ABSTRACT
When we first treated one-machine problems, we assumed that any setup times for a job were included in the processing time and hence constant with no impact on optimizing a measure. However, when changing from one job to another, the setup time may be dependent on the previous job. One example is the exchange of molds and plastic molding powders in injection molding. The time required to cool and heat the molds and to purge the machine of the previous powder is dependent on the difference in the properties of the powders and the size and complexity of the molds. Another example occurs in the assembly of printed circuit boards when there are either many or few common components to be placed on the circuit board. Different components need to be mounted on the insertion machines and this requires time.
