Multi-Sensor Quality Inference for Real-Time Additive Manufacturing Control

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Solution Overview

Problem

Current additive manufacturing processes face challenges in non-destructively verifying the quality of parts, as conventional quality assurance methods often require destruction of the part and cannot be applied to production parts, and there is a need for real-time monitoring and control to manage variations in the size and temperature of the weld pool during the manufacturing process.

Innovation Solution

The method involves using optical temperature sensors to monitor temperature changes and calibrate heat supply based on sensor data, allowing for real-time adjustments to maintain consistent weld pool size and temperature, and combining Lagrangian and Eulerian reference frames to predict process parameters and ensure quality control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional quality assurance testing is used to verify part quality, then thorough inspection of internal portions is achieved, but the part must be destroyed

Engineering Contradiction:
Improvequality verification accuracyVSAvoidpart integrity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces physical contact-based destructive testing with non-contact optical sensing systems. Multiple optical sensors (pyrometers, cameras, interferometers) detect thermal radiation, light reflection, and interference patterns to infer internal part quality without mechanical contact or destruction, resolving the contradiction between thorough inspection and part preservation

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

Solution Approach 2:

The patent introduces optical sensors as intermediary devices that indirectly measure internal part characteristics through thermal radiation and light interactions. These sensors act as mediators between the part and the inspection system, enabling quality verification without direct physical contact that would require destruction

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If real-time temperature monitoring is implemented with multiple sensors, then weld pool consistency is improved, but system complexity increases

Engineering Contradiction:
Improveweld pool temperature consistencyVSAvoidsensor system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the monitoring system into multiple specialized optical sensors, each targeting specific parameters (temperature, weld pool geometry, thermal radiation). This segmentation allows each sensor to be optimized for its specific function while collectively providing comprehensive process control, managing complexity through functional specialization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs optical sensors that serve multiple functions simultaneously - measuring temperature, weld pool size, and thermal characteristics with the same hardware platform. This multi-functionality reduces overall system complexity compared to using separate specialized devices for each measurement type

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

3Reliability

If non-contact optical sensing is used to monitor temperature, then part integrity is maintained, but measurement precision at high temperatures becomes challenging

Engineering Contradiction:
Improvepart integrityVSAvoidhigh temperature measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent utilizes the change in thermal radiation parameters with temperature to enable non-contact measurement. By detecting variations in radiation intensity, spectral distribution, and temporal patterns, the system accurately measures high temperatures without contact, maintaining both part integrity and measurement precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies pyrometric principles that detect color changes in thermal radiation corresponding to temperature variations. Optical sensors measure the spectral characteristics of emitted radiation, where color temperature changes provide accurate high-temperature measurements without physical contact

Inventive Principle:
Principle #32Color 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

This approach enables non-destructive quality verification and real-time process control, improving the consistency and integrity of additive manufactured parts by adjusting heat input based on sensor data, thereby enhancing the precision and reliability of the additive manufacturing process.

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

using an energy source that takes the form of a moving region of intense thermal energy

Methodology Applied
Scientific EffectThermal energy transfer: Conduction (thermal)

Implementation Method 4

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

PatentUS11931956B2Multi-sensor quality inference and control for additive manufacturing processes
Publication Date: 2024.03.19 DIVERGENT TECHNOLOGIES INC
  • US11931956B2 patent drawing
  • US11931956B2 patent drawing
  • US11931956B2 patent drawing

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.