Friction Stir Welding Tool Stepped Surface Blade Position

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Solution Overview

Problem

Existing friction stir welding tools generate large bead widths and thinning of materials due to increased biting of cutting blades, especially when tilted during welding.

Innovation Solution

A friction stir welding tool with a cutting blade positioned at the same height as the outer peripheral edge of a first surface, featuring a second surface with a lower protrusion height, and a main body with a thinned attachment surface to reduce blade biting and stabilize cutting depth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the cutting blade is attached to the outer periphery of the rotating member, then burrs can be removed during friction stir welding, but the bead width becomes large

Engineering Contradiction:
Improveburr removalVSAvoidbead width
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The cutting blade is positioned not only in the radial direction but also in the axial direction by utilizing the stepped structure (first surface and second surface). This multi-dimensional positioning allows the cutting edge to be precisely located at the peripheral edge of the first surface, enabling effective burr removal while controlling bead width.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cutting blade is positioned specifically at the peripheral edge of the first surface where burrs are generated, rather than attaching it to the entire outer periphery. This localized positioning ensures cutting action is applied only where needed, removing burrs while minimizing the width of the processed bead.

Inventive Principle:
Principle #3Local quality

2Reliability

If the tool is tilted to provide a push angle during welding, then welding performance is improved, but the cutting blade bites into the materials excessively causing thinning

Engineering Contradiction:
Improvewelding performanceVSAvoidmaterial thickness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The cutting blade's position is controlled in both radial and axial dimensions through the stepped structure. When the tool is tilted during welding, the axial positioning ensures the cutting edge maintains proper depth, preventing excessive biting into the material while still allowing the push angle to improve welding performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The stepped structure with different surface heights (first surface and second surface) creates a specific axial parameter for the cutting blade position. This parameter control ensures that even when the tool is tilted, the cutting depth remains consistent and appropriate, preventing material thinning while maintaining welding effectiveness.

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

Reduces bead width and minimizes material thinning while maintaining effective friction stirring and burr removal.

Implementation Method 1

generating frictional heat by pressing the probe against a butting portion between materials to be welded butted against each other while rotating the probe

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4659889A1Friction stir welding tool and friction stir welding method
Publication Date: 2025.12.10 KOBE STEEL LTD
  • EP4659889A1 patent drawingFigure 1
  • EP4659889A1 patent drawingFigure 2
  • EP4659889A1 patent drawingFigure 3

AI summary

The friction stir welding tool includes a main body and a probe that protrudes in an axial direction from a center of one tip surface of the main body, and frictional heat is generated by pressing the probe against materials to be welded while rotating the probe to perform friction stir welding of the materials to be welded. The tip surface of the main body has an annular first surface connected to a root portion of the probe and extending radially outward, and a second surface connected to an outer peripheral edge of the first surface via a step portion and having a protrusion height lower than that of the first surface. The main body is provided with a cutting blade for cutting surfaces of the materials to be welded. A cutting edge of the cutting blade is disposed at a radial position of the outer peripheral edge of the first surface, and a protrusion height of the cutting edge in the axial direction is equal to a protrusion height of the outer peripheral edge of the first surface.