Final Report Summary - TAILORWELD (TAILORed Energy Distributions for Laser WELDing)
Executive Summary:
Laser beam welding is a high-performance joining process that is rapidly growing. The process offers a low distortion and high performance joining solution, achieving high productivity and consistent welds. The global market for laser systems for materials processing exceeds $10 billion per annum. The laser welding segment accounted for approx. $350 million in 2014 with an annual growth rate of 5%.
Despite these benefits and healthy growth, the uptake of laser welding technology is still limited amongst SMEs, for three related reasons: complexity, lack of flexibility, and difficulties in using lasers for ‘non-standard’ welds. Most existing laser systems are fitted with either a standard process head or a 2D galvanometer scanner. This relatively simplistic energy distribution is not directly suitable for many applications and significant laser welding expertise is often required to develop acceptable processing parameters.
The aim of the TailorWeld project was to develop and demonstrate an innovative laser welding system, which uses simple and robust diffractive optical elements that will increase the flexibility and simplify the application of laser welding. Diffractive optical element (DOE) is widely used in low power applications, generally in the visible wavelength, for applications such as optical interconnections and image processing. Their use in high power laser applications has been mainly limited to beam splitting, beam sampling and Gaussian-to-top hat beam shape conversion.
In order that the SMEs in the TailorWeld project manage the RTDs’ worked to deliver these benefits, the TailorWeld project had a series of Scientific, Technical, and Validation objectives.
Scientific objectives:
1. Generate detailed data on laser welding with tailored energy distributions for the three most industrially relevant materials and three typical joint combinations in the target markets.
Consequently, it was able to develop WPS (to ISO 15614) for three end-user applications, by end of month 15 of the project.
2. Produce validated thermo-physical semi-analytical models for conduction limited and keyhole laser welding by month 18 of the project, which is capable of modelling the resulting weld shape for end-user specified joints; applicable for the range of materials and joints specified in Objective 1.
Technical objectives:
3. Using the results of Objective 1, produce, test and validate a series of DOEs, which enabled the three end-user applications specified by ICP, HAL and GRA, by month 20 of the project.
4. By month 27 of the project, design and prototype a DOE laser welding head module which: allows the easy interchanging of DOEs, can integrate with commercially available laser welding process heads, and incorporates co-axial process monitoring for Quality Assurance purposes.
5. Using the result of Objective 2, by month 27 of the project, develop a DOE design tool which uses the semi-analytical models, is able to access look-up tables and numerical model data, and has a bespoke GUI to enable specification of energy distributions from the model for end-user specified joints in less than thirty minutes.
Validation objectives:
6. Integrate the DOE laser welding head module into a laser welding head(s) and laser source, and perform demonstrations of laser welding using the TailorWeld system at at-least one end-user SME site. Demonstrating the same productivity improvements as Objective 3 by month 31 of the project.
7. Perform a detailed techno-economic analysis of the results, in terms of weld quality and properties, for at least 3 different end-user requirements, were presented as case-studies to compare tailored energy distributions to existing methods, including full operating cost analysis, by end of the project.
At the end of the TailorWeld Project all of these objectives were achieved, demonstrating the success of the project.
Project Context and Objectives:
Laser beam welding is a high-performance joining process that is rapidly growing. High power lasers to a value of ~$440M were sold in 2015 meaning a growth by 17% from 2014. The reason for the sales growth of high power lasers can be attributed to developments in laser welding technologies providing a higher availability of fibre delivered Yb:YAG fibre lasers, Yb:YAG disc lasers and direct diode lasers. These new type of lasers have several benefits in comparison with CO2-lasers:
• Up to five times higher lifetime
• Beam switching making it easier to use one laser source for several work stations
• Fibre-guided beams which provides more stable beam delivery than mirror systems
• 3-4 times higher wall-plug efficiency
• Less service required
• No gas needed to create the laser beam
Despite this, mostly large enterprises have adopted laser welding. Among SMEs laser welding is still limited due to the following reasons:
• High initial investment cost (albeit the cost is decreasing)
• Complexity of setting up a laser welding system
• Complexity in finding good welding parameters and maintaining the system, very few laser welding engineers available
• Difficult to use for non-standard welds
At the start of the project EWF estimated that ~8000 of their members could significantly boost their competitiveness if they had access to a flexible laser welding process; either by retrofitting existing laser cutting equipment or by acquiring a new laser welding system.
Traditionally, rotationally symmetric laser beams with Gaussian-like or top hat-like profiles are used for welding since these are the beam-intensity profiles often generated by high power laser sources, particularly when the beam is guided by an optical fibre to the work-piece. The beam is then delivered onto the workpiece with a standard process head or a 2D galvanometric scanner. The Gaussian-like or top-hat like distributions are simplistic and not directly suitable for all applications which make finding the right parameters cumbersome and complex.
The TailorWeld concept aim is stated as:
“To develop and demonstrate an innovative laser welding system, that uses simple and robust diffractive optical elements (DOEs), which will increase the flexibility and simplify the application of laser welding; removing the key barrier to entry for SME fabricators”
To achieve this aim, a welding head incorporating a DOE must be designed so that SMEs easily can use DOEs and change between them for different manufacturing operations making their laser welding process flexible. The laser welding head should be easy to use to avoid having operators go through advanced training.
The companies that uses DOEs today usually decide on their DOEs through a trial-and-error approach, i.e they order an optic which they think will be suitable and if it does not work they order a new one. This quickly becomes expensive and time-consuming. TailorWeld will alleviate this problem with the development of a fast thermo-physical model that will be accessible through a Garphical User Interface. The model allows the SME end-users to quickly investigate the resulting joints from different beam profiles. These types of simulations can also be performed by commercial numerical software codes but they require expertise and the licensing costs are often high. The TailorWeld project instead aims at a fast license-free software that is easy to use. The modelling codes are simpler than the numerical codes but will be compared to numerical modelling during the project to assure that no key effects are missed.
DIFFRACTIVE OPTICAL ELEMENTS AND POTENTIAL BENEFITS
DOEs is a new method for controlling a laser beam in laser materials processing. The first one was made by the project partner HOLO/OR in 1991. DOEs have several beneficial properties:
• Can produce almost any energy distribution
• Robust, no moving parts
• Low cost
• Reduces the requirement for specialist laser welding operators
However DOEs are seldom used in industry because of the earlier mentioned complexities regarding beam design.
SMEs benefits from the TailorWeld system through:
• Replacement of expensive galvanometer systems with low-cost DOEs
• A low cost system for producing tailored energy distributions together with a tool to predict a suitable energy distribution
• A DOE laser welding head module which can be used on a new system or retro-fitted onto an existing system
• Built in process monitoring
• A processing head that allows for fast change of DOEs to allow for flexible production.
