Laurent Dubourg the co-founder and the CEO of Stirweld, a deep-tech created in 2017 with the aim to democratize Friction Stir Welding all around the world.

He worked as an R&D engineer at IREPA Laser for five years in developing laser cladding and additive manufacturing processes for automotive applications. Then Laurent did a PhD thesis on 'Laser cladding of aluminium substrate and the development of the associated metallurgical coatings' at the National Research Council of Canada. At the CNRC, he was responsible for Friction Stir Welding – FSW Program development and laser welding applications.

AlCircle: Stirweld was founded in 2017 based on Friction Stir Welding (FSW). What has been your journey to success in the world of technology?

Laurent Dubourg: Indeed, Stirweld was created in 2017 with the ambition of democratizing friction stir welding, which was previously reserved for high value-added applications due to its investment cost.

But with our flagship product, our FSW welding head for CNC, we have broken the codes of the market by proposing equipment ten times cheaper than a special FSW machine. So we open up the market to new applications, to new companies.

To do this, we have grown from 4 people in 2017 to 22 people in 2022. Our team consists of highly qualified members in their field: IWE welding engineers, research and development, marketing, sales, automation, and manufacturing. A complementary, multidisciplinary, multicultural team is the strength of Stirweld today.

Thanks to our agility and flexibility, in 5 years, we have grown by adapting to the codes of our target markets and the industry codes.

I think our strength lies in the flexibility and agility of our team, its qualifications and the multicultural and multi-generational nature of the team.

AlCircle: In what ways does Stirweld's technology relate to digital transformation in the aluminium industry?

Laurent Dubourg: Our FSW welding head for CNC and FSW spindle for robot technology is fully integrated with the digital transformation of the aluminium industry. Our products are now equipped with a real intelligence system (HMI) to collect welding data (force control, temperature control and measurement, vibrations etc.). This system enables predictive maintenance, permitting fluid and accessible communication between the user and the FSW equipment via visual and audible alerts. But the key advantage of this intelligent system is the information feedback. Indeed, thanks to this complete instrumentalisation of our FSW equipment, the HMI is able to provide a large amount of information in full monitoring: torque measurement, welding torque, vibrations, inclinations, and cooling. All this information makes it possible to improve the quality and efficiency of the various FSW welding series and to ensure that the weld bead runs smoothly on the various assemblies.

AlCircle: Is aluminium and the energy-efficient FSW contributing to reducing global warming?

Laurent Dubourg: Yes, friction stir welding helps to reduce global warming. It can indeed be called a green process. It is a technology that does not emit fumes, gases or anything else. Unlike other welding technologies, FSW does not require surface preparation of the parts and does not involve any prior stripping.

In addition, because FSW is a cold welding process, no filler material is used, and no toxic gases, UV radiation or electromagnetic fields are applied.

Also, as is well known, aluminium is an infinitely recyclable material but can be difficult to weld and was, therefore, not favoured for certain industrial parts. With the advent of FSW, this is no longer the case. Indeed, FSW has made it possible to weld any aluminium alloy, including high-strength aluminium. As a result, many industries such as the aerospace, automotive and railway industries are turning to aluminium for their parts.

These industries that turn to aluminium and, therefore, to FSW to assemble their parts are industries that are identified as polluting and that will have to comply with quotas and limitations on greenhouse gas emissions. As a result, they are now looking for solutions to offset these quotas and limitations by developing clean means of transport. This is the advent of electricity and hydrogen. In this field, aluminium is used extensively for cold plates, tanks, wind turbine blades etc. And what is the most efficient technology to assemble these parts? FSW, which allows the mechanical properties of the base material to be maintained, a perfect seal and 100% quality control.

AlCircle: What is the key to understand the innovative process for aluminium welding?

Laurent Dubourg: Friction stir welding is a simple and easy-to-learn process. It can be broken down into four main steps:

1. The parts to be welded are clamped in the machine,
2. The tool, consisting of a shoulder that heats the material by friction and a pin that stirs the material, is set in rotation and plunges vertically into the material,
3. The tool moves along the workpieces stirring the material in order to perform the welding operation thanks to the heat generated by the friction, which makes the material more flexible,
4. The tool moves vertically upwards, leaving an exit hole unless a retractable piece is used.

The parameters to be considered for quality FSW welding are the tool geometry, the vertical FSW load (kN), the welding speed (mm/min) and the rotational speed (rpm).

