A decision model for kitting and line stocking with variable operator walking distances

Purpose - The purpose of this paper is to propose a decision model to choose between kitting and line stocking at the level of single parts, while taking into account the variable operator walking distances. Different ways of feeding assembly lines, such as kitting and line stocking not only have an impact on in-plant logistics flows but also determine the amount of stock that is available at the line. This, in turn, has an impact on operator walking distances during assembly. Design/methodology/approach - A mixed integer linear programming model is developed for the assignment of parts to one of both methods, and to be able to extensively test the model, an algorithm is created for the construction of representative datasets. Findings - Parts are often kitted because of a space constraint at the line, but even without a space constraint, the shorter walking distances might give preference to kitting. An analysis is presented that demonstrates how specific part characteristics influence the chances of a part being kitted. Research limitations/implications - Our research model can be extended to include, e.g., the study of alternative in-plant logistic designs and the outsourcing of kitting to a third-party logistics provider (3PL) or to the suppliers. Practical implications - The objective assignment model and the insights obtained from it are valuable for logistics and production engineers that otherwise have to rely solely on intuition. In situations with thousands of components, intuition mostly falls far short. Originality/value - First, existing models do not consider variable walking distances, which are shown to have a crucial impact on the decision. Second, the data instances created allow for a systematic comparison of future research in the field.