Evaluating alternative production cycles using the extended fuzzy AHP method

Production technicians can generally choose any one of a number of alternatives for producing a component. The combination of the possible alternatives leads, in turn, to a large number of production cycles. The production technician now has to decide which of the many production cycles available are best suited to yield the desired processing results, in line with predefined targets. These targets may include low production costs, an optimum degree of capacity utilisation, minimising environmental pollution, or such like. The problem arising, i.e. which alternative to choose, can be tackled with the aid of the analytical hierarchical process (AHP), which stems from multi-criteria analysis. Due to the integration of product and process design the decision should be made at any early stage of product design. This makes a decision process more difficult. Therefore the input data loses precision, and this must be treated accordingly. The method presented here of evaluating different production cycle alternatives takes due account of this by adding the mathematics of fuzzy logic to the classical AHP. Any production cycle evaluated in this manner yields a fuzzy set. The outcome of the analysis can finally be defuzzified by forming the surface centre of gravity of any fuzzy set, and the alternative production cycles investigated can be ranked in order in terms of the main objective set. (C) 1997 Elsevier Science B.V.