The Product Rate Variation Problemand its Relevance in RealWorld Mixed-Model Assembly Lines

Production processes in a wide range of industries rely on modern mixed-model assemblysystems, which allow an efficient manufacture of various models of a commonbase product on the same assembly line. In order to facilitate a just-in-time supply ofmaterials, the literature proposes various sequencing problems under the term “levelscheduling”, which all aim at evenly smoothing the part consumption induced by theproduction sequence over time. Among these approaches, the popular Product RateVariation (PRV) problem is considered to be an appropriate approximate model, ifeither (i) all products require approximately the same number and mix of parts or (ii)part usages of all products are (almost completely) distinct. These statements are(iii) further specified by analytical findings, which prove the equivalence of productand material oriented level scheduling under certain conditions. These three prerequisitescommonly cited in the literature when justifying the practical relevance ofthe PRV are evaluated by means of simple computational experiments and are thendiscussed with regard to their relevance in practical settings. It is concluded thatthe PRV is in fact inappropriate for use in today’s real-world mixed-model assemblysystems....