3D Printing Laser Focus Calibration at the Build Plane

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Solution Overview

Problem

Existing 3D printing systems face challenges in properly converging an energy beam at the build plane during the layer-by-layer fabrication of three-dimensional articles using powdered materials, affecting productivity and uniformity.

Innovation Solution

A method and apparatus that calibrate the convergence of a radiation beam by analyzing acoustic signals generated when the beam impinges on a metal platen within the build chamber, adjusting the platen's position to achieve optimal laser convergence at the build plane height, using a controller to coordinate the movement mechanism, laser system, and acoustic sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple energy beams are utilized to increase productivity, then the output per unit time is improved, but the difficulty of properly converging each beam at the build plane increases

Engineering Contradiction:
Improveoutput per unit timeVSAvoidbeam convergence accuracy
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses acoustic sensors to detect signals generated during material consolidation and feeds this information back to determine optimal beam convergence. The controller adjusts beam parameters based on acoustic feedback to achieve precise convergence at the build plane, resolving the difficulty of maintaining accuracy across multiple beams.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces traditional mechanical or optical alignment methods with acoustic field-based convergence determination. Acoustic sensors detect consolidation signals to non-invasively identify optimal beam focus points, substituting complex mechanical adjustment systems with acoustic measurement and control.

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

2Measurement precision

If acoustic sensing is used to determine beam convergence, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improvebeam convergence measurement accuracyVSAvoidsystem component count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The acoustic sensing system serves multiple functions: it monitors material consolidation quality, determines beam convergence accuracy, and provides feedback for real-time adjustment. This multi-functionality justifies the added complexity by eliminating the need for separate measurement and control systems.

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

Solution Approach 2:

The system uses the acoustic signals naturally generated during the printing process itself to determine convergence, rather than requiring separate calibration procedures or additional measurement equipment. The printing process generates the measurement signals it needs, making the system self-calibrating.

Inventive Principle:
Principle #25Self-service

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 ensures precise convergence of the energy beam, improving the accuracy and uniformity of the 3D printing process, enabling higher productivity and better layer formation in the fabrication of three-dimensional articles.

Implementation Method 1

analyzing a signal from an acoustic sensor positioned within the build chamber... determining a height of maximum laser convergence for the platen

Methodology Applied
Scientific EffectAcoustic signal generation: Acoustic Emission

Implementation Method 2

operating a laser system to impinge a radiation beam upon the upper surface of the platen

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP3875250B1Three-dimensional printing system with laser convergence calibration based upon acoustic analysis
Publication Date: 2023.01.11 LAYERWISE
  • EP3875250B1 patent drawingFigure 1~2
  • EP3875250B1 patent drawingFigure 3~4
  • EP3875250B1 patent drawingFigure 5

AI summary

A method of manufacturing a three-dimensional article includes: (1) Loading a metal platen into a build chamber, the metal platen defines an upper surface; (2) Performing concurrent processes including operating a movement mechanism to vertically translate the platen, operating a laser system to impinge a radiation beam upon the upper surface of the platen, and receiving a signal from an acoustic sensor that is positioned within the build chamber; (3) Analyzing the signal including determining a height of optimal laser convergence for the platen; and (4) Based upon the analysis, adjusting the laser convergence height to a build plane height.