Evaluating the effects of inventory stockouts in the performance of production control systems

Studies on the performance of production control systems typically assume that materials are continuously available at stations, thereby neglecting the potential impact of inventory stockouts. Contrarily, this study assesses the performance behavior of two of the most known production control systems, namely POLCA (Paired-cell Overlapping Loops of Cards with Authorization) and WLC (Workload Control) under inventory stockouts, in an assembly-to-order system. For a better understanding of such behavior, Load-Based POLCA (LB-POLCA), i.e. a variant of the POLCA system that takes into account the workload of jobs, is also considered in the study. The study is carried out using discrete event simulation. Results show that stockouts induce loss of system performance, as expected, but the relative performance of the production control systems tested does not change in relation to the situation of continuous availability of materials. Moreover, delivery performance is best using WLC followed first by LB-POLCA and after by POLCA.