Confocal Sensor Verification for Injection Molding Insert Mounting

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Solution Overview

Problem

Inaccurate mounting of molding inserts to tooling plates in injection-molding apparatuses leads to imperfect lens molds, resulting in decreased production yield and lenses that do not meet specifications, due to issues like particle interference and misalignment.

Innovation Solution

A method and system using a confocal sensor to verify the accurate mounting of molding inserts by measuring distances between the insert's surface and the tooling plate, ensuring the difference is within a predetermined threshold, and utilizing a processor to confirm accurate alignment based on pre-defined target distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual mounting of molding inserts to tooling plates is performed, then ease of operation is improved, but manufacturing precision deteriorates due to misalignment and particle interference

Engineering Contradiction:
Improveease of mountingVSAvoidmounting precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces manual mechanical mounting operations with an automated optical measurement system. A confocal sensor automatically measures the distance between the molding insert surface and tooling plate reference plane, eliminating the need for manual alignment and particle removal operations, thereby maintaining ease of operation while dramatically improving mounting precision

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

Solution Approach 2:

The system enables self-verification of mounting accuracy through automated measurement. The confocal sensor and processor work together to automatically detect whether the mounting precision meets specifications without requiring manual inspection or intervention, allowing the mounting process to self-correct or self-verify

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If automated measurement system is implemented, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvemounting precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a confocal sensor as an intermediary measurement device between the molding insert and the verification system. This intermediary component enables precise non-contact measurement of the distance between the insert surface and tooling plate, achieving high manufacturing precision without requiring complex direct measurement mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical alignment and measurement mechanisms with an optical confocal measurement system. The confocal sensor uses optical fields instead of mechanical contact to measure mounting precision, simplifying the overall device architecture while maintaining high precision

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

3Manufacturing precision

If inserts are carefully inspected before mounting, then manufacturing precision is improved, but loss of time increases due to additional inspection steps

Engineering Contradiction:
Improveinsert qualityVSAvoidinspection time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary inspection of insert quality during the mounting verification process itself. The confocal sensor measures the distance between the insert surface and tooling plate, which inherently verifies both mounting precision and insert integrity in a single operation, eliminating separate pre-mounting inspection steps

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the insert quality inspection function with the mounting verification function into a single measurement operation. The confocal sensor simultaneously verifies both the insert's surface integrity and its mounting accuracy, reducing the total inspection time while maintaining comprehensive quality control

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If multiple lens molds with different specifications are produced, then adaptability is improved, but reliability deteriorates due to incorrect insert mounting

Engineering Contradiction:
Improveproduction flexibilityVSAvoidmounting accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the confocal sensor continuously measures the distance between the molding insert surface and tooling plate reference plane. The processor compares this measured distance with the expected distance for the specific lens mold being produced, providing immediate feedback to verify correct insert mounting for each different mold specification

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses parameter changes to verify mounting accuracy for different lens mold specifications. The system adjusts the expected distance parameter based on the specific lens mold being produced, and the confocal sensor measures whether the actual mounting matches this parameter, ensuring reliability across different production configurations

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

Ensures accurate mounting of molding inserts, preventing particle interference and misalignment, thereby increasing production yield by ensuring lenses meet specifications and maintaining optical quality.

Implementation Method 1

providing a confocal sensor having a measurement beam; arranging the confocal sensor relative to the tooling plate such that a reference plane of the confocal sensor as well as a reference plane of the tooling plate are normal to the mounting axis

Methodology Applied
Scientific EffectConfocal sensing:

Data Source

PatentEP4301573B1Method for verifying the accurate mounting of molding inserts to a tooling plate of an injection-molding apparatus for molding ophthalmic lens molds
Publication Date: 2024.12.11 ALCON INC
  • EP4301573B1 patent drawingFigure 1~2
  • EP4301573B1 patent drawingFigure 3~4
  • EP4301573B1 patent drawingFigure 5

AI summary

A method for verifying whether a molding insert (1a, 1b) is accurately mounted to a tooling plate (2a, 2b) comprises the steps of: a) providing a confocal sensor (3a, 3b); b) arranging the confocal sensor (3a, 3b) such that a confocal sensor reference plane (32a, 32b) as well as a tooling plate reference plane (22a, 22b) are normal to a mounting axis (21a, 21b) of the tooling plate and spaced from each other by a predetermined first distance (d1, e1); c) measuring a second distance (d2, e2) between the confocal sensor reference plane (32a, 32b) and a central impingement location (11a, 11b) on a molding surface (12a, 12b) of the molding insert (1a, 1b); d) based on the measured second distance (d2, e2) as well as based on the predetermined first distance (d1, e1), determining a third distance (d3, e3) of the central impingement location (11a, 11b) relative to the tooling plate reference plane (22a, 22b); e) comparing the third distance (d3, e3) with a predetermined target distance, and f) determining that the molding insert (1a, 1b) is accurately mounted to the tooling plate (2a, 2b) if the difference between the third distance (d3, e3) and the predetermined target distance is less than a threshold difference.