Occulting Optics for Melt Pool Edge Temperature Measurement

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Solution Overview

Problem

In additive manufacturing, it is challenging to accurately measure the temperature and cooling rate of areas near the edge of the melt pool and surrounding regions due to the high intensity of thermal emissions from the energy source, which hinders the prediction and control of microstructure quality.

Innovation Solution

An optical system with an occulting device is used to block or reduce the intensity of thermal emissions from the energy source, vapor, and melt pool, allowing for the detection of fainter emissions from solidifying regions, enabling more accurate temperature measurements and predictions of microstructure quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If thermal emissions from the energy source and melt pool are measured directly, then the intensity of thermal emissions is high, but the measurement precision of solidifying regions deteriorates due to overwhelming brightness from the energy source

Engineering Contradiction:
Improvethermal emissions intensityVSAvoidtemperature measurement precision
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The optical system is segmented into multiple channels: one for capturing thermal emissions from the energy source and melt pool, and another for capturing emissions from solidifying regions. The occulting device segments the field of view to block out the overwhelming brightness from the energy source while allowing detection of fainter emissions from solidifying regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The occulting device acts as an intermediary element that selectively blocks thermal emissions from the energy source and melt pool while allowing emissions from solidifying regions to pass through to the detector. This mediator enables the detection of faint signals that would otherwise be overwhelmed by brighter sources.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the energy source delivers high energy to form the melt pool, then the manufacturing precision is improved, but the temperature measurement of surrounding regions deteriorates due to excessive thermal emissions

Engineering Contradiction:
Improvemicrostructure quality controlVSAvoidtemperature measurement precision
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The harmful thermal emissions from the energy source are extracted and removed from the detection path using the occulting device. This allows the optical system to measure temperature in surrounding regions without interference from the high-energy source, enabling simultaneous high manufacturing precision and accurate temperature measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

3Use of energy by moving object

If the optical system detects thermal emissions from all regions, then the energy utilization is high, but the detection of faint emissions from solidifying regions becomes difficult due to overwhelming signals

Engineering Contradiction:
Improvethermal emissions detection efficiencyVSAvoiddetection difficulty
Core Design Contradiction:
Use of energy by moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The occulting device converts the harmful overwhelming brightness from the energy source into a beneficial filtering mechanism. By blocking out the intense emissions, it creates favorable conditions for detecting the fainter but critically important emissions from solidifying regions, turning a detection obstacle into a solution.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 approach allows for more precise temperature measurements of solidifying regions, enhancing the prediction and control of microstructure quality in additively manufactured components.

Implementation Method 1

the occulting device is configured to occult at least part of thermal emissions produced by the energy and the melt pool and transmit at least some thermal emissions produced by the cooling region

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP4005707A1Occulting device for optical system in additive manufacturing systems
Publication Date: 2022.06.01 ROLLS ROYCE CORP
  • EP4005707A1 patent drawingFigure 1
  • EP4005707A1 patent drawingFigure 2
  • EP4005707A1 patent drawingFigure 3~4

AI summary

An additive manufacturing system may include an energy delivery device configured to deliver energy to a component to form a melt pool at least partially surrounded by a cooling region; and an optical system comprising: an imaging device; and an occulting device, wherein the occulting device is configured to occult at least part of thermal emissions produced by the energy and the melt pool and transmit at least some thermal emissions produced by the cooling region.