Overmolded Optical Circuit Manufacturing Consistency

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Solution Overview

Problem

Existing methods for producing overmolded optical circuits face challenges in manufacturability, consistency, and distortion due to the high viscosity of fluoropolymers, leading to air pockets, inconsistent thicknesses, and warping, especially when creating complex fiber assemblies.

Innovation Solution

A method using self-leveling flowable overmolding materials and structural supports within molds to position and hold optical circuits in place, allowing for pre-curing and precise positioning to avoid distortion, and combining these approaches for consistent and complex assembly production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluoropolymer is applied by hand and buttered into the molds, then the optical circuit receives abrasion and chemical resistance protection, but the manufacturing process becomes prohibitively expensive, inconsistent, and produces air pockets and distorted circuits

Engineering Contradiction:
Improveabrasion and chemical resistanceVSAvoidmanufacturing cost and consistency
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the manual mechanical application method (buttering) with an automated injection molding system. The fluoropolymer is injected through a nozzle into the mold cavity under controlled conditions, eliminating hand application inconsistencies and reducing labor costs while maintaining protective coating quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent modifies the physical parameters of the fluoropolymer by heating it to reduce viscosity during injection molding. This temperature parameter change allows the material to flow properly into the mold cavity and around the optical circuit without requiring manual application, thereby improving manufacturing consistency and reducing defects.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If fluoropolymer is injected into the molds under high pressure, then the manufacturing process becomes automated and scalable, but the high pressure distorts and damages the optical circuit

Engineering Contradiction:
Improvemanufacturing scalabilityVSAvoidoptical circuit integrity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the temperature parameter of the fluoropolymer to reduce its viscosity before injection. This allows the material to be injected at lower pressures that do not distort the optical circuit, while still achieving complete mold filling and consistent coating thickness for scalable production.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary heating of the fluoropolymer to reduce its viscosity before the injection process. This preliminary action prepares the material to flow easily into the mold cavity at low pressure, protecting the optical circuit from damage while enabling automated scalable manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the fluoropolymer viscosity is reduced for easier injection, then the manufacturing process becomes more scalable, but the material may not provide adequate protective coating quality

Engineering Contradiction:
Improveinjection molding feasibilityVSAvoidcoating consistency and thickness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies controlled heating to reduce fluoropolymer viscosity only during the injection phase, then allows the material to cool and cure to form a consistent protective coating. This temporary parameter change enables scalable manufacturing while maintaining coating quality through controlled processing conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements controlled injection parameters and curing conditions to monitor and adjust the coating process. By controlling temperature, pressure, and injection rate, the system ensures consistent coating thickness and quality while maintaining scalability through repeatable processing parameters.

Inventive Principle:
Principle #23Feedback

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 enhances manufacturability by ensuring consistent overmolding without distortion, allowing for the production of complex optical fiber assemblies with improved abrasion and chemical resistance while maintaining the optical circuit's integrity.

Implementation Method 1

flowing a polymer in at least the first space

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

The method comprises (a) placing at least one flexible optical circuit in a bottom mold, the bottom mold defining a bottom overmold cavity having a bottom surface, the at least one flexible optical circuit having a substrate and a plurality of fibers adhered to the substrate, the substrate being disposed at least partly within or within the bottom overmold cavity to define a first space between the substrate and the bottom surface; (b) flowing a polymer in at least the first space; (c) placing a top mold over the bottom mold, the top mold defining a top overmold cavity and a top surface and a port defined in the top surface to access the top overmold cavity; (d) flowing a polymer in at least a portion of a second space between the top surface and the substrate; and (e) removing the bottom and top molds to release the overmolded optical circuit

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP3859418B1Overmolded optical circuits
Publication Date: 2024.05.01 TE CONNECTIVITY SOLUTIONS GMBH
  • EP3859418B1 patent drawingFigure 1a~1b
  • EP3859418B1 patent drawingFigure 1c~1d
  • EP3859418B1 patent drawingFigure 1e~1f

AI summary

A method of preparing an overmolded optical fiber assembly (150) comprising: (a) placing at least one flexible optical circuit (880) in a bottom mold (101), said bottom mold (101) defining a bottom overmold cavity (102) having a bottom surface (101a), said at least one flexible optical circuit (880) having a substrate (881) and a plurality of fibers (882) adhered to said substrate (881), said substrate (881) being disposed at least partly within said bottom overmold cavity (102) to define a first space (801) between said substrate (881) and said bottom surface (101a); (b) flowing a polymer (883) in at least said first space (801); (c) placing a top mold (120) over said substrate (881), said top mold (120) defining a top overmold cavity (121) and a top surface (121a) and a port (122) defined in said top surface (120a) to access said top overmold cavity (121), said substrate (881) defining a second space (802) between said top surface (120a) and said substrate (881); (d) flowing a polymer (884) in at least a portion of said second space (802); and (e) removing said bottom (101) and top (120) molds to release said overmolded optical circuit (150).