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This paper describes and demonstrates the use of an assembly centric design algorithm as an aid to achieving minimal hard tooling assembly concepts. The algorithm consists of a number of logically ordered design methodologies and also aids the identification of other enabling technologies. Included in the methodologies is an innovative systems analysis tool that enables the comparison of alternative assembly concepts, and the prediction and control of the total assembly error, at the outline stage of the design.

The Jigless Aerospace Manufacture (JAM) project has been set up to investigate the significant technological and economic issues to enable the minimisation of product specific tooling in the design and assembly of large aerostructures. As part of this on-going work, the use of error budgeting was explored to asses it suitability as a tool to enable the design of large aerostructures that would be easily assembled without recourse to expensive jigs and fixtures. This technique, which has been successfully used for the design of precision machines [1, 2], has the potential to allow the comparison of several concepts and configurations early in the design process and so help the selection process as well as highlighting areas where redesign should be considered at the detail design stage. This paper detail how such a technique can be used during design of aerostructures, in particular when these structures employ integrated location and reference features to help the assembly process.

This paper considers rhe use of structurally integrated location and reference features to simplify and to reduce the lead time and costs of assembling large aerospace structures. The location features are selected to fulfil a specific function based on restraint requirements and the necessary degree of precision to ensure that the Product Key Characteristics are achieved. Analysis of how to use structurally integrated location and reference features, indicates that their introduction will not be successful unless there is an integrated design team with a thorough understanding of the manufacturing processes and capabilities, the assembly processes, and the enabling technologies. The assembly of a single nose rib to a section of front spar is used as a typical assembly problem. Three alternative assembly processes are briefly described and used to illustrate the need for the industry to adopt an holistic approach to the design of aerostructure.

Jigless assembly is an approach towards reducing the cost and increasing the flexibility of tooling systems for aircraft manufacture through the minimisation of productspecific jigs, fixtures and tooling. A new, integrated methodology has been developed, which uses a number of building blocks and tools, to enable design for jigless assembly as a result of a logical, step-by-step process. This methodology, AIM-FOR-JAM, is currently being applied to redesign the Airbus A320 Fixed Leading Edge for jigless assembly, as part of the ‘Jigless Aerospace Manufacture’ (JAM) project.

The shear size and flexibility of the larger airframe parts makes it difficult to imagine assembly without extensive use of hard tooling. Yet, the world of aerospace manufacturing is changing. It is already possible to considerably reduce the amount of external, ‘hard tooling’, especially jigs, through innovative design and the applications of advanced technologies. Jigless Aerospace Manufacture, (JAM), is not a single, mysterious, as yet undiscovered technology. Rather it is a growing number of related and linked technologies. Many of these are already well established and considered ‘robust.’ This paper sets out to review and describe some of these enabling technologies and to explain their individual roles towards achieving JAM.