Robotic rethink for weld inspection

A new robot-based approach to inspecting safety-critical welds for nuclear fabrications could be safer, less obstructive, and offer higher performance than established techniques.

Since summer 2020, the Nuclear AMRC has worked with Cumbrian technology development company Createc to develop and test a robotic system for safely inspecting welds with minimal disruption to production. Funded by BEIS through the advanced manufacturing and materials competition of the Nuclear Innovation Programme, the Mobile Weld Computed Tomography (MWCT) project aimed to improve the safety and performance of weld radiography. This is an essential inspection technique for many welds in safety-critical assemblies in a variety of industries, and will be vital for the development and production of new designs of small and advanced reactor.

However, the health safeguards required for the intense x-rays used in radiography mean that inspection can be a bottleneck in production.

“The current techniques for radiographic inspection are limited in the sense they are very proscriptive – either you have to take your workpiece to a specific place, or get all the people out of the workshop to carry out the radiography,” Etienne Hocquard, head of robotics at Createc, told delegates at a webinar to share the results of the project.

“We thought we could do this differently – how can we use robots to use CT scanning directly on the workpiece, without disrupting the production line?”

Createc’s approach uses a pair of collaborative robots positioned either side of the welded workpiece. One carries an x-ray source; the other carries a CCD image sensor to capture x-ray transmission and an off-the-shelf 3D scanner.

The CCD sensor is very cost-effective compared with a standard CT scanner, Hocquard noted, with a 20-micron resolution which is good enough for any significant weld flaw.

From the control point of view, the main challenges were in synchronising the movement of the two robots, and avoiding collisions with the workpiece and surroundings. “Collaboration of the system is absolutely essential, as is alignment of the workpiece with the parameters of the robots,” Hocquard said. “You need to be very accurately positioned.”

Initial tests on thin metal samples have proven the feasibility of the approach, with the next stage of research aiming to produce data from thicker weld samples produced by the Nuclear AMRC.

The centre’s welding team designed a series of test coupons for the project, featuring intentionally flawed welds of 10–15mm depth in stainless and carbon steels.

To benchmark the performance of the Createc system, all the coupons have been analysed using a CT chamber and a selection of ultrasonic NDT techniques. John Crossley, head of non-destructive testing for the Nuclear AMRC, then compared the results from all the different technologies across all standard flaw dimensions, finding only very minor variations between techniques. These coupons are available for any other technology developers who want to test innovative weld inspection techniques, he noted.

Trialling the MW-CT system on these thicker welds will require a more powerful x-ray source than the 130kV source used in the initial tests, but the team are now preparing proposals for ongoing development.

“We have learned a great deal, and know exactly that the next step will be,” Hocquard said. “That’s why we do innovation.”

The project also involved  workington based TSP Engineering, a member of the Nuclear AMRC, as industrial partner and host for the trials.

Collaborative work: the prototype MW-CT system, with twinned robots carrying an x-ray source and sensor array.
Matt Mellor, CEO, Createc

Matt Mellor, Managing Director

Matt Mellor started his career as an academic working in research and development at Oxford University where his specialist field was in computer vision and robotics with medical application. But in writing papers, which he says were mainly “read by other academics so they could cite it in their research”, Matt could see there was a vital component missing.

“To turn that research into a product I learned that you have got to make that happen yourself to ensure others recognise the value of it,” said Matt. “That started me on an odyssey to learn about the full process of technological development. That means not just learning about technology, but also about business, people, finance – all the parts you need to make something happen which is going to make a positive change in the world.”

With that in mind, Matt moved to Cumbria and joined REACT Engineering. “REACT put the emphasis on entrepreneurship and I joined the company to apply what I had learned in nuclear medicine to nuclear engineering.” In particular, Matt was able to apply his knowledge in medical imaging to provide smart, technological solutions to the nuclear clean-up industry.

In 2007, Matt was the technical lead in setting up REACT’s own spin-out – aerial surveying company, Hi-Def, which gave him valuable experience of the process involved in setting up a spin-out business. Hi-Def went on to be a sustainable, successful business in its own right and in 2016 became part of the BioConsult SH group. Meanwhile, Matt set up Createc in June 2010, and as CEO has led the company to achieve impressive growth ever since.

Createc started out with just three members of staff – Matt, Alan Shippen and Pete Rodgers. The company’s mission was to create a profitable business out of computer vision and robotics research and development, demonstrating the value such a service adds to industry. Building on technological expertise in the nuclear sector learned from REACT Engineering, Createc developed its N-Visage® technology which went on to be used in the clean-up following the Fukushima Daiichi accident in Japan.

Closer to home, Createc used its intellectual property in computer vision to build a business opportunity and set up spin-out company, Sportlight. Earlier this year, it launched a second spin-out from its robotics expertise creating Createc Robotics.

Looking ahead, as society and industry move out of a Covid-19 lockdown, Matt sees robotics playing an ever more important role – but warns those who think it will be an overnight change, to be more patient. “Society has always overestimated what technological development will take place over a two to five-year period. But it has always underestimated what development will take place over 20 years,” said Matt.

“Technological development is an accumulation of small goals which build on top of each other. It creeps forward so that over a 20-year period people then look back and are amazed at how much the world has changed. In 20 years’ time we are going to have a lot more robots, and we will have improved collaboration between human and machine. In some areas that might involve helping to remove people from having to carry out tasks in hazardous environments. In other areas it might be giving people more senses and more capabilities.”

Createc applies its thinking and technologies to any problem to find a solution, and takes a flexible approach when doing so. This means that it can adapt for a range of industries and a range of situations. “We look at the way we can do something, not where we can do it,” said Matt. It’s an approach which has seen its solutions applied in a range of industries and settings, including nuclear and defence, rail and security. Among future growth areas for Createc are heavy engineering, major industrial and general construction.

Createc has received two Queen’s Awards in recent years, one for International Trade and one for Innovation, recognising the company’s success in developing technology. The company is also proud to have won awards for innovation from The Institution for Engineering and Technology (IET), The International Atomic Energy Agency (IAEA) and Nuclear Decommissioning Authority (NDA).

Createc’s strategy as it moves beyond its 10-year anniversary is to concentrate on research and development to launch a series of further spin-out companies. Two things Matt is keen to influence in the wider economy to help support the company’s ambitions are funding and leadership. “We need to make sure that the UK is more start-up friendly. And we need more entrepreneurs who want to come and run these businesses,” said Matt. “To me an entrepreneur takes complete ownership and picks their way forward and proceeds confidently in the face of doubt.”

“We have had a sustained growth rate of 40 per cent, and we are focused on continuing to grow at this rate. In the first ten years we have grown from a company with three people turning over £180,000 to 30 people turning over £3.5m. To sustain that level of growth by the end of the next ten years we would have 300 people turning over more than £60m.”

Matt has a clear vision of how the company will keep driving forward, and his motivation and appetite to lead the company to further success is clear. “My motivation comes from bringing something completely new to life which results in the world being a better place,” he said. “Seeing all the pieces come together and creating this thing which creates an economic benefit and also has a positive impact on the world is really satisfying.”