The Traffic
Cop - Root Cause Analysis
Such a large drop in tool utilization on the 5xStep
tool group leads the Traffic Cop to look more closely at
the tool states in this group. The chart below shows SEMI
E-10 states, averaged across the six 5x Steppers. The red
unscheduled downtime bar is clearly larger for the night
shift of May 23rd (when the problem with WIP turns and
moves began).
A closer look at the states of each tool during the
night shift on May 23rd is shown below. The Traffic Cop
observes that three of the six tools in the group had NO
productive time at all during the shift. A fourth tool in
the group spent more than 15 of its time idle - despite
the overall WIP building in the area.
The reduced capacity of the 5xStep tool group clearly
contributes to the overall problems with inventory age and
WIP turns in the factory. The Traffic Cop takes the
analysis one step further, by looking at the impact on
cycle time. (Continue to the next
page.)
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