Multi-sensor quality inference and control for additive manufacturing processes

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Solution Overview

Problem

Existing additive manufacturing processes lack non-destructive methods for verifying the integrity and quality of parts, as conventional quality assurance testing often requires destruction of the part.

Innovation Solution

The method involves monitoring the temperature of build planes using optical temperature sensors, detecting phase changes, and calibrating sensors to adjust the heat supplied by the heat source, allowing for real-time quality control without destroying the part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional quality assurance testing is used, then part integrity can be verified, but the part must be destroyed

Engineering Contradiction:
Improvepart integrity verificationVSAvoidpart destruction
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces mechanical/physical destruction with optical sensing. Multiple optical sensors (pyrometers, cameras) detect thermal radiation and light emissions during the additive manufacturing process to infer material phase changes, temperature distribution, and potential defects without contacting or destroying the part.

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

Solution Approach 2:

The patent introduces thermal radiation and light emission as intermediary signals between the material being processed and the sensors. These electromagnetic emissions serve as carriers of information about the material state, allowing indirect observation of phase changes and quality characteristics without direct physical interaction.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple optical sensors are used to monitor temperature, then measurement accuracy improves, but system complexity increases

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

Solution Approach 1:

The patent divides the monitoring task across multiple specialized sensors, each optimized for specific wavelength ranges or measurement functions. This segmentation allows each sensor to excel at its specific function while the collective system achieves comprehensive temperature and phase change monitoring capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs the sensor system to perform multiple functions: temperature measurement, phase change detection, and quality assessment. By making the optical sensing system multi-functional, the patent reduces the need for separate specialized devices and simplifies the overall system architecture.

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

3Reliability

If real-time temperature monitoring is implemented, then quality control improves, but processing time increases

Engineering Contradiction:
Improvequality controlVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements continuous optical monitoring throughout the additive manufacturing process without interrupting the build operations. Sensors continuously capture thermal radiation and light emissions, enabling real-time quality assessment that occurs simultaneously with material deposition and heating, eliminating separate inspection time.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent establishes a feedback loop where sensor data is processed and used to adjust process parameters in real-time. This closed-loop control enables dynamic quality management that prevents defects rather than detecting them after the fact, maintaining high quality standards without requiring additional processing time for post-inspection corrections.

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 approach enables non-destructive verification of part integrity, improving the efficiency and reliability of additive manufacturing by allowing for real-time adjustments and quality assessments.

Implementation Method 1

monitoring the temperature of a first portion of a build plane during an additive manufacturing operation with a first optical temperature sensor

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

the heat source melts the incrementally added powder by welding regions of the powder layer creating a moving molten region

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

detecting a change in state of material within the first portion as a heat source passes through the first portion of the build plane

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP3221076B1Multi-sensor quality inference and control for additive manufacturing processes
Publication Date: 2025.04.02 SIGMA LABS INC
  • EP3221076B1 patent drawingFigure 1
  • EP3221076B1 patent drawingFigure 2
  • EP3221076B1 patent drawingFigure 3A

AI summary

This invention teaches a multi-sensor quality inference system for additive manufacturing. This invention still further teaches a quality system that is capable of discerning and addressing three quality issues: i) process anomalies, or extreme unpredictable events uncorrelated to process inputs; ii) process variations, or difference between desired process parameters and actual operating conditions; and iii) material structure and properties, or the quality of the resultant material created by the Additive Manufacturing process. This invention further teaches experimental observations of the Additive Manufacturing process made only in a Lagrangian frame of reference. This invention even further teaches the use of the gathered sensor data to evaluate and control additive manufacturing operations in real time.