A KBE genetic-causal cost modelling methodology for manufacturing cost contingency management

A KBE genetic-causal cost modelling methodology for manufacturing cost contingency management

Curran, R.
Gilmour, M.
McAlleean, C.
Kelly, P.

Aerospace Engineering

2009-12-31

The paper provides validated evidence of a robust methodology for the management of lean manufacturing cost contingency, with a particular focus on contingency regarding recurring work content. A truly concurrent engineering process is established by capturing a range of knowledge from the design, manufacturing and procurement functional areas, and analyzing it in a way that it can be automatically accessed with no specialist manufacturing knowledge, thus enabling the company to quickly estimate their designs based on the company’s lean manufacturing capability. A use-case study is presented which estimated the rolled-up assembly time for a thin-walled stiffened structure to be within ±7% of the manual estimating. A rolled-up accuracy of ± 10% was indicative in terms of total part and assembly cost, although it was evident that some of the individual cost deltas deviated more significantly, tending to cancel each other out in the roll-up. However, the key contribution of the paper is the implementation and validation of the use of the Genetic-Causal principle in developing a lean manufacture cost contingency methodology. Manufacturing cost models are established according to the principle of ‘causality’, which establishes which cost drivers should be used to generate the cost relations associated with the cost breakdown structure elements for various manufacturing processes. However, the ‘genetic’ principle is imposed through the hypothesis that the estimated costs of a new product will be similar to a company’s historical cost performance, relative to process selection, product definition and lean manufacturing capability. The latter use of the ‘genetic’ principle then presupposes that any new cost estimates generated are by nature not definitive and that rather one should be aiming to estimate the cost contingency. Consequently, the paper goes on to develop this hypothesis through a aircraft fuselage use-case to show how the lean concept idea of value added and non value added work content is consistent with this approach and indeed leads us to cost uncertainty and sensitivity analysis. Consequently, the paper advocates the formalization of an initially heuristic approach and so can be described inherently as a Knowledge Based Engineering (KBE) approach: capturing, structuring and formalizing manufacturing cost knowledge for application through knowledge bases and rules.

http://resolver.tudelft.nl/uuid:18655662-1970-46fa-9f6f-258eac9f0921

AIAA

1-56347-980-X

Proceedings of the 9th AIAA Aviation Technology, Integrations and Operations Conference, Hilton Head, Sept. 2009

Institutional Repository

conference paper

(c)2009 Curran, R.; Gilmour, M.; McAlleenan, C.; Kelly, P.