The TailorWeld system also enhances the performance of:
• Joining of dissimilar materials by compensating for different thermal properties
• Welding of crack-sensitive and phase sensitive materials through better thermal management by including several beams
• Multi-spot welding. Instead of doing multiple single-spot welds, the TailorWeld system allows for making one multi-spot weld.
POSSIBLE TECHNICAL BARRIERS
At the start of the project several technical barriers were identified and subsequently solved during the project:
1. Tailored energy distributions for envisaged new laser welding applications are not optimised:
This was overcome by studying welding with non-standard beam shapes through laser welding experiments with different materials and joint setups. The experiments were complemented with High-Speed Imaging to capture fluid flow effects and with thermal camera to study the temperature profile and cooling rates. The experiments are concentrated on the three applications chosen by the end-user SMEs in the project.
2. Current approach for producing tailored energy distributions is through trial-and-error which is not cost effective for end-users
Experimental results from 1 were used to validate the numerical models and in turn the fast semi-analytical models which are the base for the DOE design tool.
3. DOE laser welding head module with in-built process monitoring does not exist
A laser welding head that allows for fast interchange between DOEs was designed and a prototype manufactured.
4. Limited data on laser welding with DOEs for envisaged new welding applications
Welding experiments were conducted systematically and compared to competing processes
OBJECTIVES
The TailorWeld consortium established a number of objectives that needed to be fulfilled in order to deliver the TailorWeld system to the market. These objectives were divided into three phases. “Research phase”, “Technology Development Phase” and “Validation and Demonstration phase”
Research: The state-of-the-art on welding with non-standard beam shapes contained little information so the project had to generate data from experiments by monitoring the experiments and analysing cross-sections. Modelling and simulation was used to produce complimentary data.
Research: Very few mathematical models concerning welding with non-standard beam shapes existed before the project, particularly fast semi-analytical models. Thus the TailorWeld had to produce these models and validate them with experiments.
Technology: DOEs for the three end-user applications had to be produced and validated. The DOEs should decrease the weld time with at least 50 %.
Technology: Design and develop the earlier mentioned laser welding head with interchangeable DOEs and built-in process monitoring
Technology: Build a GUI that can access the semi-analytical models and use look-up tables to account for other effects. The calculation time should be shorter than 30 minutes.
Dissemination: Integrate the TailorWeld head in an existing laser system at one of the SME end-users and do a demonstration event.
Dissemination: Perform a techno-economic analysis of the results with regards to weld quality, weld properties and cost with existing technologies.
The main objectives of the TailorWeld project, can be divided into scientific and technological as well into dissemination and exploitation activities, which were held to spread the findings of the project and to ensure the uptake by industry. Despite the steady increase in sales of laser welding equipment, the uptake of laser welding in European SMEs is small due to complexity and the costs associated with it. By not adopting laser welding, there is a risk that the European SMEs may lose competitiveness. Laser weld systems typically deliver a Gaussian beam or a top-hat beam which sometimes is too simplistic. Diffractive Optical Elements (DOE) can be used to shape the beam to almost any profile making it possible to weld products where the standard beam shapes are not directly suitable. The aim of the TailorWeld project was to develop a complete laser welding system with a laser welding head incorporating a DOE and complementing easy-to-use software to calculate suitable energy distributions. The TailorWeld system targets SMEs and the goal is to remove the complexity barrier to allow for more SMEs to adopt laser welding.
The project had to make scientific and technological progress in order to fulfil these goals. Welding with non-standard beam shapes had been scarcely studied before the project particularly for DOEs. The project started out with categorising welding with tailored beams on three SME end-user applications defined in the project.
Concurrently two fast semi-analytical models for different welding modes (keyhole mode and conduction mode) were developed based on experiments and numerical modelling (published in scientific journals). Look-up tables that describe effects based on temperature were also developed to supplement the semi-analytical models.
The experiments on the end-user applications showed that DOEs could produce beneficial results in all three cases mainly by shortening weld cycle time. A laser welding head with a cartridge system for fast interchange between DOEs was developed. The welding head can be used on new laser systems or retro-fitted onto existing laser systems.
A DOE design tool with a GUI was developed to enable easy access to the semi-analytical models. The design tool also provides access to the look-up tables to study special welding effects. One of the applications considers welding with Duplex stainless steel, thus the design tool can predict the resulting ferrite/austenite ratio. The tool was designed with the three end-user cases in focus but additional materials were included in the software. The material data and look-up tables were stored in a text-file allowing users to add/modify materials and look-up criteria.
The TailorWeld head was installed at one of the end-user SMEs. Their galvanometric scanner was replaced with the TailorWeld head. The resulting weld was successful and reduced the weld cycle time. Installation and validation time was swift and successfully accomplished in just a few hours.
The TailorWeld consortium suggested several modifications to the EN ISO 15609 Standard regarding the Welding Procedure Specification (WPS) based on findings in the project to allow for tailored energy distributions.
The consortium also targeted training, through several routes, in order to ensure that companies interested in using the TailorWeld system will have access to trained staff.
Scientific results from the project have been presented in scientific journals and international conferences. In addition material has also been prepared for post-project dissemination in both scientific journals and at international conferences. Technological achievements have been presented at seminars, trade fairs, partner websites and a YouTube video was made explaining the project and its potential benefits.
Project Results:
See attachment - Appendix 1
See attachment for some of the dissemination materials
Additional information regarding WP 4:
Reparding the report on DOE design tool and GUI the consortium ended up extending the work carried out in WP 4 (responsible for the DOE design tool and GUI) for some more months, not because of delays, but to ensure that the results and tests from WP 5 could be fed into WP 4 to improve the results based on feedback from the end users. We discussed this with the PO and she approved our requests (please have a look at the emails in attachment). Based on this exchange and considering that D4.1 D4.2 and D4.3 were submitted correctly we believed that this would suffice and our email exhange with the PO made us believe that no report was needed since we did report, by email, the progress of WP4. Mainly, because, what was a risk identified by the reviewer and PO, due to the short time, ended up not causing any delay in the project and the consortium was able to deliver all the results identified at the beginning of the project. Adding to this, the requested report, at this time would pretty much be the same as what was reported in D4.1 D4.2 and D4.3 and the extra time was mainly used to improve the software and not to develop it.
However, in order to provide a clearer idea of the status of WP4 at M22, some more information is given bellow:
In M22 the GUI was practically finished and working but it had not been bug tested or tested for stability meaning that it still was in an early state, work on D4.2 and D4.3 was more harmonised and worked on together instead of worked on sequentially. An extension of the delivery date was asked for because of the following reasons:
• To be able to bug test the software more, which was mostly done in-house at LTU by other laser welding experts who had not been part in development of the software.
