3D printing is used to manufacture optical wafers, then manufacturing complexity is reduced and productivity is improved, but manufacturing precision deteriorates due to voids, warpage, and poor surface quality

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidwafer clarity and surface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing printing temperature (200-300°C), layer thickness (0.01-0.1mm), and printing speed to achieve high clarity wafers. By controlling these parameters, the process resolves the contradiction between manufacturing efficiency and precision, producing optical wafers with minimal defects while maintaining productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by applying acetone or other solvents to the building plate before printing to create a controlled surface condition. This preliminary treatment prevents voids and improves adhesion, ensuring high surface quality and clarity from the first layer while maintaining efficient manufacturing

Inventive Principle:
Principle #10Preliminary action

2Productivity

If printing speed is increased to improve productivity, then manufacturing time is reduced, but manufacturing precision deteriorates due to voids and poor interlayer bonding

Engineering Contradiction:
Improveprinting speedVSAvoidinterlayer bonding quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by optimizing the relationship between printing speed, temperature, and layer thickness. By adjusting these parameters together rather than maximizing speed independently, the process maintains high productivity while ensuring proper interlayer bonding and minimizing voids through controlled deposition and fusion conditions

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If temperature is increased to improve material flow and reduce voids, then manufacturing precision improves, but temperature control complexity increases and energy consumption rises

Engineering Contradiction:
Improvewafer density and void reductionVSAvoidtemperature control range
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The patent applies parameter changes by optimizing printing temperature within a specific range (200-300°C) and using heated building plates at controlled temperatures. This controlled thermal approach ensures proper material flow and void reduction while maintaining manageable temperature control and energy consumption through targeted heating rather than excessive temperature increases

Inventive Principle:
Principle #35Parameter changes

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 wafers with high clarity, minimal defects, and precise dimensions, achieving glossy surfaces and improved mechanical stability.

Implementation Method 1

FDM (Fused Deposition Modeling), also called FFF (Fused Filament Fabrication), is an additive manufacturing technology that produces an object by extruding polymer in an amorphous state through nozzle(s) to form layers as the polymer material hardens after extrusion

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

surface treatments like acetone application on the building plate, combined with specific printing patterns and coatings to enhance adhesion and surface smoothness

Methodology Applied
Scientific EffectSurface treatment: Coatings

Data Source

PatentEP4197742B1Manufacturing of highly transparent wafers using FDM 3D printing
Publication Date: 2025.09.03 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP4197742B1 patent drawingFigure 1
  • EP4197742B1 patent drawingFigure 2
  • EP4197742B1 patent drawingFigure 3A~3B

AI summary

A fused filament fabrication 3D printing method for fabricating an optical article includes applying a surface treatment to a building plate; heating the building plate to a predetermined plate temperature; dispensing a thermoplastic through a nozzle set at a predetermined nozzle temperature onto the building plate while translating the nozzle or the building plate according to a first predetermined pattern at a predetermined printing speed to form a first layer; and solidifying the first layer, wherein a range of the predetermined plate temperature is between 30°C lower than a glass transition temperature of the thermoplastic and 20°C higher than the glass transition temperature of the thermoplastic, and a range of the predetermined nozzle temperature is at least 100 °C higher than the glass transition temperature of the thermoplastic, and at least 50 °C lower than a degradation temperature of the thermoplastic.