Thin Metal Additive Manufacturing With Thermal Shielding Base Layer
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Solution Overview
Problem
Existing additive manufacturing processes for thin metal alloy parts, particularly those less than 2 mm thick, face challenges such as deformation and high energy input requirements, which can lead to buckling and negative impacts on the microstructure, while also being time and cost-intensive.
Innovation Solution
A method involving low and high energy input deposition steps, with a base layer providing thermal shielding, using laser power, surface area, and feed rate to control deformation, and optionally incorporating a thermal martyr piece for heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high energy input deposition is used to rapidly form bosses on thin substrate parts, then productivity is improved, but the substrate part deforms and the microstructure is negatively impacted
Solution Approach 1:
The deposition process is divided into multiple passes with alternating low and high energy inputs. Low energy passes are interspersed between high energy passes to allow thermal relaxation and prevent excessive heat accumulation in the thin substrate, thereby reducing deformation while maintaining overall productivity through rapid high energy deposition phases.
Solution Approach 2:
The method employs periodic alternation between low energy input steps and high energy input steps during deposition. This periodic action allows the substrate to periodically cool and relax, preventing continuous thermal buildup that would cause deformation, while still achieving rapid material accumulation through the high energy phases.
2Loss of time
If high energy input deposition is used to reduce manufacturing time, then productivity is improved, but the heat-affected zone expands and impacts the substrate part
Solution Approach 1:
The continuous high energy deposition is segmented into discrete high energy input steps separated by low energy input steps. This segmentation allows heat to dissipate between deposition phases, limiting the expansion of the heat-affected zone while maintaining rapid overall deposition throughput.
Solution Approach 2:
Low energy input steps are performed preliminarily between high energy steps to prepare the substrate by allowing thermal relaxation before the next high energy deposition. This preliminary thermal management action prevents excessive heat accumulation and limits heat-affected zone expansion.
3Manufacturing precision
If low energy input deposition is used throughout the process, then substrate deformation is minimized, but manufacturing time increases significantly
Solution Approach 1:
The energy input level is dynamically adjusted during the deposition process, switching between low and high energy modes based on the deposition stage and thermal state of the substrate. This dynamic adjustment allows the process to optimize between deformation control and deposition rate, using low energy when thermal management is critical and high energy when rapid material accumulation is needed.
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
The method effectively limits deformation to less than 0.3 mm, reduces thermal impact, and allows rapid production of complex shapes on thin metal alloy parts without significant machining, maintaining microstructural integrity.
Implementation Method 1
If a laser is used to deliver the energy, these processes are called 'LMD' for Laser Metal Deposition
Implementation Method 2
the base layer naturally provides a shielding effect which mitigates the thermal impact of the high energy input on the substrate part
Implementation Method 3
a localized energy input which allows the material to be locally brought to the melting temperature
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a method for additive manufacturing by depositing material on a part forming a substrate (3), the part forming a substrate being made of a metal alloy, and the method comprising a step of deposition with low energy input, corresponding to a surface energy less than 400 J/mm², onto a predefined depositing surface, in order to form a base layer (1; 1a), and a step of deposition with high energy input, corresponding to a surface energy greater than 500 J/mm², by depositing a wire on the already formed base layer.