• To receive input from the end-users and be able to change the software accordingly. Training for the design tool was performed at the M24 meeting in Tel Aviv to identify possible flaws in the software regarding user-friendliness and to give end-users time to evaluate the software. The M24 was also used to get more feedback from the end-users, for example different choices of visualisations (2D or 3D) were presented to the project partners to see which detail of visualisation was desired. On this meeting it was also decided that LTU develop a user guideline to make sure that new users can use the software without expert support after the project ends.
• Use results from WP5 to further improve the software. The software was used on the WP5 experiments to test the software for real application cases. Also experimental results were used to further validate the software with the keyhole-mode model together with the look-up table for the GRA case.
Potential Impact:
The TailorWeld system has large potential as more and more European companies replaces their conventional welding equipment with laser welding equipment as the price of laser power sources decreases. A switch from arc welding to laser welding gives higher productivity, higher controllability and a smaller heat affected zone. Less heat input and smaller heat affected zones results in faster cooling which can be a drawback in crack-susceptible materials. Here the TailorWeld system could be used to incorporate pre- or post-heating in the process instead of having to do it in another process. LTU recently presented that laser remelting of welds created by laser-arc welding can create smoother weld geometry which can enhance fatigue life since surface geometry usually have a detrimental effect on it. The remelting was achieved by defocusing the beam and doing one more run over the weld. With the the Tailorweld system this could be done in only one run and the process would use less energy since the weld would not cool before the remelting beam. These two examples are just some of many potential applications where the TailorWeld system could provide benefits in comparison to traditional welding processes and existing laser welding solutions.
The TailorWeld project demonstrated the use of similar multi-beam optics in a case where the target was to achieve a 50/50 ferrite/austenite balance after welding by applying a post-processing beam. The balance between ferrite/austenite is mainly governed by the cooling cycle but can also be altered by shielding gas or added material. Achieving the desired balance is probably impossible by only using a standard laser beam but the TailorWeld head gives opportunity to tailor the cooling cycle in many ways. However the head is not enough since it is complex to correctly predict the desired beam shape. Here the DOE design tool is useful to avoid doing costly experiments. The complete TailorWeld system thereby creates new opportunities for laser welding.
Many SMEs, especially sub-contract firms, demands flexible machines and equipment to be able to perform a wide variety of tasks. For these SMEs, the TailorWeld system offers flexibility thanks to the modular design of the TailorWeld head. The TailorWeld head houses the DOE in a sliding drawer making the exchange of optics fast and simple. The TailorWeld head can be retrofitted onto existing laser systems making it possible for companies who already invested in laser systems to adapt the TailorWeld system. As stated in the DoW, 4000-5000 SMEs have laser cutting equipment which could be retrofitted into laser welding systems.
A major hindrance for the adoption of laser welding is the lack of knowledge about laser welding in industry. There is a shortage of welding engineers with high skill level that can design the process, find suitable parameters and know how different parameter changes affect the process.
The beam delivered by commercial laser system will typically be a top-hat distribution or a Gaussian distribution depending on laser source and the only option for the users to change the distribution is by defocusing which also will alter the spot size and reduce the beam irradiance. With the TailorWeld head and its drawer for DOEs, the user can easily change between DOEs to produce top-hat beam distributions, Gaussian beam distributions or more advanced beam distributions. The TailorWeld DOE design tool will help the end-user to choose a suitable beam distribution and order the correct DOE.
One of the applications studied in the project was multi-spot welding. The method was proven successful and the same optical setup can also be used to achieve multi-spot ablation. The advantage of multi-spot welding in comparison with single spot welding is obvious since each additional spot multiplies the production rate.
The TailorWeld project targeted three different types of SME end-users with one project partner representing each of the groups:
• SMEs with no laser or laser-welding capacity
• SMEs with laser (cutting) capacity but not welding
• SMEs with existing laser welding capability but which can be expanded.
The different categories provided different challenges and solutions:
SMES WITH NO LASER OR LASER WELDING CAPACITY
The example application in this group was an electrical connection which now today is achieved either by soldering or by mechanical fastening. Laser welding, especially with multiple spots, has the potential to change this market by allowing for a higher grade of automation and in the case of multiple spots, a higher throughput rate. DOEs are useful for splitting one beam into several beams especially if it is done in a symmetric pattern.
The TailorWeld head allows for fast changing between beam patterns and the TailorWeld DOE design tool is useful for investigating if the beams are close enough to affect each other. The benefits of a multi-spot system is apparent when considering that moving from one to five simultaneous beams directly cuts the process time in five.
SMES WITH LASER (CUTTING) CAPACITY BUT NOT WELDING
Battery welding was studied in this category. Laser welding has previously been studied in this segment with many potential advantages. In the TailorWeld project, DOEs were used to produce ring-shaped and C-shaped beams for joining battery tabs. Joint integrity and electrical conduction are the main joint properties to take into account. During welding, thermal management is of utmost importance since the batteries can explode if overheated. The DOE design tool helps to keep track of the temperature and also to predict how large the joint area will be.
Laser welding proved to be successful so the SME end-user in the project actually bought a new laser system for welding during the project.
SMES WITH EXISTING LASER WELDING CAPABILITY BUT WHICH CAN BE EXPANDED
One of the SMEs already had knowledge and equipment for laser welding which they used in production. The challenge for them was to laser weld duplex stainless steel and still keep ferrite/austenite ratio similar to the as-received content. The TailorWeld project demonstrated that a tailored beam can enhance the ferrite austenite content considerably rending the use of expensive and complex addition of filler material unnecessary. The Look-up table included in the TailorWeld DOE design tool aids the beam design by predicting the ferrite/austenite content from calculating the temperature profile from a user-designed beam and then calculating the subsequent cooling cycle.
The use of duplex stainless steels is increasing since they exhibit:
• Higher strength than traditional austenitic and ferritic stainless steel grade which in turn allow for more lightweight structures
• Better stress corrosion cracking resistance compared to 304 stainless steel
• Lower price than other stainless steels with comparable features
One of the key barriers preventing more use of Duplex Stainless steel is the more advanced microstructure than austenitic grades which makes it harder to weld and still keeping the desired material properties. Here the results from the TailorWeld project have potential to allow end-users to capitalise on the advantages of Duplex stainless steels far more than today.
DEMONSTRATION
The TailorWeld system was demonstrated at Impact Clean Powers facilities in Warsaw, Poland. The demonstration case was an industrial battery welding case which had not been previously studied in the project. The studied case is today manufactured by laser welding with a galvanometric beam scanner, at the demonstration activity instead a ring-shaped beams was used.
