Thermal Camera Array for Additive Manufacturing Defect Detection

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Solution Overview

Problem

Existing non-destructive quality control methods for additive manufacturing, such as thermography and X-ray tomography, require high-resolution sensors, heavy digital processing, and are obstructed by the part and nozzle configuration, failing to provide comprehensive information on interlayer interfaces and physico-chemical states of deposited materials.

Innovation Solution

An additive manufacturing installation with thermal cameras positioned around the extrusion axis, capturing overlapping thermal fields to create a digital twin of the part, allowing real-time spatiotemporal temperature monitoring and defect detection, and enabling real-time adjustments to deposition parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermographic devices are used for non-destructive quality control, then defect detection capability is improved, but measurement precision deteriorates due to obstruction by part and nozzle configuration

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidtemperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The thermographic measurement system is divided into multiple independent thermal cameras, each capturing temperature data from specific zones. This segmentation allows each camera to focus on particular areas without obstruction, improving measurement precision while maintaining comprehensive defect detection capability across the entire deposition zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent positions thermal cameras in three-dimensional space around the extrusion axis at optimized distances and angles. By utilizing spatial dimensionality, the system captures thermal fields from multiple perspectives, overcoming obstructions caused by nozzle and part configuration, and enabling precise temperature measurement of interlayer interfaces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If high-resolution sensors are used for quality control, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using a single complex high-resolution sensor, the system employs multiple simpler thermal cameras positioned at different locations. Each camera captures temperature data from its specific field of view, and the combined data provides comprehensive high-resolution thermal mapping without requiring any single sensor to be overly complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The thermal cameras serve multiple functions: they monitor deposition temperature, detect defects, characterize interlayer interfaces, and provide data for digital twin creation. This multi-functionality reduces the need for separate specialized sensors, thereby simplifying the overall device complexity while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If comprehensive thermal monitoring is implemented, then quality control reliability is improved, but digital processing requirements increase

Engineering Contradiction:
Improvequality control reliabilityVSAvoiddigital processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system pre-establishes a digital twin model that incorporates expected thermal behavior patterns. During manufacturing, the actual thermal data from multiple cameras is compared against this pre-defined model, allowing for real-time quality assessment without requiring complex real-time processing of all raw data, thus improving reliability while managing processing complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a digital twin - a virtual copy of the physical manufacturing process and part geometry. This digital model serves as a reference for comparing actual thermal measurements, enabling automated defect detection and quality control with reduced processing complexity since the comparison is against a pre-computed model rather than requiring complex real-time analysis.

Inventive Principle:
Principle #26Copying

4Measurement precision

If multiple thermal cameras are positioned around the extrusion axis, then measurement precision is improved through overlapping fields, but device complexity increases

Engineering Contradiction:
Improvethermal field coverage accuracyVSAvoidcamera system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the fields of view of multiple thermal cameras to create overlapping coverage zones. By strategically positioning cameras so their fields overlap, the system achieves comprehensive thermal monitoring of the deposition area with enhanced measurement precision at overlap regions, while the combined data from all cameras provides complete spatial coverage without requiring an excessively complex multi-camera system.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables real-time, non-destructive quality control of additive manufacturing by providing detailed thermal data for interlayer interfaces and material states, reducing the need for heavy digital processing and improving defect detection accuracy.

Implementation Method 1

at least two thermal cameras linked to the reference frame of said extrusion nozzle and oriented around the extrusion axis of said nozzle

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP4384377B1Installation for additive manufacturing by depositing molten wire comprising an extrusion nozzle and a device for measuring and controlling the thermal process
Publication Date: 2025.09.03 COGIT COMPOSITES
  • EP4384377B1 patent drawingFigure 1
  • EP4384377B1 patent drawingFigure 2

AI summary

The invention discloses a fused filament additive manufacturing installation comprising an extrusion nozzle (6) for depositing a filament of material on a receiving surface supported by a plate that is mobile relative to said nozzle as well as a thermographic device, characterized in that said thermographic device is made up of at least two thermal cameras (10, 11) linked to the frame of reference of said extrusion nozzle (6) and oriented around the extrusion axis of said nozzle, the field of view of said thermal cameras (10, 11) being determined so as to cover a zone surrounding the extrusion axis with an intermediate zone in which the fields of view overlap, the installation further comprising a means whereby, for each of the cameras (10, 11), matrices of the historical sequences of temperature (x, y, z, tpure)i and relative position (X, Y, Z)i or (R, θ, Φ)¡ of a point of reference of said nozzle with respect to said plate or print support are recorded.