RF Device Interior Channel Surface Finish via Abrasive Flow Machining

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Solution Overview

Problem

Additive manufacturing techniques often result in passive radio frequency devices with undesirable surface roughness, which can lead to scattering loss and affect the functionality of these devices, and conventional methods like sanding or grinding are ineffective in achieving desired surface roughness, especially in complex internal channels.

Innovation Solution

Combining additive manufacturing with abrasive flow machining to form structures with desired surface roughness by using a viscous media containing abrasive particles to remove material from interior channels, allowing for precise control of surface roughness in complex geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If additive manufacturing is used to form passive radio frequency devices, then complex internal channels can be created, but surface roughness becomes undesirable and causes scattering loss

Engineering Contradiction:

Improveinternal channel geometryVSAvoidsurface roughness

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

A viscous media containing abrasive particles is introduced as an intermediary substance to achieve the desired surface finish. The media flows through the complex internal channels and deposits abrasive particles that mechanically remove material, thereby smoothing the surface while preserving the complex geometry that would be difficult to achieve with conventional machining methods

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Traditional mechanical finishing methods like sanding or grinding are replaced with abrasive flow machining. Instead of using rigid mechanical tools that cannot access complex internal geometries, the patent uses a flowing viscous media that can adapt to and finish any internal channel shape, substituting a flexible fluid-based system for a rigid mechanical one

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional methods like sanding or grinding are used to improve surface roughness, then surface finish may be improved, but they are ineffective in complex internal channels

Engineering Contradiction:

Improvesurface roughnessVSAvoidaccessibility to internal channels

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs hydraulic principles by using a viscous media that flows under pressure through the internal channels. This fluid-based approach allows the abrasive material to be delivered to and move through complex internal geometries that are inaccessible to conventional mechanical tools, enabling surface finishing in locations that would otherwise be impossible to reach

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 combination achieves passive radio frequency devices with desirable surface roughness, improving their functionality by reducing scattering loss and enabling the formation of complex internal channels with a maximum surface roughness of 63 microinches, which is not attainable through traditional methods.

Implementation Method 1

A viscous media containing abrasive particles is sent through the interior channel using abrasive flow machining equipment to form a desired surface roughness for the interior channel

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS10490899B2Additive manufacturing for radio frequency hardware

Publication Date: 2019.11.26 THE BOEING CO

AI summary

A method and apparatus is presented. A structure having an interior channel is formed using additive manufacturing equipment. A viscous media containing abrasive particles is sent through the interior channel using abrasive flow machining equipment to form a desired surface roughness for the interior channel.