With our FSW head for CNC and FSW spindle for robot solutions, the learning curve is even easier as we use the control panel of our customer's CNC or robot. In addition, we offer a 3-day FSW training course and support to industrialize the process at our customer's site, including part codesign, clamping design and manufacture and definition of FSW welding parameters. Thus, as our goal is to democratize FSW, we offer regular webinars on FSW, its applications and its trends. Webinars that can be replayed at any time on our website.

AlCircle: In terms of technology and expansion, what new plans does Stirweld have for the current fiscal year?

Laurent Dubourg: We have recently released two new welding equipment:

1. The FSW spindle for the robot
2. The FSW head with a retractable pin

These two types of equipment will serve industries such as automotive, which produces a large volume of parts, but also aeronautics which has a great need for part rigidity and, therefore, to eliminate the exit hole, made possible by the retractable pin.

In addition, we are committed to developing the intelligence of our FSW equipment. Therefore, in a continuous improvement process, we are going to intensify our efforts concerning the automation and the intelligence of our machines with, in particular, the upcoming release of a Smart FSW head for CNC.

And a big step forward for us is opening a subsidiary in the United States at the end of 2022. Indeed, we want to get closer to our American customers to facilitate exchanges and have technical support on the spot.

AlCircle: Who are your major customers? Why do you think FSW can dramatically impact your customer's business?

Laurent Dubourg: Our main customers are Airbus, Ariane, Airbus and Thales, significant companies in the automotive, aeronautics and aerospace industries, where FSW represents a major advance.

Indeed, in the automotive sector and with the development of e-mobility, the use of aluminium is constantly increasing. By 2030, the automotive industry will have changed completely, as a vehicle will have to emit only 59g/km of CO2 compared to 95g/km today. So the preferred solution for the moment is the electric car. An electric car requires batteries and, therefore, an ultra-efficient cooling system while at the same time reducing the weight of the vehicle. The solution: heat sinks in aluminium die casting. And the most suitable, cheapest and 100% quality-assured solution is friction stir welding.

Friction stir welding is, therefore a real breakthrough technology for the automotive industry. This process improves the mechanical strength of aluminium castings with 100% sealing, allows the assembly of more complex parts and ensures the thermal conductivity of the parts. All this while meeting the challenges of this sector: reducing costs, CO2 emissions and ensuring the quality of vehicles.

In the space and aeronautics industry, they face many challenges: reduction of assembly time, weight and cost savings, quality improvement, simplification of the manufacturing process, increase in the life cycle and reduction of the environmental impact and CO2 emissions. One of the answers to these challenges is using aluminium, as it increases the payload and fuel efficiency of aircraft. However, assembling aluminium using conventional welding techniques results in numerous defects. On the contrary, FSW offers many advantages: perfect sealing, superior mechanical strength, longer life due to improved fatigue resistance, easy replacement of MIG and TIG, which are more expensive technologies than FSW, and replacement of riveting, thus saving weight, cost, time and sealing.

These advantages have led to a wide range of applications:

• Cryogenic hydrogen tank assembly
• Panel and fuselage assembly
• Floor assembly
• Raw material reduction,
• Copper component welding

Faster, lower cost and better quality parts contribute to reducing buy-to-fly.

AlCircle: In which market does your solution bring the best ROI? For which market is your solution best suited?

Laurent Dubourg: A particular winner when it comes to FSW is the field of thermal management. And this field is present in all industries, whether it is aeronautical, space, telecommunications, wind turbines, automotive, and many others. For industries such as these, the thermal management of their equipment must be impeccable. Their equipment, such as wind turbines or vehicle batteries, is equipped with liquid cold plates to achieve this. These parts, usually made of aluminium, copper or steel, cool the batteries of industrial equipment. They consist of a housing with a cooling channel covered by a cover fixed to the housing. The best way to assemble this cover today is friction stir welding.

Indeed, welding liquid cold plate by FSW represents several advantages and allows having a high-quality part at a controlled cost:

• Lower cost: replacing EBW or vacuum brazing, two welding processes with a higher production cost than FSW due to the cover and the machine investment.
• Higher resistance: after the pressure resistance test, we could actually see that our FSW welded liquid cold plate resisted up to more than 250 bars.
• Perfectly waterproof: there are no porosities on the surface or inside the part, and there is no sticking.
• Excellent thermal conductivity (metallurgical junction)
• Extremely user-friendly compared with EBW or vacuum brazing.