Angle-Head Friction Stir Welding with Spindle Force Feedback

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Solution Overview

Problem

Existing friction stir welding methods and devices face challenges in achieving high efficiency and reliability, particularly in difficult-to-access locations due to high forces that can cause damage to the tool and spindle.

Innovation Solution

The use of an angled adapter head allows for friction stir welding in hard-to-reach areas by measuring forces on the spindle and controlling the process based on these measurements, adjusting parameters to prevent exceeding permissible loads, and incorporating a machine constant to convert spindle forces into tool forces, thereby preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If friction stir welding is performed in difficult-to-access locations, then accessibility is improved, but the risk of tool and spindle damage increases due to high forces

Engineering Contradiction:
Improveaccessibility to difficult-to-reach positionsVSAvoidrisk of tool and spindle damage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback control system that continuously monitors forces acting on the spindle during friction stir welding and compares them against predefined maximum values. When force limits are approached, the system automatically adjusts process parameters (feed rate, normal force, rotational speed) to prevent damage to the tool and spindle, enabling reliable operation in difficult-to-access positions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic adjustment of process parameters based on real-time force measurements. The feed rate, normal force, and rotational speed are not fixed but are continuously adapted during welding to maintain forces within safe limits, allowing the system to operate reliably in challenging positions where static parameter control would be insufficient

Inventive Principle:
Principle #15Dynamics

2Productivity

If high forces are applied during friction stir welding, then welding efficiency is improved, but the risk of exceeding permissible loads increases

Engineering Contradiction:
Improvewelding efficiencyVSAvoidpermissible load capacity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent dynamically changes process parameters (feed rate, normal force, rotational speed) based on measured spindle forces to maintain optimal welding efficiency while staying within permissible load limits. The system adjusts these parameters in real-time to balance productivity with mechanical constraints

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A feedback control mechanism continuously monitors forces on the spindle and automatically adjusts welding parameters to prevent exceeding permissible loads. This ensures that high forces necessary for efficient welding are applied only when within safe operational limits, preventing damage while maintaining productivity

Inventive Principle:
Principle #23Feedback

3Ease of operation

If an angled adapter head is used to reach inaccessible positions, then accessibility is improved, but the complexity of the device increases

Engineering Contradiction:
Improveaccessibility to hard-to-reach areasVSAvoiddevice structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces an angled adapter head as an intermediary component between the spindle and the friction stir welding tool. This adapter enables the tool to reach difficult-to-access positions while the force measurement and control system manages the additional complexity by monitoring and controlling forces transmitted through the adapter

Inventive Principle:
Principle #24Intermediary (Mediator)

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 efficient and reliable friction stir welding in inaccessible positions by preventing tool and spindle damage through force-based process control, allowing for precise control of forces and moments acting on the tool.

Implementation Method 1

friction stir welding

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

friction stir welding

Methodology Applied
Scientific EffectFriction heating: Viscous Heating

Data Source

PatentEP3930952B1Method of friction stir welding and device therefor
Publication Date: 2023.06.14 STIRTEC GMBH
  • EP3930952B1 patent drawingFigure 1

AI summary

The invention relates to a method for joining or machining, in particular a friction stir welding method, using an apparatus (1), wherein a tool (6), in particular a friction stir welding tool, is driven via a spindle (2) with a spindle axis (4). In order to achieve a high level of reliability even when the method is applied at positions with poor accessibility, the invention provides that an adapter, in particular an angle head (3), is arranged between the spindle (2) and the tool (6), such that the tool axis (5) about which the tool (6) rotates does not coincide with the spindle axis (4), wherein a force acting on the spindle (2) is measured and the method is regulated depending on the force measured at the spindle (2). The invention also relates to an apparatus (1) for joining or machining, in particular for friction stir welding, having a headstock with a spindle (2) that is rotatable about a spindle axis (4) and a tool (6), in particular a friction stir welding tool, that is able to be driven about a tool axis (5) by the spindle (2).