Dimensional inspection of large objects

Aircraft Engineering and Aerospace Technology

ISSN: 0002-2667

Article publication date: 1 August 2000




(2000), "Dimensional inspection of large objects", Aircraft Engineering and Aerospace Technology, Vol. 72 No. 4. https://doi.org/10.1108/aeat.2000.12772dab.004



Emerald Group Publishing Limited

Copyright © 2000, MCB UP Limited

Dimensional inspection of large objects

Dimensional inspection of large objects

Keywords: Alignment International, Measurement

Alignment International has launched an additional measurement service providing dimensional inspection of large objects on site. The service is based around the new Metronor Solo portable CMM camera system which is used to directly measure and digitise surfaces and features in x, y and z co-ordinates to an accuracy of less than 0.05mm. The measurements can be compared directly to CAD drawings showing deviations from the computer model in real time or can be used to generate re-engineering drawings for repair, assembly and machining set-up.

Metronor have built their reputation primarily in aerospace and automotive industries particularly for "body in white" process methodology with customers including Volvo, Daimler Chrysler, General Motors and Boeing. Over 70 Metronor Dual Camera Systems have been sold in four continents.

Included amongst many high profile projects with which Metronor systems have been closely involved are the International Space Station Programme, the Joint Strike Fighter project (JSF), and the record breaking launches of the Chrysler Neon and VW Golf.

The new SOLO system is a co-ordinate measuring machine (CMM) that handles volumes up to 15m, exhibits a "2-sigma sphere test accuracy of less than 0.05mm, a 3D length accuracy (bias) of 0.1".

It reportedly can handle large volumes because of its electro-optical working principle. A single high-resolution charge-coupled device (CCD) sensor, or camera, works with Metronor's patented smart-LED Light Pen to make direct feature measurements throughout the camera's field of view - just like a traditional CMM. Designed to provide easy reach and access in small as well as large volumes, SOLO is novel in having no moving mechanical parts and claims excellent long-term stability and reliability. So portable is it that it can even be checked as aircraft baggage.

Dr Barry Bassnett, MD of Alignment International, states:

... in order to remain the leader in our field with regard to product quality, cost-efficiency and customer service, we are constantly looking for improvements - both in the tools we use and in the procedures we follow. When we became aware of the SOLO, we immediately recognised the very good fit with our requirements and the opportunity for more efficient and flexible measurement procedures. SOLO has primarily three characteristics that bring us savings:

  1. 1.

    It can handle the largest of our customer applications. Components from an engine block to a whole aircraft or pipe-work network in a single set-up, saving time and improving accuracy. In the past we have used articulated arms, which are very good systems but cannot effectively handle the volumes that we need to measure. A major benefit is that it allows us to measure to features that we cannot easily pick up with laser trackers or theodolites systems. Of course, taking the measurement machine to the task is, in most cases, a far more cost-effective and relevant option.

  2. 2.

    With the Metronor CAD software module, SOLO enables us to compare the actual object with the latest-revision CAD design in real time, and provides immediate graphical results to the operator and engineers. We avoid the need for inspection blueprints and the problems associated with misinterpretations and outdated revision levels.

  3. 3.

    The ability to analyse geometric functions on site, hole and bore sizing and pitching, flatness, roll parallelism or indeed any entity and to generate CAD models of virtually any component give us and our customers a tool with immediate impact and huge commercial benefits.

  4. 4.

    SOLO is portable and quick and easy to set up. We can use it where it is needed - at our own facilities or at our suppliers' sites. The inherent reliability and speed of set-up mean we can arrive and start measuring within minutes. Our first SOLO has been almost constantly "on the road" since delivery and we will undoubtedly be expanding our fleet in the near future.

The addition of the Metronor system adds to Alignment International's already extensive measurement capabilities that include alignment of rotating machinery and geometrical inspection services, 24 hours a day, world-wide.

Details available from: Dr Barry Bassnett. Tel: +44 1226 294900; Fax: +44 1226 291195; E-mail: laserbaz@alignment.co.uk

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