Figure 6.5 compares process flows b

Figure 6.5 compares process flows before and after creation of GT cells. Figure 6.5(a) shows a shop floor where machines are grouped according to function: lathing, milling, drilling, grinding, and assembly. After lathing, a part is moved to one of the milling machines, whereit waits in line until it has a higher priority than any other job competing for the machine’s capacity. When the milling operation on the part has been finished, the part is moved to a drilling machine, and so on. The queues can be long, creating significant time delays. Flows of materials are jumbled because the parts being processed in any one area of the shop have so many different routings.By contrast, the manager of the shop shown in Figure 6.5(b) identified three product families that account for a majority of the firm’s production. One family always requires two lathing operations followed by one operation at the milling machines. The second family always requires a milling operation followed by a grinding operation. The third family requires the use of a lathe, a milling machine, and a drill press. For simplicity, only the flows of parts assigned to these three families are shown. The remaining parts are produced at machines outside the cells and still have jumbled routings. Some equipment might have to be duplicated, as when a machine is required for one or more cells and for operations outside the cells. However, by creating three GT cells, the manager has definitely created more line flows and simplified routings.