Friction Welding Flash Removal Channels

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Solution Overview

Problem

In rotary friction welding, inefficient expulsion of plasticized material as flash can retain contaminants at the weld interface, and energy distribution is often asymmetric, leading to suboptimal welding results.

Innovation Solution

The implementation of flash removal channels in the weld surfaces, which can be circumferentially distributed and radially extending, shaped as chevrons, and optionally buried, to enhance flash removal and energy distribution, thereby improving the efficiency of the welding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional friction welding is used without flash removal channels, then the welding process is simpler, but flash (excess material) cannot be removed efficiently and contaminants remain at the weld interface

Engineering Contradiction:
Improvewelding process simplicityVSAvoidflash removal efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The flash removal system is segmented into multiple radially-oriented channels distributed around the weld interface. Each channel acts as an independent pathway for flash expulsion, collectively providing comprehensive flash removal coverage throughout the welding zone while maintaining a relatively simple overall process design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flash removal channels serve as intermediary structures that facilitate the expulsion of flash and contaminants from the weld interface. These channels mediate between the plasticized material at the interface and the external environment, enabling efficient flash removal without complicating the fundamental friction welding process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If flash removal channels are added to the weld surface, then flash removal efficiency improves, but the device complexity increases

Engineering Contradiction:
Improveflash removal efficiencyVSAvoidweld surface structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The flash removal channels are localized to specific regions of the weld surface where flash generation and accumulation occur. By concentrating the flash removal functionality at the interface zone rather than throughout the entire workpiece, the structural complexity is minimized while maintaining effective flash removal where it is most needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of trying to prevent flash formation through complex control mechanisms, the invention inverts the approach by providing dedicated pathways for flash expulsion. Rather than controlling the flash generation process, the system allows flash to form naturally and then efficiently removes it through the radially-oriented channels.

Inventive Principle:
Principle #13The other way round (Inversion)

3Device complexity

If conventional rotary friction welding is used without flash removal channels, then the equipment is simpler, but contaminants are retained at the weld interface reducing weld quality

Engineering Contradiction:
Improveequipment structureVSAvoidweld quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention converts the potentially harmful accumulation of flash and contaminants at the weld interface into a beneficial expulsion process. By providing radially-oriented channels, the system transforms the harmful buildup of material into a controlled flash removal mechanism that actively cleanses the weld interface of contaminants, thereby improving weld quality without requiring complex additional equipment.

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

4Device complexity

If no flash removal channels are provided, then the welding setup is simpler, but energy distribution in rotary friction welds remains asymmetric with inside diameters receiving less energy

Engineering Contradiction:
Improveweld surface modificationVSAvoidenergy distribution uniformity
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The flash removal channels are strategically positioned and oriented to address local energy distribution deficiencies in rotary friction welding. By placing channels at specific angular positions and orientations around the weld interface, the system creates localized variations in friction and heat generation that compensate for the inherent asymmetric energy distribution, particularly enhancing energy input at the inside diameter regions that normally receive less energy.

Inventive Principle:
Principle #3Local quality

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 channels facilitate efficient removal of flash, reduce the energy needed for interface conditioning, and allow for more uniform energy input, enhancing the quality and consistency of the weld by expelling contaminants and adjusting energy distribution based on workpiece geometry.

Implementation Method 1

Friction welding is the process for welding together two bodies or workpieces by converting mechanical energy to heat energy by the friction between the engaging weld surfaces of the two workpieces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

This is followed by upsetting when the temperature reaches a high enough level such that softening/melting of the workpiece material allows the workpieces to be pushed together, with liquid or quasi-liquid material being expelled as flash sideways from a plasticised zone at the interface

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3053698B1Friction welding
Publication Date: 2020.03.18 ROLLS ROYCE PLC
  • EP3053698B1 patent drawingFigure 1(a)~1(c)
  • EP3053698B1 patent drawingFigure 2
  • EP3053698B1 patent drawingFigure 3

AI summary

A friction welding process includes: providing a first workpiece having a first weld surface, and a second workpiece having a second weld surface; aligning the workpieces with the weld surfaces facing each other, moving one workpiece relative to the other workpiece, and engaging the first and second weld surfaces such that the movement raises the temperature at the weld surfaces to create a weld interface; and ceasing the movement and allowing the weld interface to cool to weld the workpieces together at the interface. The first workpiece has a plurality of flash removal channels formed in and/or adjacent to the first weld surface. The channels provide pathways for ejection of material from the weld interface during welding.