Friction Stir Welding Tool Temperature Estimation via Backing Member

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Solution Overview

Problem

Friction stir welding tools experience premature wear and overheating due to excessive temperature, leading to reduced tool life and potential poor joint quality, as direct temperature monitoring is complex and costly, and existing methods may inadvertently shorten tool life by focusing on the workpiece temperature rather than the tool's temperature.

Innovation Solution

A friction stir welding apparatus with a temperature detector on the backing member to estimate the welding tool's temperature, allowing for monitoring and control of the tool's temperature status, including adjusting processing conditions or ending the welding process to prevent overheating, thereby extending tool life and ensuring joint quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a temperature detector is included in the welding tool to directly detect the temperature of the welding tool, then the temperature monitoring precision is improved, but the device complexity and cost increase due to requiring a remote-controlled measurement system

Engineering Contradiction:
Improvetemperature monitoring precisionVSAvoidapparatus configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the backing member as an intermediary to indirectly detect the welding tool's temperature. The temperature detector is mounted on the backing member to detect the temperature of the welding target portion, which serves as a mediator to infer the welding tool's temperature status without requiring direct measurement from the rotating tool itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a temperature correlation model between the welding target portion and the welding tool. By detecting the temperature of the welding target portion and using a predefined correlation, the system calculates an estimated temperature of the welding tool, effectively creating a indirect copy of the tool's temperature data.

Inventive Principle:
Principle #26Copying

2Productivity

If the welding tool temperature is allowed to increase during welding processing, then the welding efficiency is improved, but the welding tool life is reduced due to overheating

Engineering Contradiction:
Improvewelding efficiencyVSAvoidwelding tool life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent implements a feedback control system where the temperature detector continuously monitors the welding target portion temperature, the controller calculates the welding tool's estimated temperature using predefined correlation, and based on this feedback, the controller adjusts processing conditions or issues warnings to prevent excessive temperature increase that would reduce tool life.

Inventive Principle:
Principle #23Feedback

3Loss of time

If the welding tool is worn excessively, then the welding processing can continue, but the joining quality deteriorates and tool overheating occurs

Engineering Contradiction:
Improvewelding processing continuityVSAvoidjoining quality
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent performs preliminary detection of welding tool wear status by monitoring temperature trends before excessive wear occurs. The system detects abnormal temperature increases that indicate wear and takes preventive action (adjusting conditions or stopping processing) before the tool reaches a state that would compromise joining quality.

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 effectively monitors and manages the welding tool's temperature, preventing overheating and extending its life while ensuring the quality of joints by indirectly detecting the tool's temperature through the backing member, simplifying the apparatus configuration and reducing maintenance costs.

Implementation Method 1

a temperature detector configured to detect a temperature of a temperature measurement point provided in the backing member

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a protrusion provided at the tip of a welding tool is, while being rotated, pressed against a welding target portion of a plurality of steel members to be joined, so that the welding target portion and its surrounding portion are softened due to frictional heat

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2511038B1Friction stir welding apparatus and method
Publication Date: 2019.01.23 KAWASAKI JUKOGYO KK
  • EP2511038B1 patent drawingFigure 1
  • EP2511038B1 patent drawingFigure 2
  • EP2511038B1 patent drawingFigure 3

AI summary

In a friction stir welding apparatus (1), a temperature measurement point (T) is provided in a backing member (21). The backing member (21) supports workpieces (2) during welding by contacting a welding target portion (3) at an opposite side to a side at which the welding tool (4) contacts the welding target portion (3) during the welding in which the welding tool (4) moves and presses the welding target portion (3) of the workpieces (2) while rotating. Further, the friction stir welding apparatus (1) includes: a thermocouple (34) and a temperature measurement device (35) which are configured to detect a temperature of the temperature measurement point (T); a temperature monitor (53) configured to calculate an estimated temperature of the welding tool (4) from the detected temperature of the temperature measurement point (T), based on a predefined correlation between a temperature of the welding tool (4) and a temperature of the backing member (21); and a controller (S1) configured to perform a predetermined procedure based on the estimated temperature of the welding tool (4) so as to prevent overheating of the welding tool (4).