Pre-Bent Substrate Mounting for DED Distortion Mitigation
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Solution Overview
Problem
Conventional additive manufacturing methods like Directed Energy Deposition (DED) for titanium and titanium alloys face significant challenges with residual stress and distortion due to thermal cycling, leading to unwanted deformation, warping, and potential failure, which existing stress relief methods like peening and rolling are inefficient and costly.
Innovation Solution
A method and system that includes pre-bending and pre-heating a metallic substrate, using a mount system with controlled heat transfer and inert atmosphere, and employing a gas jet device to minimize residual stress and distortion during DED, ensuring geometrically accurate and durable metal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional DED manufacturing is used, then productivity and fabrication freedom are improved, but residual stress and distortion increase leading to tolerance loss
Solution Approach 1:
The substrate is pre-bent to a predetermined reverse curvature before DED manufacturing begins. This preliminary action creates a counter-curvature that compensates for the expected thermal distortion, allowing the final product to achieve the desired flat or curved geometry without post-processing
Solution Approach 2:
The pre-bending process applies a preliminary anti-action by creating reverse curvature in the substrate that opposes the anticipated thermal expansion and distortion forces during DED. This counter-curvature acts as a pre-compensation mechanism that neutralizes the harmful thermal effects
2Reliability
If peening and rolling methods are used for stress relief, then residual stress is reduced, but cost and complexity increase
Solution Approach 1:
The invention extracts the stress relief function from separate post-processing operations (peening, rolling) and integrates it into the substrate preparation phase through pre-bending. This eliminates the need for complex additional equipment and processes while achieving the same stress management objective
3Ease of manufacture
If thermal energy is applied during DED, then material deposition and fusion are enabled, but thermal distortion and residual stress accumulate
Solution Approach 1:
The invention changes the initial geometric parameter of the substrate by pre-bending it to a specific reverse curvature. This parameter change in the substrate geometry compensates for the thermal parameters (expansion, contraction) that occur during DED, maintaining dimensional accuracy despite thermal cycling
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
Reduces residual stress and distortion in DED-manufactured components, improving material utilization efficiency, reducing waste, and enabling production of large-sized metal structures within specified tolerances, thus enhancing productivity and cost-effectiveness.
Implementation Method 1
directing a flow of gas with a velocity greater than a threshold velocity toward a substrate to be processed
Implementation Method 2
thermal source to melt a source of metal into metallic molten material that is deposited onto a surface of a base material
Data Source
AI summary
Provided are a mount system and systems and methods using the mount system for manufacturing objects, especially titanium and titanium alloy objects, by directed energy deposition. The methods include thermally pre-bending the substrate onto which the object is to be manufactured to form a pre-bent substrate, attaching the pre-bent substrate to a jig using the mount system as an underlying support, pre-heating the substrate, and forming the object on the pre-heated, pre-bent substrate using a directed energy deposition technique.