Multi-Laser Melt Pool Monitoring for Laser Pointing Calibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In Direct Metal Laser Melting (DMLM) systems with multiple laser devices, ensuring accurate laser pointing is crucial for producing defect-free components, but existing systems lack effective methods for real-time monitoring and calibration of laser positions, leading to potential manufacturing defects.

Innovation Solution

An additive manufacturing system with an optical system that detects the position of laser beams in the melt pool and calibrates them using a controller to direct the lasers to the correct positions, incorporating a plurality of laser devices, scanning devices, and an optical system to monitor and adjust the laser beams' positions in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple laser devices are used to increase manufacturing speed, then productivity is improved, but laser pointing accuracy deteriorates due to difficulty in monitoring and calibrating multiple laser positions

Engineering Contradiction:
Improvemanufacturing speedVSAvoidlaser pointing accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where an optical system continuously monitors the actual position of each laser beam on the build platform. The controller receives this position information and automatically adjusts laser pointing parameters to correct deviations from target positions. This closed-loop feedback system maintains laser accuracy despite using multiple lasers for high-speed manufacturing.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical calibration methods with an optical detection and automated control system. Instead of physically adjusting laser mounts through trial and error, the system uses optical sensors to detect beam positions and electronically controls laser pointing parameters, enabling precise calibration of multiple lasers without manual intervention.

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

2Manufacturing precision

If real-time monitoring and calibration systems are implemented, then laser positioning accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelaser positioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The optical system serves multiple functions: it monitors laser beam positions, detects deviations from target locations, and provides data for controller adjustments. This multi-functional approach consolidates what could be separate complex subsystems into a unified optical monitoring and control platform, reducing overall system complexity while maintaining high positioning accuracy.

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

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 solution improves the accuracy and precision of the laser beams, reducing defects in the manufactured components by ensuring accurate positioning of the melt pools, thereby enhancing the overall manufacturing process efficiency and quality.

Implementation Method 1

an optical system to detect the position of each laser beam in the melt pool

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentEP3351323B1Additive manufacturing apparatus with systems of in-build assessment and correction of laser pointing accuracy for multiple-laser apparatus
Publication Date: 2021.11.03 GENERAL ELECTRIC CO
  • EP3351323B1 patent drawingFigure 1
  • EP3351323B1 patent drawingFigure 2
  • EP3351323B1 patent drawingFigure 3

AI summary

An additive manufacturing system (10) includes a plurality of laser devices (14, 15), a plurality of first scanning devices (18, 19), and an optical system (20). The optical system (20) includes an optical detector (38) and a second scanning device (42). The plurality of laser devices (14, 15) are each configured to generate a laser beam (16, 17). The plurality of first scanning devices (18, 19) is each configured to selectively direct the laser beam (16, 17) from a laser device (14, 15) of the plurality of laser devices (14, 15) across a powder bed (27). The laser beam (16, 17) generates a melt pool (22) in the powder bed (27). The optical detector (38) is configured to detect electromagnetic radiation generated by the melt pool (22). The second scanning device (42) is configured to direct electromagnetic radiation generated by the melt pool (22) to the optical detector (38). The optical system (20) is configured to detect a position of the laser beams (16, 17) in the melt pool (22).