The TailorWeld head with a DOE inserted was demonstrated in ICPs laser welding cell. The galvanometric scanner head usually applied in their production was replaced with the TailorWeld head in order to demonstrate the project results in an industrial setup. The application was welding of a battery pack that was not previously studied in the project. Setup of the hardware proved to be simple and the resulting weld time was successful
At the demonstration activity TWI presented the TailorWeld head, its specifications and its modular design. Results from the industrial SME end-user cases in the project were also shown, as well as the results of the blind tests. The algorithm, structure and equations behind the software were presented to the participants in the Demonstration activity along with screenshots of the GUI. LTU had a live demonstration of the software where it was shown step-by-step how the modelling software can be used and how material data and look-up table data can be modified to make the software useful for more cases than those studied in the project.
The results of the project were disseminated through several channels to raise awareness on the project. The project partners jointly carried out some of the dissemination while some of the dissemination was conducted independently by the partners. Typical technological dissemination of the project was trade fairs and similar while the scientific discoveries was disseminated at conferences and in journal publications.
The project partners together produced seminar material on the TailorWeld system including; design of the TailorWeld head, laser properties, monitoring possibilities and functionality. The industrial welding cases performed in the project were also shown to demonstrate the capabilities of the TailorWeld system including the physical TailorWeld head with different DOEs and the GUI design tool. EWF presented this material in three different industrial training events.
EWF organised the partners to create a flyer with information on the project and what benefits the TailorWeld has.
DISSEMINATION OF SCIENTIFIC RESULTS
The TailorWeld project produced scientific results on tailored beam shapes. The main results of the project was presented at leading laser processing and welding conferences. The conferences where the results was presented is listed below:
• International Congress on Applications of Lasers and Electro-Optics (ICALEO) – Held in San Diego, CA, October 2014. Title: Numerical sensitivity analysis of single pulse laser welding with a C-shaped beam, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Quintino (EWF) Paper #1804 - ICALEO is one of the biggest Conferences in Laser Processing and attracts experts, both from industry and academia. It normally has more than 300 participants from different countries. The presentation of TailorWeld during this conference allowed the participants, from Lulea University, to engage with researchers but also with responsible from different companies.
• Laser Advanced Materials Processing (LAMP) – Held in Kitakyushu, Japan, May 2015. Title: Heat conduction modelling to optimize the laser beam profile for pulsed conduction mode welding, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Quintino (EWF) - As ICALEO, LAMP is also considered one of the main conferences in laser processing of materials, focusing more on companies and industries from Asia is still considered one of the conferences to go for laser processing, allowing a closer engagement with industry and academia.
• International Institute of Welding (IIW) - Melbourne - The IIW Annual Assembly and Conference is the biggest conference in Welding, with more than 600 participants from around the world. By presenting the TailorWeld project in the IIW, presentation carried out by EWF, it was possible to engage with industry and academia.
• Laser Assisted Net-shape Engineering (LANE) – Fuerth - The LANE conference (http://www.lane-conference.org/) is also considered one of the main conference in laser processing, focusing mainly on Net-shaping applications. This allowed showing the capability of the TailorWeld system, to industry and Academia, for fields of application different from the ones tested in the project.
The TailorWeld project was presented in other conferences and events in order to ensure engagement with academia and industry outside of the consortium.
Besides the conferences, some results were also presented in journals. Below are the published articles:
• Journal of Laser Applications, 27(S2), S29010 (7p) - Numerical sensitivity analysis of single pulse laser welding with a C-shaped beam, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Coutinho (EWF)
• Optics and Lasers in Engineering, 79, 48-54 - Numerical optimization approaches of single-pulse conduction laser welding by beam shape tailoring, Authors: J. Sundqvist, A.F.H. Kaplan (LTU), L. Shachaf, A. Brodsky (HOL), C. Kong, J. Blackburn (TWI), E. Assuncao, L. Quintino (EWF)
Some papers are also under development but are not yet published.
• Welding in the World article
• Paper entitled Analytical heat conduction modelling for shaped laser beams will be submitted to Journal of materials processing
The full list of dissemination activities can be found in Deliverable 6.3.
MULTIMEDIA DISSEMINATION
A website about the project was produced at the start of the project and has been running during the duration. The website contains information on the project such as background on the project, the possible opportunities created in the project and how the beam tailoring is solved.
The website also contains News and Events, publications in the project and links to the project partners.
A YouTube video describing the project was produced to provide fast and easily-accessible information on the project.
STANDARDS REVIEW
The TailorWeld consortium produced a document with the purpose of suggesting several modifications to the EN ISO 15609-4 Standard regarding the Welding Procedure Specification (WPS) for laser welding, in order to contemplate certain particularities introduced by TailorWeld.
The following Standards were also analysed and are considered not to conflict with the developments introduced by the TailorWeld project:
• EN ISO 4063:2009
• EN ISO 15607:2003
• ISO 15613:2004
• ISO 15614-11:2002
• EN 10217-7:2005
The suggested changes were produced since the standards only concern welding with standard beam shapes and standard optics which is not directly applicable to the TailorWeld system and a potential barrier to adoption of the TailorWeld system.
TRAINING
The TailorWeld 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 TailorWeld results at an Industrial level training was mandatory. This will also ensure an increase of employability in this area.
POST-PROJECT EXPLOITATION
The project has produced a laser weld system consisting of the TailorWeld optics head, the fibre laser, the control system and modelling software together with the know-how created within the programme. The system was already tested during the Demonstration Event at one of the SME-AG partners in the project. The application was studied with the software before the Demonstration event which meant only small modifications on the pulse time was needed on-site. Setting up the system proved to be simple which should make adoption of the TailorWeld system less risky for SMEs with existing laser sources.
The applications investigated in the TailorWeld project is today solved with other processes, like mechanical fastening, soldering, laser welding with a galvanometric beam scanner or welding with filler material. The TailorWeld system was successful in performing all these tasks with higher throughput rate in comparison to the traditional methods, thanks to the close control of the laser beam and heat input. Being able to solve three very different applications with the TailorWeld system shows great promise for implementation of the system in industry.
As identified in the DoW, one major risk is the high capital cost of fibre laser systems and the fact that fibre lasers were not the most common laser system then. In 2016, Industrial Laser Systems reported that fibre lasers account for 54 % of the total industrial laser market making lowering the risk for adoption of the TailorWeld system. This combined with the work carried out in terms of training and standardization it is clear that the TailorWeld project will have an impact in industry.
More information on the potential impact is given in Deliverable 6.3.
