This paper will focus on service parts’ supply problem in the overseas market which
is the major source of service parts revenue. The export amount of service parts in the
overseas market is over 100 million baht per month. Figure 1.3 illustrates the export
sales revenue from the year 2003 until mid 2006. The export is continuously
expanding whereas the service rate still has not improved. The low service rate is due
to the lack of an appropriate inventory system. Figure 1.4 illustrates the export first
fill rate during week 14-week 38 in the year 2006. The first fill rate ranges are
between 50-60%