DED Base Preheating for Low-Stress Additive Deposition

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Solution Overview

Problem

Direct energy deposition (DED) processes face issues with rapid heating and cooling leading to material stresses, distortion, and defects due to rapid expansion and contraction, which affect the weldability and geometry of the final product.

Innovation Solution

Conductive heating of the base during the DED process, where the base is heated to a temperature 100 to 200 degrees Celsius above ambient temperature, or the temperature difference between the base and the melting material is reduced to 100 to 200 degrees Celsius, to control the additive manufacturing process and improve weldability and reduce stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rapid heating and cooling is used in DED process, then deposition speed is improved, but material stresses and distortion increase

Engineering Contradiction:

Improvedeposition speedVSAvoidmaterial stresses

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The base is preheated to a temperature 100-200°C above ambient temperature before material deposition begins. This preliminary heating action reduces the thermal shock when hot material contacts the base, thereby reducing material stresses and distortion while maintaining rapid deposition speeds

Inventive Principle:

Principle #10Preliminary action

2Productivity

If rapid heating and cooling is used in DED process, then deposition speed is improved, but geometry accuracy deteriorates

Engineering Contradiction:

Improvedeposition speedVSAvoidgeometry accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The base is preheated to a temperature 100-200°C above ambient temperature before material deposition begins. This preliminary heating action reduces thermal shock and minimizes distortion during rapid deposition, thereby maintaining geometry accuracy while achieving high deposition speeds

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If base temperature is increased, then weldability is improved, but thermal expansion increases

Engineering Contradiction:

ImproveweldabilityVSAvoidthermal expansion

Core Design Contradiction:

Ease of manufactureVSShape

Solution Approach 1:

The base temperature is optimized to a specific range (100-200°C above ambient) that improves weldability by reducing thermal shock and promoting better material fusion, while avoiding excessive temperatures that would cause significant thermal expansion and geometry distortion

Inventive Principle:

Principle #35Parameter changes

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 properties of the final product by reducing stresses and distortion, improving weldability, and minimizing deposition defects, resulting in a stronger and more accurately formed object with desirable geometry.

Implementation Method 1

Conductive heating of the base during the DED process, where the base is heated to a temperature 100 to 200 degrees Celsius above ambient temperature

Methodology Applied

Scientific EffectConductive heating: Conduction (thermal)

Implementation Method 2

an energy source configured to selectively direct an energized beam at the material to fuse a new layer of the material to a previously formed layer

Methodology Applied

Scientific EffectLaser heating: Laser

Data Source

PatentUS11396063B2Systems and methods for in process heating for direct energy deposition applications

Publication Date: 2022.07.26 ROSEMOUNT AEROSPACE INC

AI summary

A system used to additively manufacture an object layer-by-layer using direct energy deposition (DED) includes a base where the object is formed, a depositor configured to deposit material layer-by-layer on the base or a previously deposited layer of the object, an energy source configured to selectively direct an energized beam at the material to fuse a new layer of the material to a previously formed layer, and a heating element in contact with at least a portion of the base and configured to supply heat to the base.