List of Websites:
www.tailorweld.eu
Project Coordinator - Eurico Assunção - egassuncao@isq.pt
Technical Coordinator - Choon Kong - choon.kong@twi.co.uk
Laser beam welding is a high-performance joining process that is rapidly growing. The process offers a low distortion and high performance joining solution, achieving high productivity and consistent welds. The global market for laser systems for materials processing exceeds $10 billion per annum. The laser welding segment accounted for approx. $350 million in 2014 with an annual growth rate of 5%.
Despite these benefits and healthy growth, the uptake of laser welding technology is still limited amongst SMEs, for three related reasons: complexity, lack of flexibility, and difficulties in using lasers for ‘non-standard’ welds. Most existing laser systems are fitted with either a standard process head or a 2D galvanometer scanner. This relatively simplistic energy distribution is not directly suitable for many applications and significant laser welding expertise is often required to develop acceptable processing parameters.
The aim of the TailorWeld project was to develop and demonstrate an innovative laser welding system, which uses simple and robust diffractive optical elements that will increase the flexibility and simplify the application of laser welding. Diffractive optical element (DOE) is widely used in low power applications, generally in the visible wavelength, for applications such as optical interconnections and image processing. Their use in high power laser applications has been mainly limited to beam splitting, beam sampling and Gaussian-to-top hat beam shape conversion.
In order that the SMEs in the TailorWeld project manage the RTDs’ worked to deliver these benefits, the TailorWeld project had a series of Scientific, Technical, and Validation objectives.
Scientific objectives:
1. Generate detailed data on laser welding with tailored energy distributions for the three most industrially relevant materials and three typical joint combinations in the target markets.
Consequently, it was able to develop WPS (to ISO 15614) for three end-user applications, by end of month 15 of the project.
2. Produce validated thermo-physical semi-analytical models for conduction limited and keyhole laser welding by month 18 of the project, which is capable of modelling the resulting weld shape for end-user specified joints; applicable for the range of materials and joints specified in Objective 1.
Technical objectives:
3. Using the results of Objective 1, produce, test and validate a series of DOEs, which enabled the three end-user applications specified by ICP, HAL and GRA, by month 20 of the project.
4. By month 27 of the project, design and prototype a DOE laser welding head module which: allows the easy interchanging of DOEs, can integrate with commercially available laser welding process heads, and incorporates co-axial process monitoring for Quality Assurance purposes.
5. Using the result of Objective 2, by month 27 of the project, develop a DOE design tool which uses the semi-analytical models, is able to access look-up tables and numerical model data, and has a bespoke GUI to enable specification of energy distributions from the model for end-user specified joints in less than thirty minutes.
Validation objectives:
6. Integrate the DOE laser welding head module into a laser welding head(s) and laser source, and perform demonstrations of laser welding using the TailorWeld system at at-least one end-user SME site. Demonstrating the same productivity improvements as Objective 3 by month 31 of the project.
7. Perform a detailed techno-economic analysis of the results, in terms of weld quality and properties, for at least 3 different end-user requirements, were presented as case-studies to compare tailored energy distributions to existing methods, including full operating cost analysis, by end of the project.
At the end of the TailorWeld Project all of these objectives were achieved, demonstrating the success of the project.
Project Context and Objectives:
Laser beam welding is a high-performance joining process that is rapidly growing. High power lasers to a value of ~$440M were sold in 2015 meaning a growth by 17% from 2014. The reason for the sales growth of high power lasers can be attributed to developments in laser welding technologies providing a higher availability of fibre delivered Yb:YAG fibre lasers, Yb:YAG disc lasers and direct diode lasers. These new type of lasers have several benefits in comparison with CO2-lasers:
• Up to five times higher lifetime
• Beam switching making it easier to use one laser source for several work stations
• Fibre-guided beams which provides more stable beam delivery than mirror systems
• 3-4 times higher wall-plug efficiency
• Less service required
• No gas needed to create the laser beam
Despite this, mostly large enterprises have adopted laser welding. Among SMEs laser welding is still limited due to the following reasons:
• High initial investment cost (albeit the cost is decreasing)
• Complexity of setting up a laser welding system
• Complexity in finding good welding parameters and maintaining the system, very few laser welding engineers available
• Difficult to use for non-standard welds
At the start of the project EWF estimated that ~8000 of their members could significantly boost their competitiveness if they had access to a flexible laser welding process; either by retrofitting existing laser cutting equipment or by acquiring a new laser welding system.
Traditionally, rotationally symmetric laser beams with Gaussian-like or top hat-like profiles are used for welding since these are the beam-intensity profiles often generated by high power laser sources, particularly when the beam is guided by an optical fibre to the work-piece. The beam is then delivered onto the workpiece with a standard process head or a 2D galvanometric scanner. The Gaussian-like or top-hat like distributions are simplistic and not directly suitable for all applications which make finding the right parameters cumbersome and complex.
The TailorWeld concept aim is stated as:
“To develop and demonstrate an innovative laser welding system, that uses simple and robust diffractive optical elements (DOEs), which will increase the flexibility and simplify the application of laser welding; removing the key barrier to entry for SME fabricators”
To achieve this aim, a welding head incorporating a DOE must be designed so that SMEs easily can use DOEs and change between them for different manufacturing operations making their laser welding process flexible. The laser welding head should be easy to use to avoid having operators go through advanced training.
The companies that uses DOEs today usually decide on their DOEs through a trial-and-error approach, i.e they order an optic which they think will be suitable and if it does not work they order a new one. This quickly becomes expensive and time-consuming. TailorWeld will alleviate this problem with the development of a fast thermo-physical model that will be accessible through a Garphical User Interface. The model allows the SME end-users to quickly investigate the resulting joints from different beam profiles. These types of simulations can also be performed by commercial numerical software codes but they require expertise and the licensing costs are often high. The TailorWeld project instead aims at a fast license-free software that is easy to use. The modelling codes are simpler than the numerical codes but will be compared to numerical modelling during the project to assure that no key effects are missed.
DIFFRACTIVE OPTICAL ELEMENTS AND POTENTIAL BENEFITS
DOEs is a new method for controlling a laser beam in laser materials processing. The first one was made by the project partner HOLO/OR in 1991. DOEs have several beneficial properties:
• Can produce almost any energy distribution
• Robust, no moving parts
• Low cost
• Reduces the requirement for specialist laser welding operators
However DOEs are seldom used in industry because of the earlier mentioned complexities regarding beam design.
SMEs benefits from the TailorWeld system through:
• Replacement of expensive galvanometer systems with low-cost DOEs
• A low cost system for producing tailored energy distributions together with a tool to predict a suitable energy distribution
• A DOE laser welding head module which can be used on a new system or retro-fitted onto an existing system
• Built in process monitoring
• A processing head that allows for fast change of DOEs to allow for flexible production.
