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FP7

FlexiFab Report Summary

Project ID: 606156
Funded under: FP7-SME
Country: Belgium

Final Report Summary - FLEXIFAB (Flexible fabrication of lightweight aluminium transport structures)

Executive Summary:
Breakthrough in friction stir welding through an automated robotic system will contribute to European industry competitiveness
FlexiFab project has achieved its stated goal, providing clear advantages for SMEs aiming to achieve accurate robotic friction stir welding (FSW)

The aim of the FlexiFab project was to develop a flexible Friction Stir Welding (FSW) system capable of automatically fabricating complex structures, in a variety of joint configurations, from a range of aluminium alloy grades and thicknesses used in the transport sector. Aluminium has several unique characteristics which need to be considered when fusion welding. Without care given its reactivity to air and high thermal conductivity/expansion, welds are prone to a wide variation of defects such as undercutting, excessive melt-through, incomplete fusion, incomplete joint penetration, porosity and cracking.
This was the issue addressed by the project FlexiFab - “Flexible fabrication of lightweight aluminium transport structures”, co-funded by the EU FP7 Research for the benefit of SME associations, which commenced on 1st November 2013. FlexiFab has a wide scope of application areas covering linear welds to more complex geometries. It will address the needs to improve labour productivity in the metal-working sector and alleviate the serious lack of skilled aluminium welding personnel in Europe.
After three years of research, the partners were able to develop an automated robotic system to enable welding of aluminium components and parts, which provides key competitive advantages to the (SME-dominated) European metal workers and fabricators, by providing a cost-effective method of fabricating aluminium structures that:
- Enables European fabricators, metal-workers and welding companies to effectively compete in the growing use of aluminium alloys for the light-weight transport sector;
- Capitalises on the increasing pressure to replace traditional iron and steel material with aluminium alloys to reduce weight and thus fuel consumption of vehicles, trains, ships/boats and aeroplanes;
- Reduces the costs associated with the fabrication of aluminium structures, especially focussed on components used within the transport sectors;
- Develops new and protectable IP in the area of automated aluminium welding systems, providing European manufacturing industries with added competitiveness and enhancing the move into the ‘knowledge-based’ manufacturing sector.
With this, the mainly SME-dominated European fabricators, metal workers and welding companies at large are poised to benefit from a significant reduction in the costs associated with the welding of aluminium components and structures (mainly due to the lack of scrappage and re-working required from an automated system) and are able to create better working conditions for their workforce, as expert welding knowledge will still be required, but physical demands will be greatly reduced.
The project was comprised of a transnational consortium, which includes ten partners:
- European Federation for Welding, Joining and Cutting (Belgium)
- Asociatia de Sudura din Romania (Romania)
- Meta Vision Systems Ltd. (UK)
- Innora SA (Greece)
- igm Robotersysteme AG (Austria)
- Boluda Division Industrial SL (Spain)
- RRS Schilling GmbH (Germany)
- TRA-C Industrie (France)
- TWI Ltd. (UK)
- Lund University (Sweden)

Friction stir welding and robots – how it as accomplished
Looking back at what was developed in the FlexiFab project and answering the initial question “Can a robot be used for 2D and 3D FSW”? With FlexiFab, it can.
The bold aim of FlexiFab project, to do FSW with a robot, led into the development and demonstration of the following:
• Integration of the robot software to seam tracking sensor so that the robot end effector can follow the joint between two curvilinear components;
• Integration of the robot software to the component sensor so that the robot end effector can follow the component surface geometry either side of the joint between two curvilinear components.
The architecture of the prototype system developed consists of several subsystems and software components to enable path adjustment and control algorithm modifications at the fast low-level controllers, which can be used in any commercial robot for a diversity of FSW techniques including floating-bobbin, corner, stationary shoulder and AdStir, along linear, circumferential and complex 3D weld paths.

The research leading to these results has received funding from the European Union's Seventh Framework Programme managed by REA-Research Executive Agency FP7/2007-2013 under grant agreement no FP7-SME-2013-2-606156.

Full version with images in Annex 1.

Project Context and Objectives:
The FlexiFab project developed a flexible manufacturing system capable of automatically fabricating complex structures, in a variety of joint configurations, from a range of aluminium alloy grades and thicknesses used in the transpost sector. The joining methods used are based on friction stir welding (FSW). This process uses a rotating tool that is plunged between two clamped plates and traversed along a joint line to form a solid-phase joint.

There are several benefits associated with FSW; it requires no shielding gas, no harmful welding fumes or hot metal spatter and no UV radiation hazards. Furthermore, due to slodi-state nature of the FSW process, it has low energy consumption, it produces welds with excellent mechanical properties and low distortion and it is able to join the "non-weldable" aluminium alloys such as the 2000 and 7000 series. Altough FSW does not suffer from the same quality issues as fusion welding, applying the technique on a robot is limited by the force that the robot can provide to successfully deploy the tools to make the weld. Within this project, new low force tools and techniques were developed to make FSW possible on a flexible platform.

