In this paper a closed loop supply chain for a reusable, deteriorating tool is presented. The tool is used in a manufacturing process on an item in a linear supply chain. A model is created for the linear item supply chain and the tools closed loop supply chain to analyse the interactions between them and various input parameters so that output responses of the system can be modelled. Three approaches are taken to model the system, a brute force factorial design, a modified version of a Latin hypercube space filling design, and a fast flexible space filling design. It is found that all three methods can describe responses that require only a few inputs well but cannot accurately predict more complex responses without all the relevant factors. Space filling designs should be used if more factors are needed as they minimise the total amount of simulations needed to produce an accurate model.