Figure 8: % of reduction; a)Lead time, b)In-process inventory, c)Finished good inventory, d)Finished good area.
Lead time (manufacturing lead time) has been reduced as seen in 8(a). The lead time is reduced from 10.7 days
to 6.9 days. The reduction of lead time shows that it could response to customer need. Thus efficiency increases
and production process became easier by producing based on Kanban signal [2]. There are also significant
improvements recorded at inventory level, in which in-process and finished goods inventory were reduced by 52%
and 55% respectively (see figure 8 (b) and (c)). For in-process inventory, total of WIP was 4840 pieces, however
after the Kanban system was adopted the WIP decrease to 2321 pieces. Finished goods inventory was reduced
from 1780 pieces to 794 pieces. This resulted from the adoption of PIK card and PWK card that were used as
authorization of production. The production at both lines are initiated when kanban signal appear. The metric of
finished good area also decreased after introduction of kanban system. As shown in figure 8(d), the area
decreased from 504 square feet to 483 square feet. This resulted from replenishing those items that had been consumed by customer, not forecast number. