3-Step Process with Rework
Consider the following three-step assembly operation with
quality
problems. All resources are staffed by one employee.
The first resource has a processing time of 7 minutes per
unit.
The second resource has a processing time of 6 minutes per
unit.
The third resource has a processing time of 5 minutes per unit.
With
a 40% probability, the flow unit coming out of the third resource
has
to be reworked. In that case, the operations at the second and
third
resources are repeated. You can assume that (a) rework always
succeeds (i.e. a unit going through the rework loop will always
work
after the third resource),and (b) the processing times for units
in
rework are the same as for regular units.

1- For every unit of demand, how many units have to flow through
the second step in the process?

2- Where in the process is the bottleneck?
Step 1
Step 2
Step 3