Bobbin Friction Stir Weld Hole Repair Using a Consumed Plug

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Solution Overview

Problem

Bobbin friction stir welding often creates holes when the pin breaks during the welding process, which are undesirable in certain locations and require repair.

Innovation Solution

A method involving inserting a plug into the hole, reshaping it to secure it in place, and creating a second weld seam that consumes the plug, using either the same or a different bobbin friction stir welding tool, to fill and repair the hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bobbin friction stir welding is used to create weld seams, then welding efficiency and structural reinforcement are improved, but holes are created in the component when the pin breaks or is removed

Engineering Contradiction:

Improvewelding efficiencyVSAvoidhole creation in weld seam

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The method performs preliminary actions by inserting a plug into the hole and reshaping it to secure the plug before creating the second weld seam. This preliminary plug insertion and reshaping prevents the harmful effect of holes in critical locations while maintaining the efficiency benefits of bobbin friction stir welding.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of hole creation into a beneficial repair process. The hole created by pin breakage or removal is transformed into an opportunity to insert a plug that will be consumed during a second weld pass, ultimately eliminating the hole and creating a reinforced weld seam with the plug material integrated into the final weld.

Inventive Principle:

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

2Reliability

If a plug is inserted into the hole and reshaped to secure it, then the hole is filled and structural integrity is improved, but additional processing steps are required

Engineering Contradiction:

Improvestructural integrityVSAvoidnumber of processing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the hole repair operation with the welding process itself. The plug insertion and reshaping steps are followed by creating a second weld seam that consumes the plug, combining the repair function with the joining function in a single integrated process rather than separate operations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The second weld seam performs a dual function: it joins the components together while simultaneously consuming the plug material to fill the hole. The welding process itself serves the purpose of eliminating the defect, rather than requiring a separate filling or sealing operation.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the same bobbin friction stir welding tool is used to create both the first and second weld seams, then tool consistency is maintained, but the tool must be repositioned and reconfigured

Engineering Contradiction:

Improvetool reusabilityVSAvoidtool repositioning time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The bobbin friction stir welding tool is designed to perform multiple functions: creating the first weld seam, allowing plug insertion and reshaping, and then creating the second weld seam that consumes the plug. The same tool is used for both welding operations, demonstrating multi-functionality and reducing the need for different specialized tools.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Effectively repairs holes by ensuring the plug is securely integrated and consumed within the weld seam, maintaining structural integrity and eliminating voids, suitable for various components including aircraft parts.

Implementation Method 1

The rotating pin experiences friction from the welded component causing localizing warming, softening, and intermixing of materials

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The step of reshaping the plug is performed while the plug is inserted into the hole. The step of reshaping the plug secures the plug inside the hole

Methodology Applied

Scientific EffectPlasticity: Plasticity

Implementation Method 3

The step of creating the second weld seam is performed using a second bobbin friction stir welding tool. The second weld seam passes through the plug secured in the hole, and the plug is consumed during the step of creating the second weld seam

Methodology Applied

Scientific EffectFriction welding: Friction Welding

Data Source

PatentUS11278986B2Repairing holes created in components during bobbin friction stir welding

Publication Date: 2022.03.22 THE BOEING CO

AI summary

Disclosed herein are systems, methods, and devices for repairing holes in weld seams created by bobbin friction stir welding tools. A hole may be created when a welding tool or, more specifically, a pin of the tool is removed or otherwise extracted from a weld seam created by the tool. The method may involve inserting a plug (e.g., a rivet) into the hole, reshaping the plug in the hole (e.g., riveting) thereby securing the plug in the component, and creating another weld seam through the plug thereby consuming the plug. In some embodiments, the hole may be reshaped prior to inserting the plug. For example, the hole may be drilled out and/or a countersink may be created on one or both ends of the hole. Furthermore, the plug may extend outside of the hole prior to its reshaping and, in some embodiments, even after reshaping.