Problem Description: In order to produce a hard
disk drive, many precision parts must be produced and
assembled. One of the most important parts is the motor
spindle shaft. This part must be machined by an automatic
machine which requires less effort from an operator.
Therefore, an operator is assigned to perform 3 different
tasks. The first one is a direct service to the machine such
as loading/unloading the work-part bin, inspection the
finished goods, correction minor machine problem and
reset alarm warning. The second task concerns an off-line
work-part preparation, counting and transporting the
finished work-parts. The last assignment is recording data
i.e. tool change and adjustment data, production output
and inspection data. It can be recognized that the operator
does not require attention to the machine at all time.
Consequently, one operator is able to service more than
one machine at a time. The total number of machines
which one operator can optimally handle without a
machine idle time is considered a machine cluster
problem.