The TailorWeld system also enhances the performance of:
• Joining of dissimilar materials by compensating for different thermal properties
• Welding of crack-sensitive and phase sensitive materials through better thermal management by including several beams
• Multi-spot welding. Instead of doing multiple single-spot welds, the TailorWeld system allows for making one multi-spot weld.
POSSIBLE TECHNICAL BARRIERS
At the start of the project several technical barriers were identified and subsequently solved during the project:
1. Tailored energy distributions for envisaged new laser welding applications are not optimised:
This was overcome by studying welding with non-standard beam shapes through laser welding experiments with different materials and joint setups. The experiments were complemented with High-Speed Imaging to capture fluid flow effects and with thermal camera to study the temperature profile and cooling rates. The experiments are concentrated on the three applications chosen by the end-user SMEs in the project.
2. Current approach for producing tailored energy distributions is through trial-and-error which is not cost effective for end-users
Experimental results from 1 were used to validate the numerical models and in turn the fast semi-analytical models which are the base for the DOE design tool.
3. DOE laser welding head module with in-built process monitoring does not exist
A laser welding head that allows for fast interchange between DOEs was designed and a prototype manufactured.
4. Limited data on laser welding with DOEs for envisaged new welding applications
Welding experiments were conducted systematically and compared to competing processes
OBJECTIVES
The TailorWeld consortium established a number of objectives that needed to be fulfilled in order to deliver the TailorWeld system to the market. These objectives were divided into three phases. “Research phase”, “Technology Development Phase” and “Validation and Demonstration phase”
Research: The state-of-the-art on welding with non-standard beam shapes contained little information so the project had to generate data from experiments by monitoring the experiments and analysing cross-sections. Modelling and simulation was used to produce complimentary data.
Research: Very few mathematical models concerning welding with non-standard beam shapes existed before the project, particularly fast semi-analytical models. Thus the TailorWeld had to produce these models and validate them with experiments.
Technology: DOEs for the three end-user applications had to be produced and validated. The DOEs should decrease the weld time with at least 50 %.
Technology: Design and develop the earlier mentioned laser welding head with interchangeable DOEs and built-in process monitoring
Technology: Build a GUI that can access the semi-analytical models and use look-up tables to account for other effects. The calculation time should be shorter than 30 minutes.
Dissemination: Integrate the TailorWeld head in an existing laser system at one of the SME end-users and do a demonstration event.
Dissemination: Perform a techno-economic analysis of the results with regards to weld quality, weld properties and cost with existing technologies.
The main objectives of the TailorWeld project, can be divided into scientific and technological as well into dissemination and exploitation activities, which were held to spread the findings of the project and to ensure the uptake by industry. Despite the steady increase in sales of laser welding equipment, the uptake of laser welding in European SMEs is small due to complexity and the costs associated with it. By not adopting laser welding, there is a risk that the European SMEs may lose competitiveness. Laser weld systems typically deliver a Gaussian beam or a top-hat beam which sometimes is too simplistic. Diffractive Optical Elements (DOE) can be used to shape the beam to almost any profile making it possible to weld products where the standard beam shapes are not directly suitable. The aim of the TailorWeld project was to develop a complete laser welding system with a laser welding head incorporating a DOE and complementing easy-to-use software to calculate suitable energy distributions. The TailorWeld system targets SMEs and the goal is to remove the complexity barrier to allow for more SMEs to adopt laser welding.
The project had to make scientific and technological progress in order to fulfil these goals. Welding with non-standard beam shapes had been scarcely studied before the project particularly for DOEs. The project started out with categorising welding with tailored beams on three SME end-user applications defined in the project.
Concurrently two fast semi-analytical models for different welding modes (keyhole mode and conduction mode) were developed based on experiments and numerical modelling (published in scientific journals). Look-up tables that describe effects based on temperature were also developed to supplement the semi-analytical models.
The experiments on the end-user applications showed that DOEs could produce beneficial results in all three cases mainly by shortening weld cycle time. A laser welding head with a cartridge system for fast interchange between DOEs was developed. The welding head can be used on new laser systems or retro-fitted onto existing laser systems.
A DOE design tool with a GUI was developed to enable easy access to the semi-analytical models. The design tool also provides access to the look-up tables to study special welding effects. One of the applications considers welding with Duplex stainless steel, thus the design tool can predict the resulting ferrite/austenite ratio. The tool was designed with the three end-user cases in focus but additional materials were included in the software. The material data and look-up tables were stored in a text-file allowing users to add/modify materials and look-up criteria.
The TailorWeld head was installed at one of the end-user SMEs. Their galvanometric scanner was replaced with the TailorWeld head. The resulting weld was successful and reduced the weld cycle time. Installation and validation time was swift and successfully accomplished in just a few hours.
The TailorWeld consortium suggested several modifications to the EN ISO 15609 Standard regarding the Welding Procedure Specification (WPS) based on findings in the project to allow for tailored energy distributions.
The consortium also targeted training, through several routes, in order to ensure that companies interested in using the TailorWeld system will have access to trained staff.
Scientific results from the project have been presented in scientific journals and international conferences. In addition material has also been prepared for post-project dissemination in both scientific journals and at international conferences. Technological achievements have been presented at seminars, trade fairs, partner websites and a YouTube video was made explaining the project and its potential benefits.
Project Results:
See attachment - Appendix 1
See attachment for some of the dissemination materials
Additional information regarding WP 4:
Reparding the report on DOE design tool and GUI the consortium ended up extending the work carried out in WP 4 (responsible for the DOE design tool and GUI) for some more months, not because of delays, but to ensure that the results and tests from WP 5 could be fed into WP 4 to improve the results based on feedback from the end users. We discussed this with the PO and she approved our requests (please have a look at the emails in attachment). Based on this exchange and considering that D4.1 D4.2 and D4.3 were submitted correctly we believed that this would suffice and our email exhange with the PO made us believe that no report was needed since we did report, by email, the progress of WP4. Mainly, because, what was a risk identified by the reviewer and PO, due to the short time, ended up not causing any delay in the project and the consortium was able to deliver all the results identified at the beginning of the project. Adding to this, the requested report, at this time would pretty much be the same as what was reported in D4.1 D4.2 and D4.3 and the extra time was mainly used to improve the software and not to develop it.
However, in order to provide a clearer idea of the status of WP4 at M22, some more information is given bellow:
In M22 the GUI was practically finished and working but it had not been bug tested or tested for stability meaning that it still was in an early state, work on D4.2 and D4.3 was more harmonised and worked on together instead of worked on sequentially. An extension of the delivery date was asked for because of the following reasons:
• To be able to bug test the software more, which was mostly done in-house at LTU by other laser welding experts who had not been part in development of the software.
