Thin-Wall Additive Building with Two-Step Defect Remelting
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Solution Overview
Problem
Existing additive layer building processes face challenges in producing thin wall regions with adequate mechanical properties due to thermal conduction effects, leading to increased defects and inadequate sealing in components like abradable seals for turbomachines.
Innovation Solution
A layer building process involving a first solidifying step with low energy input to create a defect-affected wall region, followed by a second solidifying step with adjusted irradiation parameters to remelt and heal defects, without additional powder application, allowing for the production of thin walls with improved mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single laser track or electron beam track is used to produce thin wall regions, then the wall thickness can be minimized, but thermal conduction effects cause the cure width to exceed the focal diameter, resulting in increased energy input and potential defects
Solution Approach 1:
The single solidifying step is divided into two sequential solidifying steps. The first step creates the initial wall structure with minimal energy input, while the second step remelts and heals defects without adding significant thickness. This segmentation allows precise control of the final wall dimensions while improving quality.
Solution Approach 2:
The first solidifying step performs the preliminary action of creating the wall structure with controlled energy input to minimize thermal conduction effects. The second step then performs the corrective action of remelting and healing defects, achieving both thin wall thickness and high manufacturing precision.
2Length of moving object
If low energy input and high exposure speed are used to minimize track width and energy input, then the wall thickness can be reduced, but the number of defects (particularly fusion defects) increases
Solution Approach 1:
The solidifying process is segmented into two steps: the first step uses low energy input to create the wall structure with minimal thermal conduction, while the second step applies targeted energy to remelt and heal defects. This segmentation allows the process to benefit from both low energy input and high reliability.
Solution Approach 2:
The first solidifying step intentionally allows for the formation of defects at low energy input, which are then converted into an opportunity for improvement in the second step. The second step remelts the defect-affected regions, transforming the harmful defects into healed, high-quality wall structures.
3Manufacturing precision
If additional powder application is performed between solidifying steps, then material can be added to compensate for defects, but the wall thickness increases and the process complexity increases
Solution Approach 1:
The first solidifying step performs the preliminary action of creating the wall structure with controlled energy input to minimize thermal conduction effects. The second step then performs the corrective action of remelting and healing defects, achieving both thin wall thickness and high manufacturing precision.
Solution Approach 2:
The energy input parameters are changed between the two solidifying steps. The first step uses lower energy input to minimize thermal conduction and create the initial structure, while the second step uses adjusted energy parameters to remelt and heal defects without significantly increasing wall thickness.
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 method enables the production of very thin walls with high mechanical stability by healing defects in the first solidifying step, ensuring a high sealing effect and reduced risk of damage in abradable seals.
Implementation Method 1
In selective laser melting, thin layers of the material or materials used are applied to a building platform and are melted and solidified locally in a building-up and joining zone with the use of one laser beam or a plurality of laser beams
Implementation Method 2
As a rule, owing to thermal conduction effects, the cure width (cure zone) even amounts to somewhat more than the focal diameter or the track width
Implementation Method 3
the material is selectively irradiated with at least one energy beam, wherein irradiation parameters of the at least one energy beam are set in such a way that a molten bath with a molten bath diameter that is at least 25% of a wall thickness that is to be manufactured, is produced
Data Source
AI summary
The invention relates to a layer building process for the additive manufacture of at least one wall region of a component including applying at least one powder layer of a material to at least one building-up and joining zone of at least one movable building platform, carrying out a first solidifying step, in which the material is irradiated selectively with at least one energy beam, wherein irradiation parameters of the at least one energy beam are set so a molten bath is produced and a defect-affected wall region of the wall is produced, without applying a further powder layer, carrying out a second solidifying step, in which the defect-affected wall region produced in the first solidifying step is irradiated selectively with the at least one energy beam, lowering the building platform layer by layer by a predefined layer thickness, and repeating the steps above one or more times.