To include batches
in the analysis, click the Batch button on the
dialog. Batches are often associated with lots, so we select
the Setup time and Lot Size button. We include Resources and Time
The example has five operations arranged in series.
When batches are present the resource amount column contains
a formula that is:
Resource amount = 1/batch size
Two of the operations have batch sizes other than 1. The
first operation, Op1, has a processing time of three hours,
but the batch size of three indicates that three units
are processed at the same time. The resource use per unit
is 1/3, and the net effect on the use of Machine 1 is one
hour per unit. Op1 contributes three hours to the Throughput
Time and three units to the WIP. The transfer
lot size of 1 means the units enter and leave machine 1
one unit at a time.
The Furnace operation is different because it
processes batches of five. The lot of five units enters
the furnace altogether and they complete process in five
hours. The setup lot, transfer lot and batch size are all
the same. The operation contributes five hours to the throughput
time and 25 units to the WIP.