Dual Deflection Laser Scanning for Additive Manufacturing

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Solution Overview

Problem

Existing methods for producing three-dimensional workpieces using additive layer construction methods are inefficient in terms of process time, as they require extended periods to solidify large areas or volumes of raw material, leading to increased production time without ensuring the quality of the workpiece.

Innovation Solution

A method utilizing a combination of a first deflection unit and a second deflection unit to control a laser beam, where the second deflection unit can accelerate the laser beam movement significantly more than the first, allowing for the creation of multiple molten pools and efficient movement between them without forming a molten pool in the gap, thereby optimizing the solidification process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single laser beam is used to solidify raw material layer by layer, then the manufacturing precision and quality of the workpiece are maintained, but the production time increases significantly when building large volumes

Engineering Contradiction:
Improveworkpiece qualityVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent divides the laser beam path control into two independent deflection units: a first deflection unit (scanner) for coarse positioning and a second deflection unit for fine positioning and high-speed movement. This segmentation allows the system to maintain precision while reducing travel time across large build volumes, directly resolving the contradiction between workpiece quality and production time.

Inventive Principle:
Principle #1Segmentation

2Volume of stationary object

If the laser beam travels long distances across large build volumes, then larger workpieces can be produced, but the process time increases due to longer beam travel distances

Engineering Contradiction:
Improvebuild volumeVSAvoidprocess time
Core Design Contradiction:
Volume of stationary objectVSLoss of time

Solution Approach 1:

The patent replaces the traditional single mechanical scanner with a hybrid system combining a mechanical scanner (first deflection unit) and a faster deflection unit (second deflection unit). This substitution enables high-speed beam repositioning without compromising the ability to cover large build volumes, thus reducing process time while maintaining large build capacity.

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

3Productivity

If the laser beam moves quickly across the raw material to reduce process time, then productivity increases, but the precision of solidification and workpiece quality deteriorates

Engineering Contradiction:
Improveprocess speedVSAvoidsolidification precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the beam deflection function into two units: the first deflection unit handles coarse positioning with adequate precision, while the second deflection unit provides fine positioning adjustments and high-speed corrections. This segmentation enables the system to move the beam quickly across large distances while maintaining precise positioning at the destination, thus increasing productivity without sacrificing solidification precision.

Inventive Principle:
Principle #1Segmentation

4Productivity

If multiple beam sources are used to solidify larger areas simultaneously, then productivity increases, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvesolidification rateVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent makes a single laser beam multi-functional by using two deflection units, allowing it to perform both coarse scanning and fine positioning tasks that would traditionally require multiple beam sources or complex optical systems. This approach achieves high productivity through rapid beam repositioning rather than through parallel beams, thereby avoiding the increased device complexity and cost associated with multiple beam sources.

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 approach enables faster and more precise production of three-dimensional workpieces by maintaining multiple molten pools continuously and moving the laser beam between them with high acceleration, allowing for quicker solidification of larger areas without compromising quality.

Implementation Method 1

irradiating a raw material layer with a laser beam, whereby a melt pool is created at the point where the laser beam strikes the raw material layer

Methodology Applied
Scientific EffectLaser radiation heating: Laser

Implementation Method 2

a melt pool is created at the point where the laser beam strikes the raw material layer

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

changing the position of the laser beam on the raw material layer using a first deflection unit

Methodology Applied
Scientific EffectOptical deflection: Reflection

Implementation Method 4

changing the position of the laser beam on the raw material layer using a second deflection unit. The second deflection unit is configured to deflect the position of the laser beam with a greater acceleration

Methodology Applied
Scientific EffectOptical deflection: Reflection

Implementation Method 5

solidify it by site-specific irradiation (e.g., by fusing or sintering) to ultimately obtain a workpiece of the desired shape

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3866999B1Method and device for producing a three-dimensional workpiece
Publication Date: 2023.03.15 NIKON SLM SOLUTIONS AG
  • EP3866999B1 patent drawingFigure 1
  • EP3866999B1 patent drawingFigure 2
  • EP3866999B1 patent drawingFigure 3

AI summary

The invention relates to a method for producing a three-dimensional workpiece. The method comprises irradiating a raw material layer with a laser beam, wherein a melt bath is produced at a point at which the laser beam impinges on the raw material layer, changing a position of the laser beam on the raw material layer with the aid of a first diverting unit and changing the position of the laser beam on the raw material layer with the aid of a second diverting unit. The second diverting unit is designed to divert the position of the laser beam with a greater acceleration than a maximum possible acceleration of a diversion by the first diverting unit. The invention also relates to a device for producing a three-dimensional workpiece.