• To receive input from the end-users and be able to change the software accordingly. Training for the design tool was performed at the M24 meeting in Tel Aviv to identify possible flaws in the software regarding user-friendliness and to give end-users time to evaluate the software. The M24 was also used to get more feedback from the end-users, for example different choices of visualisations (2D or 3D) were presented to the project partners to see which detail of visualisation was desired. On this meeting it was also decided that LTU develop a user guideline to make sure that new users can use the software without expert support after the project ends.
• Use results from WP5 to further improve the software. The software was used on the WP5 experiments to test the software for real application cases. Also experimental results were used to further validate the software with the keyhole-mode model together with the look-up table for the GRA case.
Potential Impact:
The TailorWeld system has large potential as more and more European companies replaces their conventional welding equipment with laser welding equipment as the price of laser power sources decreases. A switch from arc welding to laser welding gives higher productivity, higher controllability and a smaller heat affected zone. Less heat input and smaller heat affected zones results in faster cooling which can be a drawback in crack-susceptible materials. Here the TailorWeld system could be used to incorporate pre- or post-heating in the process instead of having to do it in another process. LTU recently presented that laser remelting of welds created by laser-arc welding can create smoother weld geometry which can enhance fatigue life since surface geometry usually have a detrimental effect on it. The remelting was achieved by defocusing the beam and doing one more run over the weld. With the the Tailorweld system this could be done in only one run and the process would use less energy since the weld would not cool before the remelting beam. These two examples are just some of many potential applications where the TailorWeld system could provide benefits in comparison to traditional welding processes and existing laser welding solutions.
The TailorWeld project demonstrated the use of similar multi-beam optics in a case where the target was to achieve a 50/50 ferrite/austenite balance after welding by applying a post-processing beam. The balance between ferrite/austenite is mainly governed by the cooling cycle but can also be altered by shielding gas or added material. Achieving the desired balance is probably impossible by only using a standard laser beam but the TailorWeld head gives opportunity to tailor the cooling cycle in many ways. However the head is not enough since it is complex to correctly predict the desired beam shape. Here the DOE design tool is useful to avoid doing costly experiments. The complete TailorWeld system thereby creates new opportunities for laser welding.
Many SMEs, especially sub-contract firms, demands flexible machines and equipment to be able to perform a wide variety of tasks. For these SMEs, the TailorWeld system offers flexibility thanks to the modular design of the TailorWeld head. The TailorWeld head houses the DOE in a sliding drawer making the exchange of optics fast and simple. The TailorWeld head can be retrofitted onto existing laser systems making it possible for companies who already invested in laser systems to adapt the TailorWeld system. As stated in the DoW, 4000-5000 SMEs have laser cutting equipment which could be retrofitted into laser welding systems.
A major hindrance for the adoption of laser welding is the lack of knowledge about laser welding in industry. There is a shortage of welding engineers with high skill level that can design the process, find suitable parameters and know how different parameter changes affect the process.
The beam delivered by commercial laser system will typically be a top-hat distribution or a Gaussian distribution depending on laser source and the only option for the users to change the distribution is by defocusing which also will alter the spot size and reduce the beam irradiance. With the TailorWeld head and its drawer for DOEs, the user can easily change between DOEs to produce top-hat beam distributions, Gaussian beam distributions or more advanced beam distributions. The TailorWeld DOE design tool will help the end-user to choose a suitable beam distribution and order the correct DOE.
One of the applications studied in the project was multi-spot welding. The method was proven successful and the same optical setup can also be used to achieve multi-spot ablation. The advantage of multi-spot welding in comparison with single spot welding is obvious since each additional spot multiplies the production rate.
The TailorWeld project targeted three different types of SME end-users with one project partner representing each of the groups:
• SMEs with no laser or laser-welding capacity
• SMEs with laser (cutting) capacity but not welding
• SMEs with existing laser welding capability but which can be expanded.
The different categories provided different challenges and solutions:
SMES WITH NO LASER OR LASER WELDING CAPACITY
The example application in this group was an electrical connection which now today is achieved either by soldering or by mechanical fastening. Laser welding, especially with multiple spots, has the potential to change this market by allowing for a higher grade of automation and in the case of multiple spots, a higher throughput rate. DOEs are useful for splitting one beam into several beams especially if it is done in a symmetric pattern.
The TailorWeld head allows for fast changing between beam patterns and the TailorWeld DOE design tool is useful for investigating if the beams are close enough to affect each other. The benefits of a multi-spot system is apparent when considering that moving from one to five simultaneous beams directly cuts the process time in five.
SMES WITH LASER (CUTTING) CAPACITY BUT NOT WELDING
Battery welding was studied in this category. Laser welding has previously been studied in this segment with many potential advantages. In the TailorWeld project, DOEs were used to produce ring-shaped and C-shaped beams for joining battery tabs. Joint integrity and electrical conduction are the main joint properties to take into account. During welding, thermal management is of utmost importance since the batteries can explode if overheated. The DOE design tool helps to keep track of the temperature and also to predict how large the joint area will be.
Laser welding proved to be successful so the SME end-user in the project actually bought a new laser system for welding during the project.
SMES WITH EXISTING LASER WELDING CAPABILITY BUT WHICH CAN BE EXPANDED
One of the SMEs already had knowledge and equipment for laser welding which they used in production. The challenge for them was to laser weld duplex stainless steel and still keep ferrite/austenite ratio similar to the as-received content. The TailorWeld project demonstrated that a tailored beam can enhance the ferrite austenite content considerably rending the use of expensive and complex addition of filler material unnecessary. The Look-up table included in the TailorWeld DOE design tool aids the beam design by predicting the ferrite/austenite content from calculating the temperature profile from a user-designed beam and then calculating the subsequent cooling cycle.
The use of duplex stainless steels is increasing since they exhibit:
• Higher strength than traditional austenitic and ferritic stainless steel grade which in turn allow for more lightweight structures
• Better stress corrosion cracking resistance compared to 304 stainless steel
• Lower price than other stainless steels with comparable features
One of the key barriers preventing more use of Duplex Stainless steel is the more advanced microstructure than austenitic grades which makes it harder to weld and still keeping the desired material properties. Here the results from the TailorWeld project have potential to allow end-users to capitalise on the advantages of Duplex stainless steels far more than today.
DEMONSTRATION
The TailorWeld system was demonstrated at Impact Clean Powers facilities in Warsaw, Poland. The demonstration case was an industrial battery welding case which had not been previously studied in the project. The studied case is today manufactured by laser welding with a galvanometric beam scanner, at the demonstration activity instead a ring-shaped beams was used.
