Lot-sizing and flow production in an MRP-environment

In the paper methods are developed to analyze a production process for professional equipment with advanced electronic and mechanical features. The starting point of the analysis is to find ways for production control and production organization which conserve and even strengthen the advantages of the MRP-system used: shorter and better controlled throughput times, but also mend the disadvantages to a large extent: high order release costs, unnecessary material handling and high costs both in time and money of data processing. The authors used the well-known built-in concept of phantoms to release material for a number of production stages without explicitly generating a shop order for each stage. Together with the release of the material a shop order is released for the first stage of a set of production stages. Shop floor control ensures that the next stages of production are completed within the projected time until another production stage is entered for which a shop order is released. The result of this approach is more flexibility in terms of shop floor control: a number of stages can be scheduled in a more sophisticated way than just by backward scheduling. This leads to reduced throughput times. Additionally, inexpensive material is stored in bulk on the floor and replenished periodically, thus reducing the number of levels and the complexity of the Bill Of Materials. This resulted in reduced costs and response times of the MRP system.