Dual-Powder Additive Manufacturing for Smoother Finished Surfaces

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Solution Overview

Problem

Additive manufacturing processes often result in surface roughness and undesirable features like scanning lines or seams due to the melting and solidification of fusible materials, which can be aesthetically and functionally problematic.

Innovation Solution

A method involving the directional delivery and melting of two powder materials with an energy beam, followed by a finishing process such as chemical polishing, electropolishing, or mechanical polishing, where the second material is chosen for its targeted response to the finishing process to achieve lower surface roughness and improved aesthetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a scanning energy beam is used to fuse fusible material in additive manufacturing, then the material can be melted and solidified to form solid structures, but surface roughness is created which is aesthetically and functionally undesirable

Engineering Contradiction:

Improvesurface roughnessVSAvoidadditive manufacturing process

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

A finishing process is performed after the additive manufacturing process to remove surface roughness, scanning lines, and seams. This preliminary action on the surface (before final use) eliminates the harmful surface artifacts while preserving the bulk structure created by additive manufacturing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The surface roughness and scanning lines created by the additive manufacturing process are converted into removable material that can be selectively eliminated through finishing processes such as chemical polishing, electropolishing, or mechanical polishing, transforming the harmful surface artifacts into a benefit of enhanced surface quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If chemical polishing is applied to remove surface roughness, then surface smoothness is improved, but material is removed from the component

Engineering Contradiction:

Improvesurface smoothnessVSAvoidmaterial removal

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

Chemical polishing utilizes chemical reactions to selectively remove material from the surface. By controlling the chemical parameters (etchant composition, temperature, time), material is removed in a controlled manner to smooth the surface while minimizing excessive material loss.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Chemical polishing employs strong oxidizing agents that accelerate the removal of surface material through oxidative reactions. These strong oxidants enable rapid and uniform material removal to achieve smooth surfaces while controlling the depth of material loss.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

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 reduces surface roughness and enhances the appearance and functionality of additive manufactured articles by utilizing a second material that responds well to the finishing process, providing smoother and more refined surfaces compared to the initial material.

Implementation Method 1

delivering a first powder material to the build location on the substrate and melting it with the energy beam. A second powder material is delivered to the build location on the substrate over the first material and melted with the energy beam

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

the finishing process can comprise chemical polishing of the solid surface comprising the second material

Methodology Applied

Scientific EffectChemical polishing:

Implementation Method 3

the finishing process can comprise electropolishing of the solid surface comprising the second material

Methodology Applied

Scientific EffectElectropolishing:

Implementation Method 4

the finishing process can comprise mechanically polishing the solid surface comprising the second material

Methodology Applied

Scientific EffectMechanical polishing:

Data Source

PatentUS11123819B2Additive manufacturing method

Publication Date: 2021.09.21 HAMILTON SUNDSTRAND CORP

AI summary

A method of making an article is disclosed. According to the method, an energy beam is directed to a build location on a substrate, and a first powder material is delivered to the build location on the substrate and melted with the energy beam. A second powder material is delivered to the build location on the substrate over the first material and melted with the energy beam. The direction of the energy beam and delivery and melting of the first and second powders is repeated at multiple build locations on the substrate to form a solid surface of the article of the second material. The solid surface comprising the second material is subjected to a finishing process.