The Traffic Cop - Other Performance Measures

The Traffic Cop begins tracking down the problem that led to decreased WIP turns by looking at factory moves for the same time period. As shown in the figure below, the factory moves also decreased by about 15% between the day shift and the night shift on May 23rd. The moves stayed below goal for several days, before finally recovering on May 26th. 

The WIP remained essentially flat during the time period of interest. However, the inventory age began to grow during the night shift on May 23rd, and continued to grow until the 25th. The maximum inventory age reached was nearly double the minimum on May 23rd. Here inventory age is defined as the sum across all lots in the factory of the time that each lot has been at its current operation.

Clearly, then, the problem has to do with lots for some reason not being processed. The next step for the Traffic Cop is to identify which tool groups or areas are causing the problem. (Continue to the next page.)