The European Federation for Welding, Joining and Cutting (EWF), which represents the European SME metalworking community, has initiated this project to facilitate the adoption of automation within the aluminium joining industry. The successful implementation of the FlexiFab project will enable their members to optimise labour efficiency of highly skilled manual welders, safeguard theirs health (and working length of their careers), increase productivity of European companies and reduce costs so that they can, more effectively, compete with global players.

The main technical barriers which were solved within the FlexiFab project were:

- Absence of low force tooling suitable for robotic application

- Currently no industrial automated joint tracking and component sensing system exists which is suitable for path compensation in FSW

- No suitable welding head exists to accommodate and deploy the new FSW techniques

- Current systems are complex to operate and lack a bespoke user control interface system, to allow simple operation by welding engineers

FlexiFab developed a "Low-force" FSW tool suitable for a full range of joint configurations and operate at relatively low reactive force requirements, which then makes them compatible with low-cost robotic systems. These tools will be based on three new FSW tooling techniques; Fixed-Bobbin, Corner and AdStir. Process heads were developed for each technique with capabilities of carrying out FSW along multidimensional joint lines.

A sensor based closed-loop control system was developed to accurately position the FSW tool relative to the component surface and weld path. This will allow for automatic tracking of the joint line and real-time adjustment of tool trajectory to ensure joint quality.

To facilitate process monitoring and weld parameter development, a data logging system was developd to capture data from sensors and robot and process it to provide real time information on the weld status.

For batch and short production runs which can be large part of an SME's offering it is important to minimise fixturing costs and set up times. Novel commercially available flexible and reconfigurable work holding system were also assessed for welding suitability.

Project Results:
See attachment - Annex 2

Potential Impact:
Increased use of FSW will bring about significan economic advantages for its users but also major environmental and safety benefits. Use of Friction Stir Welding (FSW) instead of conventional fusion welding techniques will reduce power consumption, pollution (in terms of particulate fume, gases and noise) and improve safety for the operator who will no longer be exposed to dangerous UV radiation, extremely high temperatures and intense noise. Also, the FlexiFav system for FSW was developed as a turn key solution, meaning that the end-user just needs to buy a FlexiFab System and they will be able to do FSW.

The flexible, automated robotic FSW system developed in the FlexiFab will enable European SMEs in the metal working and fabrication industries to effectively take advantage of the accelerating trend towards light-weight structures for transport. FlexiFab will deliver significant benefits by providing a cost-effective method of fabricating aluminium structures that will:

- Enable European fabricators, metal-workers and welding companies to effectively compete in the growing use of aluminium alloys for use in the light-weight transport sector.
- Capitalising on the increasing pressure to replace traditional iron and steel material with aluminium alloys to reduce weight and thus fuel consumption of vehicles, trains, ships/boats and aeroplanes.
- Reduce the costs associated with the fabrication of aluminium structures, especially focused on components used within the transport sectors.
- The development of new and protectable IP in the area of automated aluminium welding systems
- To protect European manufacturing industries competitiveness and enhance the move into the "knowledge-based" manufacturing sector.

The idea behind having such a big variety of companies in the consortium, from the supplier to the end users, allowed the development of the FlexiFab system to be done having several potential customers in mind, but in a way that the existing suppliers would be interested in selling the FlexiFab System.

This means that the FlexiFab project targeted two different types of SME end-users:

- SMEs with no FSW capability
- SMEs with FSW capability but with the need to expand and/or become more flexible

The different categories provided different challenges and solutions:

SMES WITH NO FSW CAPABILITY

The FlexiFab system and all the know how (including the training) that foes with it will allow SMEs that have no FSW experience to gain it in a quick way. Also, the fact that the system is composed of several elements, both hardware and software, but all of them are connected allows a faster implementation of FSW in industry.

SMES WITH FSW CAPABILITY BUT WITH THE NEED TO EXPAND AND/OR BECOME MORE FLEXIBLE

One of the key barriers in the use of FSW is related to flexibility and the "extra-work" needed to change the configuration of the part that is going to be welded. The FlexiFab system, with all its hardware and software, will allow companies that already do FSW to be able to answer to the needs of their customers in a faster and more cost effective way, being it 2D or 3D welds, something that was extremely difficult to do before the FlexiFab system was developed.

DEMONSTRATION AND DISSEMINATION

The FlexiFab System was demonstrated to end-users but also to companies that seel of have interest in selling FSW systems. At the demonstration activity TWI presented the full FlexiFab system, its specifications and its capability. results from the industrial SME end-users cases in the project were also shown.

The results of the project were disseminated through several channels to raise awareness of the project and its results. The project partners jointly carried out some of the dissemination activities while some of the dissemination was also done independently by the partners. Typical technological dissemination of the project was made in trade fairs and similar events, while the scientific discoveries was disseminated at conferences and in journal publications.

The project partners together produced training/workshop material on the FlexiFab system including the tools, sensos and functionalities as well as covering the basices of FSW and the different variations. EWF and ASR also presented these materials in different industrial events.

EWF and ASR organised the partners to create several dissemination materials during the entire project duration, from flyers to posters.

