Scarborough-based Unison Ltd has recently installed a turn-key tube-bending package at British Airways’ Heathrow-based aircraft maintenance, repair and overhaul (MRO) facility. The order included a Faro ScanArm (
www.faro.com) that uses laser and tactile measurement techniques to obtain detailed and highly accurate 3-D representations of tubes, so that precise and rapid reverse-engineering can be undertaken.
Indeed, programs resulting from the measurements taken can be downloaded to British Airways’ new bending machines within minutes. The Unison solution — supplied to British Airways for fabricating tubular parts — is based on a CNC semi-manual bender and a fully CNC all-electric model.
British Airways maintains its fleet of aircraft in-house, as the loss of revenue resulting from the grounding of a modern aircraft can be astronomical. The company recently embarked on a major upgrade to its fleet of long-haul aircraft; this is set to include the addition of Boeing 787 Dreamliners and Airbus A380 super-jumbos over the next 10 years. The introduction of these latest-generation aircraft poses numerous challenges for the airline’s repair and maintenance personnel.
One of these challenges is the fabrication of replacement rigid hydraulic tubes, which on latest-generation aircraft are manufactured from specialist aerospace materials such as titanium alloy; moreover, thick-wall tubing is used to accommodate the high working pressures (for example, a 25mm-diameter hydraulic tube for an aileron actuator would typically have a wall thickness of 2.5 mm).
Following the decision to upgrade the tube fabrication capabilities of its repair and maintenance workshop, British Airways searched for a tube-bending machine manufacturer with proven expertise in the aerospace sector.
Unison (
www.unisonltd.com) was an obvious contender; the company’s all-electric tube bending technology is used by a number of leading aerospace manufacturers, including Boeing and Airbus, to produce parts for engines and airframes. In fact, Unison machines are already used to produce hydraulic fluid lines for both the 787 Dreamliner and the A380.
Turn-key MRO package
For the British Airways application, Unison configured a complete measure/program/manufacture turn-key MRO package for tubular components ranging in diameter from a few millimetres up to 40mm and in materials that include stainless steel and titanium alloy.
For the more-demanding applications, a single-stack 40mm machine from Unison’s Breeze range of all-electric tube benders was selected; also specified for this was Unison’s laser-controlled spring-back measurement and correction system.
For bending intricate stainless-steel tube parts with smaller diameters, Unison specified an EvBend 1000 machine; this CNC manually powered machine is ideally suited to precision low-volume work.
If a suitable CAD file for a tubular part is available, tube fabrication data can be extracted and downloaded directly to the appropriate bending machine.
However, a more likely scenario is that — at least in the first instance — there will be no supporting design data for a tube that needs replacing. In this instance, after removing the worn or damaged part from the aircraft, maintenance personnel will obtain the tube’s physical measurements using the Faro ScanArm and then process the information to create a suitable bending program.
Unison’s managing director, Alan Pickering, says: “This turn-key solution required the exacting integration of hardware and software to create a seamless production environment for efficient on-demand manufacture, which is why we included Faro’s ScanArm and software as part of this turn-key package.
“Hand-held laser scanners provide a quick and effective way to inspect and reverse-engineer complex parts and surfaces. Moreover, soft, deformable and complex shapes can be easily inspected — without the equipment ever coming into contact with the measured part.”