Evaluating shop floor input control using rapid modeling

A simple, spreadsheet-based rapid modeling approach to analysis of input control is developed. This approach uses relationships which allow decomposition of a job shop queuing network. Order release is based on a minimum release time interval, dictated by the bottleneck machine utilization. The objectives are to develop insights into how input control affects work flow and how rapid models can help in achieving this. The rapid model performs well and the order release mechanism is shown to be robust. Economic analysis based on throughput, inventory and lead time tradeoffs is provided. The value of input control is shown to be dependent on the cost structure. The impact on profitability is small, however, relative to the impact of operating at the optimal utilization level.