Cell Design for Transforming the Job Shop Production Process to Lean

Research Background

The subject of material flow optimisation comes under production flow management or logistics management, which includes all aspects of every movement of raw materials, WIP and finished goods within a plant or warehouse (Lambert et al., 1998). Material flows are flows of physical goods, e.g. of transport units, vehicles or load units. Different from the continuous flow of bulk material moving on a conveyor is discrete material flow of single process units (Gudehus and Kotzab, 2009). In JIT production systems, the focus of attention for scheduling is deployed at the final assembly lines. The reason is because it is primarily important to complete units on schedule and produce at a constant level rate so that all operations supporting final assembly are synchronized (Hall, 1988).

An ideal target type of micro logistic chain is a synchronous material flow, where the structural and process issues are fully adapted to flexible reactions to any change in their environment. The material flow is balanced, smooth, without keeping a stock (with the exception of a minimal backup stock). Synchronous material flow design, then, can be defined as a systematic process that determines how to combine, integrate and synchronize material handling systems, manufacturing processes and information systems with the proper facilities layout. Such an operational strategy is also called Cellular Manufacturing that incorporates lean principles, but adds flexibility to the process. Most writers describe the U-shaped production line as the optimal type of cellular manufacturing used in JIT production systems. The U-line workstations can include tasks located on different parts of the production line (Gokcen et al., 2005).