Laser tracking CMM technology

Aircraft Engineering and Aerospace Technology

ISSN: 0002-2667

Article publication date: 1 August 2000




(2000), "Laser tracking CMM technology", Aircraft Engineering and Aerospace Technology, Vol. 72 No. 4.



Emerald Group Publishing Limited

Copyright © 2000, MCB UP Limited

Laser tracking CMM technology

Laser tracking CMM technology

Keywords: Brookhouse Holdings, Laser sensors

Brookhouse Holdings, of Darwen, has invested in a 3D laser tracking CMM system to allow all divisions of the company to meet the very highest tolerances demanded by its customers, especially in the aerospace business. Although the investment was made primarily to comply with the rigorous specifications of the work Brookhouse is carrying out for the Eurofighter project, the state-of-the-art facility will also find application in other areas of the company's operations.

The new Leica LTD 500 tracking system (Plate 1) is described as a high accuracy, tracking laser interferometer, incorporating a high precision, absolute distance meter. Three-dimensional measurements are said to be taken at the rate of up to 1,000 per second and converted, encoded, stored and displayed on an integral PC. Hard copy reports can be generated and data can be exported to other Windows 95 compatible applications.

As with all interferometry based measuring equipment, measurements are made of changes in the distance between two reference points, in this case between a reflector and a measuring head. However, the built-in, infra-red absolute distance meter reportedly allows measurement to be recommenced almost immediately in the event of the beam being broken, which saves considerable time when measuring large complex objects, such as mould tools. In addition, by using an existing file of reference co-ordinates, sequential point measurement of, say, a tooling jig with fixed reflector targets can be achieved. A sophisticated software algorithm enables the operator to make a quick and approximate manual measurement of the first three points and the remaining points in the file are then automatically measured and their co-ordinates calculated.

Plate 1 The Leica LTD 500 laser tracking system being used to check the precise alignment of aerospace assembly jigs at the Brookhouse SPD Tool Company in Tameside

The new laser tracking system has a working volume of 70m x 35m x 12m and is totally portable, being supplied with its own trailer. It can be transported within Brookhouse operating sites in Darwen and Tameside and then located at the actual component to be measured rather than being situated in a central, air-conditioned measuring facility. Consequently, the system will be used to check the precise alignment of large assembly jigs at the Brookhouse SPD Tool Company in Tameside, to provide highly accurate measurement of 3D surfaces of complex geometry moulding tools and composite components using best fit technology at Brookhouse in Darwen and to carry out capability checks on CNC machines.

Brookhouse Holdings is one of the largest independent composites manufacturing and assembly organisation in the UK. It comprises five separate but complementary companies. Brookhouse Patterns Ltd specialises in the design and manufacture of tools in a wide variety of materials for composite components. Brookhouse Composites manufactures and repairs composite components and has particular expertise in the aerospace industry, with the capacity to handle large and complex assemblies, as well as minor details and interior trim panels and components.

Brookhouse Paxford, in Huntingdon, has long experience in providing tools and moulds for the automotive, aerospace, defence and simulation industries. Brookhouse Aerospace, at Stalybridge and Dukinfield, near Manchester, offers tool design and manufacture, detailed component manufacture for the aerospace industry, including flying parts, and heavy fabrication capability, as well as being a major supplier of ground support equipment and workshop, test and ground equipment. The Brookhouse (SPD) Tool Company provides a comprehensive design and manufacturing capability for the precision engineering of tools, jigs and fixtures.

Details available from: Brookhouse Holdings plc. Tel: +44 (0) 1254 706000.

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