3D Printer Calibration via Interference Patterns

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Solution Overview

Problem

Existing calibration methods for devices producing three-dimensional objects by layer-by-layer solidification of building materials have limited accuracy, which can lead to inaccuracies in positioning and orientation, affecting the precision of delicate structures and overall dimensional accuracy.

Innovation Solution

A method involving the generation of substantially periodic modulation patterns in overlapping areas of a construction field, with detection and adjustment of the overlay pattern's position relative to a reference, using electromagnetic radiation or particle beams, to achieve precise calibration and correction of deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple laser beams are used with overlapping sub-areas, then the construction field coverage is improved, but the positioning accuracy deteriorates due to alignment deviations between beams

Engineering Contradiction:
Improveconstruction field coverageVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical alignment methods with optical interference patterns. By using electromagnetic radiation to create interference patterns in the overlap zones, the system achieves sub-micrometer positioning accuracy without relying on mechanical alignment of multiple laser beams, thus resolving the contradiction between coverage and precision

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

Solution Approach 2:

The patent introduces interference patterns as an intermediary measurement mechanism. These patterns serve as a mediator that translates the relative positions of multiple laser beams into measurable optical signals, enabling precise calibration of beam alignments and eliminating direct mechanical positioning errors

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If calibration is performed before actual construction, then the setup time is reduced, but the calibration accuracy is limited by the simplicity of test patterns

Engineering Contradiction:
Improvecalibration setup timeVSAvoidcalibration accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of the calibration pattern from simple geometric shapes to complex interference patterns with varying spatial frequencies. This transformation enables much higher measurement precision while maintaining the same calibration timing, as the interference patterns provide richer positional information for accurate beam alignment measurement

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If simple test patterns are used for calibration, then the detection process is simplified, but the measurement resolution is insufficient for delicate structures

Engineering Contradiction:
Improvedetection simplicityVSAvoidposition measurement resolution
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs periodic interference patterns with specific spatial frequencies to create measurable variations in the overlap zones. These periodic patterns provide high-contrast, easily detectable signals that maintain detection simplicity while achieving sub-micrometer measurement resolution, thus resolving the contradiction between ease of detection and measurement precision

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 enables high-dimensional accuracy and the production of delicate three-dimensional objects by correcting positional deviations, ensuring precise solidification and maintaining accuracy throughout the manufacturing process.

Implementation Method 1

a solidification device for radiating beams of electromagnetic radiation or particle beams onto selective locations of the construction field

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

producing a three-dimensional object by selectively solidifying building material layer by layer

Methodology Applied
Scientific EffectSelective solidification: Melting

Implementation Method 3

The first modulation pattern and the second modulation pattern form a substantially periodic overlay pattern in the overlap zone

Methodology Applied
Scientific EffectInterference pattern: Interference

Data Source

PatentEP3771551B1Method for calibrating a device for generating a three-dimensional object and calibration unit
Publication Date: 2024.02.07 EOS GMBH ELECTRO OPTICAL SYST
  • EP3771551B1 patent drawingFigure 1
  • EP3771551B1 patent drawingFigure 2
  • EP3771551B1 patent drawingFigure 3A~3B

AI summary

Method for calibrating a device (1) for producing a three-dimensional object (2) by layer-by-layer selective solidification of build material (15) comprising the step of generating a substantially periodic first modulation pattern (101) in a first sub-area (100) of a build area (8), the step of generating a substantially periodic second modulation pattern (201) in a second sub-area (200) of the build area (8), wherein the first modulation pattern (101) and the second modulation pattern (201) form a substantially periodic superposition pattern (301) in the overlap zone (300), the period of which is greater than the period of the first modulation pattern (101) and the period of the second modulation pattern (201), the step of detecting the superposition pattern (301), and the step of determining the deviation of the position of the superposition pattern (301) on the build area (8) from a reference position.