Additive Manufacturing Thermal Camera Calibration

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Solution Overview

Problem

Inaccurate temperature measurements in additive manufacturing systems can lead to poor cohesion between layers and structurally unsound builds due to temperature variations, which can be exacerbated by calibration drift and equipment issues such as dust accumulation and electrical noise, affecting build quality and reliability.

Innovation Solution

A method for calibrating non-contact temperature measurement devices by comparing temperature readings from a reference element with known emissivity to thermal camera data, using a controller to adjust readings and apply pixel-specific calibration factors, ensuring accurate temperature measurement without melting the build material, and performing calibration prior to and during the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If non-contact temperature measurement devices are used to monitor build material heating, then temperature control for layer fusion is improved, but measurement accuracy deteriorates due to calibration drift and equipment issues

Engineering Contradiction:
Improvetemperature controlVSAvoidtemperature measurement accuracy
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration of the thermal camera using a reference element with known emissivity before actual manufacturing. This preliminary action establishes accurate temperature measurements by comparing reference readings with camera readings, creating a baseline for subsequent measurements and preventing calibration drift from affecting build quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors temperature using the calibrated thermal camera and compares readings against expected temperature profiles during manufacturing. When deviations are detected, the system provides feedback to adjust heating parameters or alert operators, maintaining measurement accuracy throughout the manufacturing process.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If continuous calibration is performed during manufacturing, then measurement accuracy is maintained, but manufacturing time increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidmanufacturing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs comprehensive calibration before manufacturing begins, establishing accurate temperature measurement baselines. This preliminary calibration reduces the need for frequent interruptions during manufacturing, as the system can operate with established calibration data for extended periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of continuous calibration that would halt production, the system performs calibration periodically at predetermined intervals or when specific conditions are met (e.g., after a certain number of builds or when temperature drift thresholds are exceeded). This periodic approach maintains accuracy while minimizing impact on manufacturing throughput.

Inventive Principle:
Principle #19Periodic action

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 improves thermal measurement accuracy, reduces build quality issues, and maintains reliability by providing continuous calibration, ensuring accurate temperature control and improved build quality throughout the manufacturing process.

Implementation Method 1

controlling a radiation source to heat a reference element

Methodology Applied
Scientific EffectRadiation heating: Radiation

Implementation Method 2

obtaining a temperature profile of the reference element using a non-contact temperature measurement device

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentEP3433590B1Temperature measurement calibration in an additive manufacturing system
Publication Date: 2023.02.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3433590B1 patent drawingFigure 1~2
  • EP3433590B1 patent drawingFigure 3~4
  • EP3433590B1 patent drawingFigure 5~6

AI summary

Examples of temperature measurement calibration in an additive manufacturing system are described. In one case, a method of calibrating a non-contact temperature measurement device involves applying energy from a radiation source of the additive manufacturing system to heat a reference element. The reference element is thermally coupled to a temperature sensor. A temperature reading from the temperature sensor is compared with data from the non-contact temperature measurement device to calibrate the device.