This paper describes the established process of cost model development and highlights opportunities for further improvement. Combinations of Systems Engineering tools were used within the modelling strategy in order to overcome the limitations of individual techniques. A functional modelling language was used to analyse, develop and integrate the cost model functions. The relationships between the manufacturing systems were modelled using Unified Modelling Language (UML). Furthermore, the benefits obtained by introducing changes to the cost model development process were evaluated by drawing comparisons between the two model development approaches.