Dual-Laser Additive Manufacturing for In-Situ Machining

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Solution Overview

Problem

Additive-manufacturing processes like laser beam melting (LBM), selective laser melting (SLM), and selective laser sintering (SLS) face limitations in geometric precision and surface quality due to powder grain size and layer thickness, requiring additional rework operations like machining, which are time-consuming and costly, especially for internal surfaces.

Innovation Solution

A system and process combining two laser units, one for melting a powder bed and another for in-situ machining, using a continuous and pulsed laser source respectively, with a shared optical unit and movable guiding means to achieve precise layer formation and machining, allowing for selective machining of each layer to enhance geometric precision and surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If laser melting of powder bed is used for additive manufacturing, then material can be deposited layer by layer to form complex geometries, but geometric precision and surface quality are limited by powder grain size and layer thickness

Engineering Contradiction:

Improveability to manufacture complex geometriesVSAvoidgeometric precision and surface quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The manufacturing process is segmented into two distinct phases: a melting phase that deposits material layers, and a machining phase that removes excess material. This segmentation allows each phase to be optimized independently - the melting phase for geometric complexity and the machining phase for precision and surface quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The laser melting process performs a preliminary action by depositing material layers that form the basic geometry. Subsequently, a second laser performs preliminary machining on each layer before the next layer is deposited, ensuring precision is built into the structure during manufacturing rather than requiring extensive post-processing.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If rework operations like machining, sandblasting, or polishing are performed after additive manufacturing, then surface quality and precision can be improved, but production time and cost increase significantly

Engineering Contradiction:

Improvesurface qualityVSAvoidproduction time

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system maintains continuous useful action by alternating between melting and machining operations within the same manufacturing cycle. The second laser machines each layer immediately after it is formed, before the next layer is deposited, ensuring continuous progress without interruption for separate post-processing operations.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The additive manufacturing system performs its own machining operations using a second integrated laser unit. This self-service capability eliminates the need for separate post-processing operations and allows precision work to be done in-situ during the manufacturing process itself.

Inventive Principle:

Principle #25Self-service

3Device complexity

If a single laser unit is used for both melting and machining, then system complexity is reduced, but precision and functionality are compromised

Engineering Contradiction:

Improvesystem architectureVSAvoidmachining precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system achieves multi-functionality by integrating two laser units with different capabilities into a single additive manufacturing system. The first laser is optimized for melting powder bed material, while the second laser is optimized for precision machining. Both lasers share common optical components and control systems, reducing overall system complexity while maintaining high precision through specialized functionality.

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 improves geometric precision and surface quality by enabling in-situ machining of each layer, simplifying the system architecture and reducing the need for post-processing rework, while allowing for texturing and functionalization of parts with high precision.

Implementation Method 1

a first laser unit selectively emitting a first laser beam to form at least one layer of material by melting the powder bed

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

a second laser unit selectively emitting a second laser beam to machine at least a portion of said layer of material

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS11045907B2System and method for additively manufacturing by laser melting of a powder bed

Publication Date: 2021.06.29 MANUTECH USD

AI summary

A system of additive-manufacturing by laser melting of a powder bed. The system includes a first laser unit selectively emitting a first laser beam to form at least one layer of material by melting the powder bed; a second laser unit selectively emitting a second laser beam to machine at least a portion of the layer of material; and an optical unit enabling to focus the first laser beam on the powder bed to be melted and the second laser beam on the layer of material to be machined. The system is able to produce a part by successive stacking of melted then machined layers of material. A process of additive-manufacturing by laser melting of a powder bed is also contemplated.