Volume Support Scanning for Accurate Internal Holes in AM
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Solution Overview
Problem
Additive manufacturing techniques, such as powder bed fusion, face challenges in maintaining dimensional accuracy and preventing distortion of internal holes and cavities due to thermal stresses and inaccuracies, especially in high-performance materials like nickel- or cobalt-based superalloys, which often require costly and time-consuming post-processing.
Innovation Solution
A method involving a scanning strategy that selectively irradiates regions within holes or cavities with a lower rigidity supporting structure, characterized by increased porosity and tailored irradiation parameters like hatching distance and scanning speed, to provide volume support and prevent misalignment during buildup and thermal treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional selective laser melting is used to manufacture components with internal holes or cavities, then material economy and design freedom are improved, but dimensional accuracy and alignment of internal holes deteriorate due to thermal stresses and distortion
Solution Approach 1:
The patent applies preliminary action by generating supporting structures within internal holes and cavities before the additive manufacturing process is completed. These supporting structures are created in advance to prevent distortion and maintain dimensional accuracy during subsequent manufacturing steps and thermal treatment, thereby resolving the contradiction between design freedom and manufacturing precision
Solution Approach 2:
The patent utilizes parameter changes by selectively modifying irradiation parameters (such as laser power, scanning speed, and hatching distance) when generating supporting structures compared to regular component material. This allows the supporting structures to have different properties that enable them to counteract thermal stresses without compromising the final component quality, thus maintaining both design freedom and dimensional accuracy
2Manufacturing precision
If supporting structures are generated within holes and cavities using tailored irradiation parameters, then dimensional accuracy and alignment are improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing different irradiation parameters and scanning strategies specifically within hole and cavity regions compared to the rest of the component. The supporting structures are generated with localized properties (different hatching distance, scanning speed, or laser power) only where needed, rather than uniformly across the entire component, thus improving alignment without excessively increasing overall device complexity
Solution Approach 2:
The patent uses segmentation by dividing the manufacturing process into distinct regions: regular component areas with standard parameters and hole/cavity areas with tailored parameters for supporting structure generation. This segmentation allows the complex scanning strategy to be applied only where necessary, managing device complexity while achieving improved dimensional accuracy
3Ease of manufacture
If supporting structures with lower rigidity are generated in holes, then ease of post-processing is improved, but mechanical strength of the supporting structure deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting irradiation parameters (such as reduced laser power, increased scanning speed, or modified hatching distance) when generating supporting structures, resulting in material with lower rigidity and porosity. This enables easier post-processing and machining of the supporting structures while they still provide sufficient mechanical support during the additive manufacturing process to maintain dimensional accuracy
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 enhances the dimensional accuracy and reproducibility of components, reduces wastage, and simplifies post-processing by allowing easier machining of the supporting structure, thereby improving the efficiency and quality of additive manufacturing.
Implementation Method 1
A method of selective laser melting is described in EP 2 601 006 B1, for example
Implementation Method 2
The present invention relates to so-called powder bed fusion (PBF). Such PBF techniques comprise e.g. selective laser melting (SLM), selective laser sintering (SLS) or electron beam melting (EBM)
Implementation Method 3
The layer thickness is determined by a recoater that automatically distributes a required layer of a powdery material on a manufacturing plane and removes excess material from the build space
Implementation Method 4
dimensional accuracy and alignment of said hole(s)—possibly as compared to the aimed or target design—can be improved... mechanically counteracting stress and/or distortion during the additive buildup
Data Source
AI summary
A method of additive manufacturing includes a) providing a component geometry with a hole and, b) selectively irradiating a powder bed with an energy beam according to the geometry in a layerwise manner, wherein in layers of the component including the hole, the respective regions which define the hole are irradiated with the energy beam such that a supporting structure is generated in the hole having a lower rigidity than a structure of the component. The supporting structure is used for counteracting stress or distortion during the additive buildup. A computer program product and apparatus correspond to the method.