Messier-Dowty's move to model based definition

Citation

(2006), "Messier-Dowty's move to model based definition", Aircraft Engineering and Aerospace Technology, Vol. 78 No. 6. https://doi.org/10.1108/aeat.2006.12778fab.001

Messier-Dowty's move to model based definition

Keywords: Aircraft, Aircraft components

When Messier-Dowty was selected to produce the nose and main landing gear for the new Boeing 787 Dreamliner, the UK aerospace manufacturer initiated the use of model-based definition throughout the design, manufacturing engineering, production and inspection processes at its operations in Gloucester, UK, and Bidos, France. It is the first major program for which Messier-Dowty has used model based definition.

Three-dimensional CAD models had been used in the company's design, and manufacturing engineering departments for more than a decade to develop and validate design definition, functionality, finite element analysis and manufacturing processes. However, the programming of co- ordinate measuring machines (CMMs) to inspect components after machining had been carried out traditionally using 2D toleranced drawings derived from 3D data. This was due to there being no geometric dimensioning and tolerancing (GD&T) information attached to the electronic model.

Now, using Dassault Systems' Catia V5, 3D CAD models for the Dreamliner landing gear components are annotated using a Catia workbench named “FT&A” (functional tolerancing and annotation). The FT&A workbench provides and helps control the application of GD&T – definitions that are attached to the 3D model, and enables the electronic 3D model to contain the comprehensive product definition.

Downstream, specific manufacturing engineering, production and inspection applications are being implemented to realise the significant benefits available with model-based definition. A sister product to CATIA in the Dassault portfolio, Smarteam (RDM), manages all the product data throughout the entire process.

CMM manufacturer and software developer, LK, recently acquired by Metris, was chosen by Messier-Dowty as its metrology partner to underpin inspection of the Boeing 787 landing gear components throughout the manufacturing process. Two Metris LK Evolution CMMs with a 2m bridge and 4m X-axis were installed during May 2006, the order having been placed in January. The turnkey contract involves training of the Messier-Dowty inspection team, which started during April, as part of a full, on-going service and support package.

Principal Engineer Pete Willis, responsible for the development of model-based definition inspection at Messier-Dowty's Gloucester facility, advised that he and his overseas counterparts have standardised on Delmia Inspect – also Dassault software – to create DMIS standard measuring programs off-line for the CMMs. Delmia will output DMIS programmes that interface with LK CAMIO CMM software to allow users seamless use of this programming, simulation and verification solution.

Pete says that the system aims to satisfy three key issues related to model- based definition inspection. The first is to avoid any translation of CAD authority data to preserve the integrity of the design definition. Secondly, the solution reads the FT&A attached to the model and thus minimises operator input during the development of CMM programs, improving the accuracy and integrity of the inspection process.

Lastly, the system provides a rules- based solution to standardise the methodology of the inspection process. The predefined rules relate the feature type, tolerance and feature size to determine the appropriate probing strategy for the specific feature, leading to a high degree of measuring consistency.

Analogue scanning has been included on the new CMMs to collect large amounts of data efficiently on the manufactured components in fast cycle times, leading to a greater understanding of the characteristics of the production processes.

“We did not want to just buy another CMM,” stated Pete. “Our business is making landing gear and we were looking for a metrology solution provider that would work with us to further improve our products.”

“We did not want to just buy another CMM,” stated Pete. “Our business is making landing gear and we were looking for a metrology solution provider that would work with us to further improve our products.”

“After an extensive evaluation of the leading suppliers, we opted for LK, now Metris, as it demonstrated a commitment to tailoring a metrology package that dovetailed with our requirements.”

In this connection, he cited various aspects of the project. First, Metris extended its LK Evolution machine range to accommodate Messier-Dowty's requirements for a large bridge CMM. Both new CMMs, each with a large measuring volume, will enable Messier- Dowty to load a major structural component, such as a machined titanium truck beam or any one of the smaller components, at one end of the machine while inspection is in progress at the other. Alternatively, the 4m X-axis will allow an entire Airbus 340 main fitting, for example, to be inspected without the need for repositioning. Similarly, larger machined landing gear forgings could be inspected with ease.

Another Metris innovation, the development and introduction of which has been supported and accelerated by Messier-Dowty, is automatic sensor management. Instead of spending between 10 and 25min calibrating a series of probes before each new job, an automated system has been developed which will calibrate all the probe configurations held within the racks during a single weekly routine, which will then be used throughout the following week. The unattended calibration process is initiated as an “out of hours” timed event, typically during Sunday afternoon so that the machines are ready and operational at the start of the Monday shift.

A 20-station Renishaw rack is being fitted to each machine and Pete is in the process of rationalising the probe head/ stylus combinations so that a maximum number of inspection functions can be performed by a core suite of probes. One of the capabilities being built into the two Metris LK CMMs is remote system monitoring. Apart from giving a management overview of machine usage, this will also hold real-time data on the remaining service life of all probes, ensuring that one nearing the end of its useful life is not deployed for a new measuring routine.

Other Metris developments, already in the pipeline but speeded by Messier- Dowty's leading-edge requirements, included the interfacing of Delmia Inspect with LK CAMIO software. Pete also recognises that Metris software is in the vanguard of integrating other third party software, which may be of use to Messier-Dowty, such as the products from statistical analysis and reporting software company, Q-DAS.

Last year, LK signed a licensing agreement with Metronor to integrate to the AIMS protocol, developed in conjunction with Boeing to enable open-architecture, worldwide sharing of CAD geometry, inspection plans and measurement results without inaccuracies or data loss, even when dissimilar hardware and software platforms are being used.

LK's former technology partner and new owner, Metris, is able to provide total solutions for 3D digitisation, inspection and reverse engineering, should these be required in the future by Messier-Dowty.

Pete concluded, “Migration from 2D drawings to a 3D model based definition manufacturing and inspection environment is the most significant and challenging development that I have seen during my 30-year career in aerospace engineering.”

We are now focussed on developing our processes to exploit the model based definition environment and are looking forward to reaping the productivity benefits and exceeding our customers expectations for quality, performance and cost.

Messier-Dowty, a SAFRAN group company, has entered the detailed design phase of the Boeing 787 landing gears. The design activity is concentrated at the company's Seattle office and staffed with engineers from Seattle and from Messier-Dowty sites in Toronto, Canada, as well as from the UK and France (Plate 1).

Plate 1 Messier-Dowty Gloucester personnel in front of the landing gear, left to right: Phil Spiers, Manufacturing Development Manager; Nick MacFarlaine, Procurement Team Leader; Peter Willis, Principal Engineer – Metrology. Metris personnel behind the landing gear, left to right: Alan Instone, UK Sales Engineer; Paul Davies, UK Sales Manager

The first sets of 787 landing gears will be used for Boeing's aircraft systems rig, due for delivery in late 2006. Subsequent sets will be used for development testing in-house at Messier-Dowty, undergoing a complete program of testing through to certification, followed by gears for flight-testing at Boeing. The first units to be fitted to production aircraft are scheduled for delivery in 2007.

Production for the 787 will take place at Messier-Dowty's various manufacturing facilities around the world.

Details available from: Metris UK Ltd, Tel: +44 1332 811349, Fax: +44 1332 850149, E-mail: sales@metris.com, web site: www.metris.com

Europe: Tel:+32 16 74 01 14, Fax: +32 16 74 01 02