Pre-Bent DED Substrate Mounting for Distortion Mitigation
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Solution Overview
Problem
Directed Energy Deposition (DED) additive manufacturing processes, particularly for titanium and titanium alloys, face challenges with residual stress and distortion due to thermal expansion and contraction, leading to geometric inaccuracies and potential failure, with existing methods being costly and inefficient in reducing these issues.
Innovation Solution
A method and system that minimize residual stress and distortion by controlling heat transfer through a reduced substrate contact interface, using a pre-bent substrate with thermal insulation and a ceramic-free support system, and optimizing the manufacturing atmosphere to reduce oxidizing agents and pollutant particles, allowing for improved material utilization and reduced waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional DED manufacturing is used, then material waste is reduced compared to conventional methods, but residual stress and distortion increase leading to geometric inaccuracies
Solution Approach 1:
The substrate is pre-bent to a predetermined curvature before DED manufacturing begins. This preliminary action creates a counter-curvature that compensates for the thermal expansion and contraction that will occur during the additive manufacturing process, thereby reducing residual stress and distortion in the final product while maintaining geometric accuracy
Solution Approach 2:
The substrate curvature is changed from flat to pre-bent, modifying the initial geometric parameter of the substrate. This parameter change allows the substrate to accommodate thermal stresses during DED processing, reducing distortion and improving manufacturing precision without increasing material waste
2Stress or pressure
If thermal insulation is applied to reduce heat transfer, then residual stress is reduced, but device complexity increases
Solution Approach 1:
The patent removes ceramic insulation materials from the support system, extracting the harmful element that causes excessive heat transfer and residual stress. Instead, a simplified metallic support system with controlled contact interfaces is used, reducing device complexity while still managing thermal effects through the pre-bent substrate design
Solution Approach 2:
The pre-bent substrate acts as an intermediary between the DED process and the support system. It mediates thermal stress by absorbing and distributing heat through its curved geometry, reducing the need for complex insulation structures while maintaining stress control
3Shape
If substrate contact interface is reduced, then heat transfer is minimized reducing distortion, but manufacturing precision control becomes more difficult
Solution Approach 1:
The substrate contact interface is designed with local variations in contact area and pressure distribution. Specific regions of the substrate have optimized contact characteristics that control heat transfer locally, allowing distortion reduction while maintaining overall manufacturing precision through localized quality control
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 approach results in DED products with reduced residual stress and distortion, enhancing strength, fatigue resistance, and durability, while increasing throughput and yield within specified tolerances, and reducing manufacturing costs by minimizing material waste and rework.
Implementation Method 1
a thermal source to melt a metal material and deposit successive layers of molten metal onto a substrate to form a workpiece
Implementation Method 2
Thermal expansion and contraction can occur as a result of transient thermal excursions and steep thermal gradients that can be present during DED
Implementation Method 3
a gas jet device to direct a cooling gas to accelerate cooling of the as-solidified metal
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.