In this section we construct a flow analysis model that describes the processes, operations, machines, raw materials, and resources associated with production. Flow analysis is an abstraction of the production process that neglects the detail concerned with individual items of product, but considers the collection as a flow. Thus most of the parameters of the model relate to averages over time. Although certain responses of the system are lost with flow analysis, a number of questions important to system design and operation can still be addressed. The advantage of flow analysis is that it allows powerful analytical and algorithmic methods to be applied to problems without great expenditures in computational effort. The principal goal of the sections in this chapter is to describe how the important average quantities associated with production can be computed with the help of a model based on the process chart.

We use an example obtained from the Goldratt Institue and use it to describe how process flow analysis can be used. The section has allussions to the Theory of Constraints described in the popular book The Goal.