The Shepherd: Consequences and Corrections

The arrival process variability to Operation 2700, combined with the tool dedication and equipment unavailability, results in a high variation in the number of moves per shift at Operation 2700 (as shown below).

Operation 2700 also displays a high variation in operation-level cycle times per visit. The average for each shift ranges from three hours up to 33 hours, across a two week period, as shown below. 

Corrective Actions

By analyzing inactives retrospectively, as in this example, the Shepherd can identify significant sources of cycle time (like the 33 hours per visit shown above), and suggest corrective measures. In the above example, actions to reduce tool dedication or to smooth the flow of arrivals into nitride dehydrate operations could be useful. More detailed analysis might reveal suggestions for improving the scheduling of preventive maintenance operations, to reduce the chance of lots arriving to find all eligible tools down. On an ongoing basis, managing inactives can also bring problems to light early, before large WIP bubbles have time to occur.

(Return to the main Cycle Time Management Styles page)