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Development of a Bespoke Laser Site Welding System

Development of a Bespoke Laser Site Welding System

Following on from the success of a series of lab-based projects to develop a new laser welding procedure and prove it fit for purpose, TWI has supported TechnipFMC to develop new product capability, by designing, manufacturing and then acceptance testing a laser site welding system for a complex bespoke application on pipe.

Background

TechnipFMC UK approached TWI to help it assess the feasibility of carrying out laser welding on site, to make a series of welds, in otherwise inaccessible locations, on one of its new product developments.

Initial laboratory work

Initially, TechnipFMC’s site welding requirements were mocked up by TWI on a lab scale. Welding trials were carried out using standard equipment, on representative coupons, in an environment reflecting that which would subsequently be imposed on site.

A first round of trials helped to develop process understanding, identifying suitable laser beam equipment to use and the range of situations over which that equipment could be applied successfully, as well as determining the welding results that could be achieved.
A second round of trials then focused on determining the tolerances of a chosen welding procedure to changes in its essential variables, with the emphasis on maximising these tolerances for robust site work, as well as confirming the fitness-for-purpose of the welds made.

Installation of the laser (right) and its chiller (left) on site - after a 500 miles plus road trip.

TWI-manufactured system safety control unit in site use.

Work culminating in a site demonstration

Following these lab trials, a TWI project team was assembled with expertise in laser engineering, electrical system engineering and component design. This team developed a concept for a Class 1 laser site welding system, in discussion with TechnipFMC and another of its subcontractors. The team’s combined experience, backed up by impartial third-party laser safety oversight, ensured that the concept was in line with relevant ISO and IEC laser and machine safety standards.

After a concept review, including a comprehensive documented failure modes and effects analysis (FMEA), TWI produced a full set of engineering and electrical drawings for the bespoke mechanical and control components of the system, compatible with the other commercially available laser equipment needed to complete the system.
With client approval of these drawings, the bespoke components were then manufactured by TWI’s machine shop and electrical services group, who also went on to support TWI’s lasers team with their integration in to the overall system, ready for lab testing.
Lab acceptance testing of the system was then successfully carried out, as witnessed and signed off by the client and an independent third-party laser safety consultant. The system was tested on mock pipes, at a scale representative of its final application. This testing confirmed the positive transfer of the previous lab conditions, meeting client weld quality and performance requirements. This testing also usefully highlighted a small number of remaining snagging points for smooth system operation, which were then easily rectified by TWI before final system completion.

With the acceptance phase of the project fully completed, the different elements of the system were then road-transported to TechnipFMC’s site on the Cromarty Firth in Scotland, for the follow-up site integration test.

Whilst the nature of the site work carried out remains confidential, this article can share the snapshots shown of that work, and report that the integration, and its results, were successful, fully meeting client expectations.

Martin Chalmers, TechnipFMC’s lead on this project, summarised the overall project: “This scope of work was an effective collaboration between TechnipFMC and TWI as part of a new product development for TechnipFMC. We approached TWI with a conceptual solution to a challenging welding problem where we believed laser welding could offer the best solution. TWI took the idea through proof of concept, detailed design, fabrication and ultimately proving the approach fit for purpose on site at our onshore pipeline fabrication facility in Scotland. Working with TWI’s experience and expertise in specific fields of welding technology allowed us to develop a practical solution to an otherwise complex issue. We look forward to working together again on upcoming technology developments.”

Pipe on site, on which the laser welding work was carried out.

Chris Allen Consultant

Dr Chris Allen is a Consultant in the Laser and Sheet Processes Section at TWI Ltd, and has over twenty years' experience as a welding engineer. He has an MA from Cambridge in Materials, and a PhD from Oxford, carried out in conjunction with Alcan. Following a short stint in academia, Chris has been in a technical project role since 2000, firstly at Corus, and then at TWI. Chris has developed, managed and delivered R&D projects, principally in laser processing, for clients in the aerospace, road transport, powergen, defence and shipbuilding industries, with clients including Rolls-Royce, GKN Aerospace, Saab Aerospace, Leonardo MW, ESA, Honda, Honeywell, JCB, Nippon Sharyo, UKAEA, Lockheed Martin, MBDA, Technip, Saipem, and the MoD/DSTL, as well as the European Commission and InnovateUK.

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