First EuroStir ® Workshop at TWI: 'Friction stir welding - making it work for you' (16 July 2002)
By: Stephan Kallee (TWI Ltd)
The first EuroStir ® Workshop, held at TWI on 16 July 2002, was well attended with nearly 100 attendees, mainly from the United Kingdom. The day started off with lectures on process fundamentals and industrial applications of friction stir welding. An introduction to the structure of the EuroStir ® project was given by Stephen Webster (Corus). An afternoon of 'show and tell' in TWI's laboratories included the first public demonstrations of straight butt welds in copper sheets and using a tool normal to the workpiece for non-linear butt welds ( Fig.1 and 2). Proceedings are available from TWI. [1]
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Fig.1. A welding speed of 0.5m/min was used for FSW of a 6mm thick 5083 aluminium alloy, using tools normal to the workpiece surface
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Fig.2. Demo of FSW of copper with on-line video surveillance using the high-force head of the ESAB SuperStir
TM machine at TWI under position control
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Role of DTI in the EuroStir ® Project
Phil Barham (DTI) gave an introduction to the activities of the UK's Department of Trade and Industry within the EUREKA scheme. The aim of EUREKA is to increase competitiveness and scientific excellence in order to generate higher levels of sustainable growth and productivity in a modern economy. It aims to create awareness; encourage implementation of generic new technologies & processes that lead to more productive processes and more competitive products.
Friction stir welding has the potential to improve process productivity as well as product performance and reliability in many engineering sectors. DTI wants to support awareness events such as the EuroStir ® workshops to help companies to weigh-up the relative technical and commercial benefits of the FSW process.
DTI supports collaborative projects, such as EuroStir ®, that will accelerate the implementation of the FSW process through:
- Optimisation of process parameters.
- Characterisation of weld performance.
- Economic assessment.
- Improved confidence in the process, particularly for safely critical applications.
Opportunities still exist for UK SMEs to participate in EuroStir ® via DTI subsidised demonstrations, which will give access to:
- TWI's facilities & FSW machines.
- TWI expertise.
FSW Process Fundamentals
Dave Nicholas (TWI) gave a presentation on FSW tools; equipment; workpiece materials; and benefits.
Equipment for Friction Stir Welding
Jonathan Martin (Smart Technology Group Ltd [2] - Crawford Swift) gave an overview on characteristics of FSW; effects of machine tool design ( Fig.3); and machine tool configurations ( Fig.4).
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Fig.3. Structural stiffness of FSW machines
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Fig.4. Multi Axes FSW Machine
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Current and Potential FSW Applications
Stephan Kallee (TWI) listed extensive applications in the following categories:
- Single skin panels.
- Hollow panels.
- Sandwich panels.
- Heat sinks.
- Tubes.
- Innovative concepts.
- 3D Joints.
- Fuel tanks.
- Castings.
- Housings.
- Replacement of rivets.
FSW Comparative Process Economics
Mike Turner listed and explained the cost categories relevant to FSW and concluded the following:
- Before even starting a detailed economic analysis, the major technical and commercial drivers need to be identified and roughly quantified.
- Travel speed alone is not even a coarse economic comparator where joining processes are radically different in principle.
- Attempts at a rigorous analysis frequently expose that the sources of, and actual costs of the current procedure are not fully known.
- It is not possible to produce a 'generalised' statement of comparative costs, e.g. because for 'consumables' discounts are available of up to 60% on list prices to some companies.
The following EuroStir ® Collaborators attended the first workshop:
- Angel Trains.
- Circle Technical Services.
- Corus.
- DTI.
- DLR - German Aerospace Center.
- HSBC Rail.
- Promweld.
- Smart Technology Group.
- Triton Tooling.
- TWI.
In the discussions after the workshop and on the quality assessment questionnaire the following feedback was given:
- 'I thought I knew already almost everything about FSW - but I realized that visits to TWI could be more frequent. I enjoyed the presentations on your Workshop and was able to take quite a lot back for my people home and our educational tasks ... Congratulations for the wonderful job ... and the very friendly atmosphere.'
- 'I was impressed with yesterday's seminar on FSW and the excellent attendance, which must have been very gratifying. I also found the technical content interesting - there is always something new to learn about the process.'
- 'I thoroughly enjoyed yesterday's meeting. FSW is indeed an impressive process.'
References
- Proceedings of the first EuroStir workshop cost £22.50 and are available from carol.fielding@twi.co.uk
- Company Profile: www.eurostir.co.uk/eurostir_smart.html