Product Data Technology
October 1997
prepared by PDTAG-AM
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Product Data Technology Advisory Group ESPRIT 9049 |
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Policy Recommendations for Developments in Product Data Technology October 1997 prepared by PDTAG-AM |
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Aerospace makes extensive use of IGES and SET to exchange data today, expending valuable manpower to ensure an adequate degree of translation.
Through the European Association of Aerospace Industries (AECMA), European aerospace companies have agreed their overall requirements for product data exchange, and have assessed STEP AP203 against the existing AECMA standard. It appears to be viable to replace the industry-specific standard with STEP in future, and the industry is attempting to establish a pilot project to demonstrate this. Strong interest is now being shown in the exchange of wiring harness data using AP212, and the industry submitted its existing data definitions to the development process to assist in establishing the requirements. There is also a need for guidelines to assist companies in their implementation plans.
Individual aerospace companies are also collaborating in a number of ESPRIT R&T projects related to PDT. These cover configuration management, a range of specific digital mockup functions and the downstream process planning, manufacturing and inspection integrated through the AIT integration platform to access distributed product databases using STEP technology.
The European Space Agency, ESA, has created its own AP on Spacecraft Thermal Analysis, independent of ISO, which provides some assurance of the validity of the existing STEP methodology. No attempt has yet been made to integrate these results with the overall standard.
The major obstacle to further deployment of STEP and other exchange technologies is currently the poor quality of results produced by commercial translators, although this situation is gradually improving through the efforts of industry fora such as PDES Inc. and ProSTEP. However, detailed analysis of the problems has revealed that the source of the problem is often poor quality geometry, with discrepancies at the level of system modelling accuracy – analogous to the tangency problems that often plagued early CAD/CAM systems.
The neutral file approach is in competition with the use of common systems to simplify data exchange, although the effectiveness of the latter approach is often impeded by different operational procedures and installation configurations. The current trend is still for the prime contractor to demand data in native form from its contractors.
In contrast to the neutral data exchange approach, Airbus Industry has required partner companies to adopt a common CAE system to simplify product data transfer in future products, but this is not likely to extend to their supplier base, so there is a continuing need for standards such as STEP to offer improved translator capability.
In the US, McDonnell-Douglas has developed the world's first production implementation of STEP, for the exchange of product structure information between Long Beach and St Louis on the C-17 military freighter programme. This is confidently predicted to drive down the costs of maintaining an audit trail for the product configuration – traditionally a time-consuming activity, especially where there are two incompatible configuration management systems involved. Boeing have agreed to use STEP for the exchange of geometry with Rolls-Royce, for Digital Pre-Assembly of engine installations.
Again in contrast, McDonnell-Douglas has achieved conspicuous success on the F-18E/F fighter programme, using a common system between the partner companies.
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