Irradiation Vector Definition for Additive Manufacturing Downskin Regions

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Solution Overview

Problem

In additive manufacturing, particularly in powder bed fusion techniques like selective laser sintering and selective laser melting, the challenge is to prevent overheating and internal stress in downskin regions due to inadequate heat transfer, leading to deformation and instability in the building process.

Innovation Solution

A method is introduced to define irradiation vectors with a minimum length of 1 mm or more that extend into both downskin and volume regions, using distinct irradiation parameters to ensure stable heat management and prevent short vectors, which would otherwise cause overheating and instability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If separate hatching is applied to downskin region and volume region with different irradiation parameters, then overheating in downskin regions is reduced, but irradiation vectors become too short leading to inadequate cooling time and process instability

Engineering Contradiction:

Improvetemperature control in downskin regionsVSAvoidbuilding process stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The layer is divided into downskin region and volume region with separate hatching patterns. Downskin vectors are defined to extend into the volume region, creating a segmented approach where different irradiation parameters can be applied to different regions while ensuring minimum vector length of 1mm for stable cooling cycles

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different irradiation parameters are assigned locally to downskin vectors versus volume vectors. Downskin vectors use reduced irradiation power to prevent overheating, while volume vectors use standard parameters. This local differentiation allows temperature control in critical areas without compromising overall process stability

Inventive Principle:

Principle #3Local quality

2Stress or pressure

If irradiation power is reduced in downskin regions, then internal stress and deformation are minimized, but vector length becomes too short causing overheating and unstable building process

Engineering Contradiction:

Improveinternal stress in downskin regionsVSAvoidcooling time between vectors

Core Design Contradiction:

Stress or pressureVSTemperature

Solution Approach 1:

The hatching pattern dynamically adapts to the geometry of downskin regions. Vectors in downskin areas are extended to minimum length of 1mm and may change direction or merge with adjacent vectors to ensure adequate length while maintaining reduced irradiation power for stress control

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Irradiation parameters are changed based on vector location and length. Downskin vectors have reduced power but minimum 1mm length, while volume vectors use standard parameters. This parameter differentiation allows stress reduction in downskin regions while maintaining adequate cooling time through enforced minimum vector length

Inventive Principle:

Principle #35Parameter changes

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 effectively prevents overheating and deformation by ensuring adequate cooling time between irradiation vectors, stabilizing the building process and improving the quality of three-dimensional workpieces with complex geometries.

Implementation Method 1

a raw material powder layer is applied onto a carrier and subjected to radiation (e.g., laser or particle radiation) in a site-selective manner... The radiation penetrating into the powder layer causes heating and consequently melting or sintering of the raw material powder particles

Methodology Applied

Scientific EffectLaser radiation heating: Laser

Implementation Method 2

Examples for powder bed fusion techniques include selective laser melting and selective laser sintering

Methodology Applied

Scientific EffectSelective laser melting:

Implementation Method 3

Examples for powder bed fusion techniques include selective laser melting and selective laser sintering

Methodology Applied

Scientific EffectSelective laser sintering:

Implementation Method 4

The at least one of the first irradiation vectors has a length of 1 mm or more... The resulting overheating may lead, e.g., to a problem of an unstable building process

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20240399460A1Technique for defining a plurality of irradiation vectors

Publication Date: 2024.12.05 NIKON SLM SOLUTIONS AG

AI summary

A method for defining a plurality of irradiation vectors for an apparatus for producing a three-dimensional work piece via additive manufacturing is provided. The method comprises, for a layer of a three-dimensional work piece to be generated, defining a downskin region in the layer, and defining a set of first irradiation vectors covering the downskin region. At least one of the first irradiation vectors extends into a volume region of the layer, adjacent to the downskin region. The at least one of the first irradiation vectors has a length of 1 mm or more. The method further comprises defining a set of second irradiation vectors covering a remaining part of the volume region of the layer, assigning a first set of irradiation parameters to the set of first irradiation vectors, and assigning a second set of irradiation parameters to the set of second irradiation vectors, the second set of irradiation parameters being different from the first set.