A model for planning and economic comparison of manual and automated kitting systems

Parts kitting is a frequently adopted method to feed parts from a warehouse to an assembly line. While kitting allows minimisation of space occupation and Work In Process holding cost at the workstations, also simplifying materials flow and supporting manual assembly, it is penalised by high workforce cost for manual kits preparation. For this reason, automated kitting systems have been also proposed although their practical application is somewhat limited owing to the relevant capital investment and scarce performances of robotised kitting systems. Moreover, economic models allowing a quantitative comparison of manual and automated kitting systems are not yet available in the literature. As a contribution to fill this gap, in this paper a cost model useful to compare manual and automation-assisted parts retrieval and kitting systems is presented. The model can be used as a decision-making tool when planning and justifying kitting systems. The model includes capital investment, workforce, space occupation and quality costs. A case study as an application example is also included to demonstrate the model capabilities. Results show that automation-assisted kitting systems can be competitive in comparison to manual kitting and that break-even conditions can be also identified by the proposed method.