DISSEMINATION OF SCIENTIFIC AND TECHNICAL RESULTS

The FlexiFab project produced scientific results of friction stir welding and on robotised friction stir welding. The main results were also presented at leading welding conferences and events. Some of the conferences/events are listed below:

- FABTECH 2014, FSW Technology for Marine Applications Session 17: Developments in Friction Stir Welding, November 2014, Atlanta USA, TWI and META. FABTECH is North America's Largest Metal Forming, Fabricating, Welding and Finishing Event and allowed a good dissemination of FlexiFab to both researchers and industrial users.
- EUROJOIN 9 conference, May 2015, Bergen, Norway, EWF. EUROJOIN is one fo the larger conference dedicated to Welding and Joining technologies in Europe.
- IIW Annual Assembly and Conference, June/July 2015, Helsinki, Finland, EWF. The IIW Annual Assembly and Conference in one of the biggest events dedicated to welding and joining in the world. This event/conference normally has over 500 participants.
- Booth at FABTECH Expo 2015, November 2015, META. North America's Largest Metal Forming, Fabricating, Welding and Finishing Event
- Presentation at the 11th International Symposium on Friction Stir Welding, May 2016, Cambridge, UK, RRS
- Presentation, flyers and marketing material distribution at the 69 IIW Annual Assembly and International Conference, July 2016, Melbournce, Australia.

The FlexiFab project was presented in other conferences and events in order to ensure engagement with academia and industry outside the consortium.

Besides the conferences, some results wre also presented in jounals. Below some examples of those publicantions:

- By Lu첡 Coutinho “Robotic Friction Stir Welding, Challenges and Solutions”, by M. Karlsson, F.B. Carlson, J. De Backer, M. Holmstrand, A.Robertsson, R. Johansson, L. Quintino, E. Assuncao (Portugal) at IIW 69 Annual Assembly and International Conference
- “Particle Filter Framework for 6D Seam Tracking Under Large External Forces Using 2D Laser Sensors” at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Fredrik Bagge Carlson, Martin Karlsson, Anders Robertsson, and Rolf Johansson
- Conference paper “Robotic Seam Tracking for Friction Stir Welding under Large Contact Forces” the Swedish Production Symposium 2016, Martin Karlsson, Fredrik Bagge Carlson, Jeroen De Backer, Rolf Johansson, Anders Robertsson
- Paper “Modelling and Identification of Position and Temperature Dependent Friction Phenomena without Temperature Sensing” at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2015) by Fredrik Bagge Carlson, Anders Robertsson and Rolf Johansson
Paper “Six DOF Eye to Hand Calibration from two DOF Measurements Using Planar Constraints” at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2015) by Fredrik Bagge Carlson, Anders Robertsson and Rolf Johansson

Some papers are also under development but are not yet published.

The full list of dissemination activities is reported below.

MULTIMEDIA DISSEMINATION

A website about the project was produced at the start of the project and has been running during the entire project duration. The website contains information on the project such as background on the project and the possible opportunities created in the project.

The website also contains News and Events, publications of the project and links to the project partners website.

Several videos were also prepared, some of them are currently present on YouTube:

Project introduction - https://www.youtube.com/watch?v=JLMDnOC5SFg
Demonstration 1 of the FlexiFab System - https://www.youtube.com/watch?v=q0oWjfeVXo8
Demonstration 2 of the FlexiFab System - https://www.youtube.com/watch?v=19OfWST0URs

TRAINING

The FlexiFab project also tackled training activities and needs. This was mainly related to the fact that the consortium agreed, from the beginning of the project, that in order to allow a proper and supported implementation of the FlexiFab results at an industrial level training was mandatory. This will also ensure an increase of employability in this technical area.

All of this combined will ensurre that the FlexiFab project will have an impact, not only at manufacturing level but also at a social level due to its potential in creating jobs.

POST-PROJECT EXPLOITATION

The project has produced a full robotized FSW system consisting of both hardware and software. The system was already tested based on real parts from some of the SMEs in the consortium. It was also assessed how easy would be to set up the system in order to ensure that the adoption of the FlexiFab system is less risky for SMEs, indendently of their experience with FSW.

Summarizing, the metal working industry represents the largest employer in EU manufacturing, accounting for 10% of value-added, 12.5% of employment and 20% of all manufacturing companies. Increased automation is needed, not only so that we fulfil our role in maintaining EU competitiveness, but also to project a positive, highly innovative image which is required to attract young people into the metal working industry.
Being FSW a clean technology with proven positive results for welding aluminium, and the FlexiFab system a Robotised cell to use it with increased flexibility, it will contribute to raise the Interest of younger people in the welding profession, a goal of high relevance for EWF and ASR.

List of Websites:
www.flexifab.info

Project Coordinator - Eurico Assunção - egassuncao@ewf.be

Related information

Documents and Publications

Contact

Luisa Coutinho, (Director)
Tel.: +351 214211351
E-mail
Record Number: 197912 / Last updated on: 2017-05-11
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