Integrated Dimensional Variation Management in the Digital Factory

This paper describes how dimensional variation management could be integrated throughout design, manufacture and verification, to improve quality while reducing cycle times and manufacturing cost in the Digital Factory environment. Initially variation analysis is used to optimize tolerances during product and tooling design and also results in the creation of a simplified representation of product key characteristics. This simplified representation can then be used to carry out measurability analysis and process simulation. The link established between the variation analysis model and measurement processes can subsequently be used throughout the production process to automatically update the variation analysis model in real time with measurement data. This ‘live’ simulation of variation during manufacture will allow early detection of quality issues and facilitate autonomous measurement assisted processes such as predictive shimming. A study is described showing how these principles can be demonstrated using commercially available software combined with a number of prototype applications operating as discrete modules. The commercially available modules include Catia/Delmia for product and process design, 3DCS for variation analysis and Spatial Analyzer for measurement simulation. Prototype modules are used to carry out measurability analysis and instrument selection. Realizing the full potential of Metrology in the Digital Factory will require that these modules are integrated and software architecture to facilitate this is described. Crucially this integration must facilitate the use of realtime metrology data describing the emerging assembly to update the digital model.</p

Large Scale Metrology In Aerospace Assembly

The paper presents a review of the principles and state of the art in instrumentation used to make large scale measurements within aerospace assembly. The ability to measure large artefacts accurately is a key enabling technology to improve quality and facilitate automation. Particular emphasis is placed on issues of uncertainty with the importance of acceptance criteria explained and verification standards compared and discussed. The fundamental technologies deployed are explained including laser trackers, indoor GPS and photogrammetry. Commercially available systems are compared in terms of uncertainty, range and deployment related issues

Design for measurement assisted determinate assembly (MADA) of large composite structures

This paper describes how Measurement Assisted Determinate Assembly (MADA) can facilitate the lean production of aerospace structures, provided that the structure is designed for MADA. A novel wingbox design and production process is used to illustrate this. The aerospace industry has not benefited from the significant reductions in production cost and cycle time that can result from greater assembly efficiency, part-to-part interchangeability and the use of flexible automation. This is largely due to the very high accuracies required across large scale assemblies. The use of metrology can reduce process steps, reduce the reliance on costly hard tooling, reduce the requirement for manually intensive and time consuming re-working at late stages of assembly, and allow low cost flexible automation to place tools to the required accuracies. The generic MADA process is presented together with guidelines for the design of structures to enable MADA

Concepts for and Analysis of a High accuracy and High Capacity (HAHC) Aerospace Robot

Case study work carried out within the aerospace sector has highlighted the requirement for highly accurate and high capacity robots in aerospace assembly; literature supports this observation. This paper presents the generic capabilities of such a system. These include the ability to rapidly locate itself within a large measurement volume using supplementary laser metrology systems, to carry out detailed inspection beyond the line of sight, and to accurately locate parts, drill holes and fettle interfaces. Concepts are presented for a standardized robot which would provide a flexible automation system able to carry out a full range of operations required in the assembly of large aerospace structures. Two possible solutions are detailed, one based on error mapping and one based on the physical isolation of encoders from structural loading using an exoskeleton approach. </jats:p

The Metrology Enhanced Tooling for Aerospace (META) Framework

Aerospace manufacturers typically use monolithic steel fixtures to control the form of assemblies, this tooling is very expensive, has long lead times and has little ability to accommodate product variation and design changes. Since the tool setting and recertification process is manual and time consuming, monolithic structures are required in order to maintain the tooling tolerances for multiple years without recertification. This paper introduces the Metrology Enhanced Tooling for Aerospace (META) Framework which interfaces multiple metrology technologies with the tooling, components, workers and automation. This will allow rapid or even real-time fixture re-certification with improved product verification leading to a reduced risk of product non-conformance and increased fixture utilization while facilitating flexible fixtures.</p