Friction Stir Welding Pin Force Detection via Inductive Sensor

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for friction stir welding, particularly in 3D applications, face challenges in accurately measuring mechanical forces and process parameters like axial force and torque near the welding process due to the complexity of compensating for weight forces and the use of gravity sensors far from the point of action, leading to measurement errors.

Innovation Solution

A device and method that utilize a strain gauge sensor attached to the tool bell, amplified by an antenna, to directly measure forces acting on the welding pin tip, combined with a piezoelectric force-measuring sensor and inductive power supply, allowing precise recording of axial force, torque, and temperature at the welding pin tip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If gravity sensors are used to measure forces in 3D friction stir welding applications, then measurement coverage is achieved, but measurement precision deteriorates due to distance from point of action and complex weight force compensation

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidweight force compensation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a force measuring sensor as an intermediary device positioned between the welding tool and the workpiece. This sensor directly measures the axial force at the point of action without requiring distant gravity sensors or complex compensation calculations, thereby improving measurement precision while reducing device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the gravity-based measurement system with a direct mechanical force sensing system. Instead of using gravity sensors that require complex compensation for weight forces and distances, the invention uses a force measuring sensor that directly detects the mechanical forces at the welding interface, simplifying the measurement system and improving accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If force measuring sensors are positioned far from the welding pin tip, then device complexity is reduced, but measurement precision deteriorates due to lever arm errors and distance effects

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidsensor positioning simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent positions the force measuring sensor in a different spatial dimension - integrated within the tool structure at the point of action rather than positioned remotely. This dimensional repositioning allows direct measurement of forces at the welding interface, eliminating lever arm errors and distance effects while maintaining operational simplicity through integrated design

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

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

Enables accurate and precise control of axial contact pressure and torque during friction stir welding, reducing measurement errors and improving process control in complex 3D applications by providing real-time data close to the point of action.

Implementation Method 1

A device and method that utilize a strain gauge sensor attached to the tool bell, amplified by an antenna, to directly measure forces acting on the welding pin tip

Methodology Applied
Scientific EffectStrain gauge: Piezoresistive Effect

Implementation Method 2

combined with a piezoelectric force-measuring sensor and inductive power supply, allowing precise recording of axial force, torque, and temperature at the welding pin tip

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

combined with a piezoelectric force-measuring sensor and inductive power supply, allowing precise recording of axial force, torque, and temperature at the welding pin tip

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

frictional heat is generated in the joining area of the materials to be joined by means of the friction between a rotating tool that is simultaneously moved in translation and applied with pressure

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3129184B1Method and apparatus for detection of mechanical forces at the tip of the welding pin in the process of friction stir welding
Publication Date: 2019.08.21 GRENZEBACH MASCHINENBAU GMBH
  • EP3129184B1 patent drawingFigure 1
  • EP3129184B1 patent drawingFigure 2
  • EP3129184B1 patent drawingFigure 3

AI summary

The invention relates to a device and a method for detecting the mechanical forces at the welding pin tip during friction stir welding, having the following features: a) a strip-shaped sensor (3) at a long side of a tool cup (9) holding a welding pin pen (12) by way of a pin shaft (13) using a tool receiving cone (14), and also holding a welding shoe (11); b) a conical narrowed portion (20) in the further region of the tool-receiving cone (14), which serves to receive a sensor (18) for detecting the axial force, the torque and the bending moment at the welding pin pen (12); c) a further narrowed portion in the front region of the tool-receiving cone (14), having three sensors (24) distributed across the circumferences at a distance of 120 degrees; d) a sensor signal amplifier having a rotor antenna (19) for receiving, amplifying and forwarding all detected measurement values, said measurement values being forwarded by a static antenna (17) to a machine control; and e) an inductive power supply system.