Laser Beam Profiling With Retroreflectors During Powder Bed Scanning

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for determining the beam profile of a laser beam in a processing machine are time-consuming and require significant setup and measurement time, as they typically involve external measuring devices that cannot be used during operation due to space constraints and accessibility issues within the processing chamber.

Innovation Solution

Incorporating a retroreflector in the processing field, which reflects a significant portion of the laser radiation back to the scanner device, allowing for the determination of the beam profile during operation by scanning the retroreflector with the laser beam, thereby increasing detection precision and reducing measurement time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external measuring devices are used to determine the beam profile, then measurement precision can be achieved, but the measurement time increases significantly and the processing machine must be stopped

Engineering Contradiction:
Improvebeam profile determination precisionVSAvoidsetup and measurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The retroreflector enables the laser beam itself to serve as the measurement probe by reflecting a portion of its own radiation back to the detector. This self-service approach eliminates the need for external measuring devices and allows continuous measurement during operation, resolving the contradiction between measurement precision and time loss.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retroreflector acts as an intermediary element that couples the laser beam with the detector system. It reflects a controlled portion of the laser radiation back to the scanner device where the detector is located, enabling indirect measurement without requiring external devices or stopping the processing machine.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If external measuring devices are introduced into the processing chamber, then beam profile can be measured, but the device complexity and installation space requirements increase

Engineering Contradiction:
Improvebeam profile determination precisionVSAvoidmeasuring device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The laser beam serves its dual function as both the processing tool and the measurement probe. By using the laser beam's own radiation reflected by the retroreflector, the system eliminates complex external measuring devices, reducing overall device complexity while maintaining measurement capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retroreflector serves multiple functions: it acts as a beam profile measurement target, a radiation source for the detector, and a non-intrusive element that can be integrated into the existing processing chamber without adding significant complexity. This multi-functionality resolves the contradiction between measurement capability and device complexity.

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

3Measurement precision

If the processing machine is stopped for measurement, then accurate beam profile determination is possible, but productivity decreases

Engineering Contradiction:
Improvebeam profile determination precisionVSAvoidproduction efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The measurement process continues uninterrupted during normal processing operations. The retroreflector enables continuous beam profile monitoring without stopping the laser processing or powder bed preparation, maintaining the continuity of useful action and eliminating productivity loss associated with measurement interruptions.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs self-diagnosis by using the laser beam's own radiation reflected from the retroreflector. This self-service measurement capability allows the processing machine to monitor its beam profile continuously without external intervention or production stoppage, resolving the contradiction between measurement accuracy and productivity.

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

Enables quick and precise determination of the beam profile, allowing for stable and reproducible machining processes without interrupting the production of three-dimensional components, as the beam profile can be determined within minutes or seconds, improving operational efficiency and reducing setup time.

Implementation Method 1

arranging at least one retroreflector (19) in the processing field (13) of the scanner device (11)

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

detecting laser radiation (20) which is emitted when scanning over the retroreflector (19) is reflected back into the scanner device (11)

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3538299B1Method for determining a beam profile of a laser beam, and processing machine with retroreflectors
Publication Date: 2021.10.13 TRUMPF LASER & SYSTEMTECHNIK GMBH
  • EP3538299B1 patent drawingFigure 1
  • EP3538299B1 patent drawingFigure 2a~3

AI summary

The invention relates to a method for determining a beam profile of a laser beam (6), which is positioned by means of a scanner device (11) in a processing field (13), comprising: arranging at least one retroreflector (19) in the processing field (13) of the scanner device (11), which area is preferably formed in a processing chamber (15) for irradiating powder layers (3), detecting laser radiation (20) which, during scanning travel over the retroreflector (19) with the laser beam (6), is reflected back into the scanner device (11), and determining the beam profile of the laser beam (6) by using the laser radiation (20) detected during the scanning travel over the retroreflector (19). The invention further relates to an associated processing machine (1) for producing three-dimensional components (2) by means of the irradiation of powder layers (3).