Barrier Tool Head Assembly for Flash-Controlled Friction Stir AM

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Solid state additive manufacturing processes like Additive Friction Stir (AFS) generate significant flash, requiring costly and time-consuming secondary machining processes to remove, which increases production time and cost, and reducing layer thickness only exacerbates the issue by increasing the number of layers needed.

Innovation Solution

A tool head assembly with barriers that extend along the side surfaces of the deposited layers to constrain the material from extruding past the edge of the shoulder, reducing flash generation and eliminating the need for secondary finishing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional AFS process is used without barriers, then material can be deposited efficiently, but significant flash is generated requiring secondary machining

Engineering Contradiction:
Improvelayer deposition efficiencyVSAvoidflash generation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

A barrier component is introduced as an intermediary element between the tool head and substrate. This barrier physically blocks the plasticized material from extruding past the shoulder edge, thereby preventing flash formation while allowing the AFS deposition process to continue efficiently. The barrier acts as a mediator that separates the material flow path from the unwanted flash generation zone.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tool head assembly is segmented into functional components including the barrier element that can be independently positioned and adjusted. This segmentation allows the barrier to be optimized specifically for flash control without affecting the overall deposition mechanism, enabling independent optimization of flash prevention while maintaining deposition efficiency.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If layer thickness is reduced to generate less flash, then flash amount decreases, but number of layers increases making the process more time-consuming

Engineering Contradiction:
Improveflash amountVSAvoidbuild time
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The invention converts the harmful flash generation mechanism into a beneficial controlled process. By introducing the barrier, the material that would otherwise form flash is redirected and contained, forming complete layers instead. This transforms the flash problem into an opportunity for improved layer formation without requiring reduced layer thickness, thereby maintaining build speed while eliminating flash.

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

3Manufacturing precision

If secondary machining processes are added to remove flash, then manufacturing precision is improved, but production time and cost increase

Engineering Contradiction:
Improvesurface finish qualityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The barrier is positioned to prevent flash formation during the deposition process itself, performing the flash control action preliminarily before any machining is needed. This preliminary prevention eliminates the need for subsequent corrective machining operations, thereby maintaining manufacturing precision while preserving production efficiency.

Inventive Principle:
Principle #10Preliminary action

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 solution significantly reduces flash generation by up to 90%, minimizing the duration and number of secondary finishing processes, thereby reducing production time and cost while maintaining efficient layer deposition.

Implementation Method 1

a rotating tool head is used to rotate and push the feed material (e.g., a rod, a powder, etc.) onto a substrate (or the most recently deposited layer). Under axial loading and rotation, the feed material is locally heated and plasticized

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a barrier configured to extend along a side surface of the at least one layer as the at least one layer is deposited onto the substrate such that the barrier is configured to constrain the material from extruding past an edge of the shoulder

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP3738706B1Tool head assembly for solid state additive manufacturing and corresponding method
Publication Date: 2022.02.09 THE BOEING CO
  • EP3738706B1 patent drawingFigure 1
  • EP3738706B1 patent drawingFigure 2
  • EP3738706B1 patent drawingFigure 3

AI summary

The present application relates to a tool head assembly (104) for a solid state additive manufacturing apparatus (100) which includes a tool head (110) having a material passage (120) configured to receive a material therein. The tool head (110) is configured to deposit the material from the material passage (120) onto a substrate (102) of the solid state additive manufacturing apparatus (100) to form at least one layer (142) of the material on the substrate (102). The tool head (110) includes a shoulder (130) configured to contact the material such that rotation of the tool head (110) frictionally stirs the material. The tool head assembly (110) includes a barrier (112) configured to extend along a side surface (154) of the at least one layer (142) as the at least one layer is deposited onto the substrate (102) such that the barrier is (112) configured to constrain the material from extruding past an edge (136) of the shoulder (130).