Manufacturing lead time is the time required to acquire, manufacture, or ship goods1. It includes
the time required for preprocessing, processing, and postprocessing of a finished product2. The
formula for manufacturing lead time is:
Manufacturing lead time = Preprocessing time + Processing time + Postprocessing time
Preprocessing time is the time needed for handling the order, making sales order, and preparing
supplies2.
Processing
time
is
the
period
when
the
product
is
manufactured
or
collected. Postprocessing time is the time of delivery2.
In this question, we are given the following information:
The product is Item A, which requires Operations 10, 20, and 30 in a work cell
The order quantity is 10 units
The operations require no set up time
The processing times for each operation are:
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To find the shortest manufacturing lead time, we need to assume that the preprocessing and
postprocessing times are zero, and that the operations can be performed in parallel. This means that
the work cell can process 10 units of Item A simultaneously, without any waiting or transportation
time.
Therefore, the shortest manufacturing lead time is equal to the longest processing time among the
three operations. Since Operation 10 has the longest processing time of 1 hour per unit, the shortest
manufacturing lead time is:
Manufacturing lead time = 1 hour x 10 units = 10 hours
However, this answer is not among the options given. Therefore, we need to consider another
possibility: that the work cell can only process one unit of Item A at a time, and that the operations
must be performed in sequence. This means that each unit of Item A must complete Operation 10
before moving to Operation 20, and then to Operation 30. In this case, the shortest manufacturing
lead time is equal to the sum of the processing times for all three operations multiplied by the order
quantity. Therefore, the shortest manufacturing lead time is:
Manufacturing lead time = (1 hour + 0.5 hour + 0.5 hour) x 10 units = 20 hours
However, this answer is also not among the options given. Therefore, we need to consider one more
possibility: that the work cell can process one unit of Item A at a time, but that the operations can be
performed in parallel with overlapping times. This means that as soon as one unit of Item A finishes
Operation 10, it moves to Operation 20, while another unit of Item A starts Operation 10. Similarly,
as soon as one unit of Item A finishes Operation 20, it moves to Operation 30, while another unit of
Item A starts Operation 20. In this case, the shortest manufacturing lead time is equal to the sum of
the processing times for all three operations plus the processing times for each operation multiplied
by the order quantity minus one. Therefore, the shortest manufacturing lead time is:
Manufacturing lead time = (1 hour + 0.5 hour + 0.5 hour) + (1 hour + 0.5 hour + 0.5 hour) x (10 units -
1) = 12 hours
This answer is among the options given and it is the shortest possible manufacturing lead time under
these assumptions. Therefore, the correct answer is B. 12 hours.
Reference : Manufacturing Lead Time; How to Calculate and Reduce Lead Time; How To Calculate
Lead Time?; What Is Lead Time? How to Calculate Lead Time in Different Industries.
