Process system specialist, George Koch Sons Europe has completed a major penetrant flaw detection facility for Airbus UK as part of the aerospace manufacturer’s move from chromic to tartaric sulphuric acid anodising.
The installation in Chester is now understood to be one of the largest such facilities in the world and operates alongside a purpose-designed water treatment plant, also installed by George Koch. The multi-stage, self-contained installation is now a key element in the manufacture of Airbus wings and associated components.
“The move from chromic acid-based chemical solutions to tartaric sulphuric acid meant that the original visual inspection method for crack detection could no longer be utilised,” comments George Koch’s sales manager, Steve Moseley. “The use of fluorescent penetrant dye inspection was considered the most appropriate alternative – the procedure being centred on the application of fluorescent penetrant spray and developer powder, followed by a detailed UV inspection.”
To create a focus for the facility and to accommodate space restrictions at the site, George Koch’s solution was to build a single, self-contained PFD inspection chamber. This would not only house the 11 separate stages that form part of the process but would also enable ambient light to be shut out to create the ideal environment for UV inspection at the end of the line. Operations within the enclosure include spray, rinse and drying before the application of the developing powder to aid visibility during the manual UV inspection.
A highly-innovative handling system is central to the design of the new system. Based on a floor-mounted gantry which moves laterally through the enclosure, station by station, relevant process nozzles and applications are presented to each component as it proceeds.
“The final stage sees the UV lighting for the penetrant dye being assessed by specialist operators – a procedure which is optimised by the enclosed configuration. “Any potential defects are revealed as fluorescent indications,” notes Moseley.
He also draws further attention to a number of other key design features that have addressed particular performance objectives specified by Airbus: “The oven element of the PFD booth, for example, has been designed to fulfil a dual role because it raises the relevant air temperature to some 70°C and also performs the dry-off function, as required. Additionally, the chamber features other elements that optimise the operation including a raised grid floor with a stainless-steel under-floor, and insulated supply and return duct work to enable various air flow profiles and temperature settings to be achieved.”
He points out that the control system can also be set to function in several different modes, enabling the PFD processes to be optimised for each operation. Additionally, George Koch has installed a wastewater treatment plant alongside the chamber which is dedicated to the PFD operation.
“This removes the fluorescent dye from the wastewater enabling it to be re-used, with waste then separated for appropriate disposal,” adds Moseley. “The project is an excellent demonstration of both our belief in working closely with each customer to respond to exact needs, and also of the range of processing and handling systems which we can incorporate into each project solution.”
He points out that the project works in conjunction with a previous George Koch installation at the plant, which enabled the move from chromic to tartaric sulphuric acid to be achieved.
“The bringing together of so many operational stages into a single, space-efficient unit, with built-in performance capability and versatility, has addressed the key objectives of this major project at Airbus. The result is an installation that is central to a wide range of component production at the site and, importantly, one which underpins the organisation’s commitment to moving away from chromic-based chemical usage,” he concludes.