The TailorWeld head with a DOE inserted was demonstrated in ICPs laser welding cell. The galvanometric scanner head usually applied in their production was replaced with the TailorWeld head in order to demonstrate the project results in an industrial setup. The application was welding of a battery pack that was not previously studied in the project. Setup of the hardware proved to be simple and the resulting weld time was successful
At the demonstration activity TWI presented the TailorWeld head, its specifications and its modular design. Results from the industrial SME end-user cases in the project were also shown, as well as the results of the blind tests. The algorithm, structure and equations behind the software were presented to the participants in the Demonstration activity along with screenshots of the GUI. LTU had a live demonstration of the software where it was shown step-by-step how the modelling software can be used and how material data and look-up table data can be modified to make the software useful for more cases than those studied in the project.
The results of the project were disseminated through several channels to raise awareness on the project. The project partners jointly carried out some of the dissemination while some of the dissemination was conducted independently by the partners. Typical technological dissemination of the project was trade fairs and similar while the scientific discoveries was disseminated at conferences and in journal publications.
The project partners together produced seminar material on the TailorWeld system including; design of the TailorWeld head, laser properties, monitoring possibilities and functionality. The industrial welding cases performed in the project were also shown to demonstrate the capabilities of the TailorWeld system including the physical TailorWeld head with different DOEs and the GUI design tool. EWF presented this material in three different industrial training events.
EWF organised the partners to create a flyer with information on the project and what benefits the TailorWeld has.
DISSEMINATION OF SCIENTIFIC RESULTS
The TailorWeld project produced scientific results on tailored beam shapes. The main results of the project was presented at leading laser processing and welding conferences. The conferences where the results was presented is listed below:
• International Congress on Applications of Lasers and Electro-Optics (ICALEO) – Held in San Diego, CA, October 2014. Title: Numerical sensitivity analysis of single pulse laser welding with a C-shaped beam, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Quintino (EWF) Paper #1804 - ICALEO is one of the biggest Conferences in Laser Processing and attracts experts, both from industry and academia. It normally has more than 300 participants from different countries. The presentation of TailorWeld during this conference allowed the participants, from Lulea University, to engage with researchers but also with responsible from different companies.
• Laser Advanced Materials Processing (LAMP) – Held in Kitakyushu, Japan, May 2015. Title: Heat conduction modelling to optimize the laser beam profile for pulsed conduction mode welding, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Quintino (EWF) - As ICALEO, LAMP is also considered one of the main conferences in laser processing of materials, focusing more on companies and industries from Asia is still considered one of the conferences to go for laser processing, allowing a closer engagement with industry and academia.
• International Institute of Welding (IIW) - Melbourne - The IIW Annual Assembly and Conference is the biggest conference in Welding, with more than 600 participants from around the world. By presenting the TailorWeld project in the IIW, presentation carried out by EWF, it was possible to engage with industry and academia.
• Laser Assisted Net-shape Engineering (LANE) – Fuerth - The LANE conference (http://www.lane-conference.org/) is also considered one of the main conference in laser processing, focusing mainly on Net-shaping applications. This allowed showing the capability of the TailorWeld system, to industry and Academia, for fields of application different from the ones tested in the project.
The TailorWeld project was presented in other conferences and events in order to ensure engagement with academia and industry outside of the consortium.
Besides the conferences, some results were also presented in journals. Below are the published articles:
• Journal of Laser Applications, 27(S2), S29010 (7p) - Numerical sensitivity analysis of single pulse laser welding with a C-shaped beam, Authors: J. Sundqvist (LTU), Alexander F. H. Kaplan (LTU), Choon-Yen Kong (TWI), Jon Blackburn (TWI), Eurico Assunção (EWF), L. Coutinho (EWF)
• Optics and Lasers in Engineering, 79, 48-54 - Numerical optimization approaches of single-pulse conduction laser welding by beam shape tailoring, Authors: J. Sundqvist, A.F.H. Kaplan (LTU), L. Shachaf, A. Brodsky (HOL), C. Kong, J. Blackburn (TWI), E. Assuncao, L. Quintino (EWF)
Some papers are also under development but are not yet published.
• Welding in the World article
• Paper entitled Analytical heat conduction modelling for shaped laser beams will be submitted to Journal of materials processing
The full list of dissemination activities can be found in Deliverable 6.3.
MULTIMEDIA DISSEMINATION
A website about the project was produced at the start of the project and has been running during the duration. The website contains information on the project such as background on the project, the possible opportunities created in the project and how the beam tailoring is solved.
The website also contains News and Events, publications in the project and links to the project partners.
A YouTube video describing the project was produced to provide fast and easily-accessible information on the project.
STANDARDS REVIEW
The TailorWeld consortium produced a document with the purpose of suggesting several modifications to the EN ISO 15609-4 Standard regarding the Welding Procedure Specification (WPS) for laser welding, in order to contemplate certain particularities introduced by TailorWeld.
The following Standards were also analysed and are considered not to conflict with the developments introduced by the TailorWeld project:
• EN ISO 4063:2009
• EN ISO 15607:2003
• ISO 15613:2004
• ISO 15614-11:2002
• EN 10217-7:2005
The suggested changes were produced since the standards only concern welding with standard beam shapes and standard optics which is not directly applicable to the TailorWeld system and a potential barrier to adoption of the TailorWeld system.
TRAINING
The TailorWeld 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 TailorWeld results at an Industrial level training was mandatory. This will also ensure an increase of employability in this area.
POST-PROJECT EXPLOITATION
The project has produced a laser weld system consisting of the TailorWeld optics head, the fibre laser, the control system and modelling software together with the know-how created within the programme. The system was already tested during the Demonstration Event at one of the SME-AG partners in the project. The application was studied with the software before the Demonstration event which meant only small modifications on the pulse time was needed on-site. Setting up the system proved to be simple which should make adoption of the TailorWeld system less risky for SMEs with existing laser sources.
The applications investigated in the TailorWeld project is today solved with other processes, like mechanical fastening, soldering, laser welding with a galvanometric beam scanner or welding with filler material. The TailorWeld system was successful in performing all these tasks with higher throughput rate in comparison to the traditional methods, thanks to the close control of the laser beam and heat input. Being able to solve three very different applications with the TailorWeld system shows great promise for implementation of the system in industry.
As identified in the DoW, one major risk is the high capital cost of fibre laser systems and the fact that fibre lasers were not the most common laser system then. In 2016, Industrial Laser Systems reported that fibre lasers account for 54 % of the total industrial laser market making lowering the risk for adoption of the TailorWeld system. This combined with the work carried out in terms of training and standardization it is clear that the TailorWeld project will have an impact in industry.
More information on the potential impact is given in Deliverable 6.3.
List of Websites:
www.tailorweld.eu
Project Coordinator - Eurico Assunção - egassuncao@isq.pt
Technical Coordinator - Choon Kong - choon.kong@twi.co.uk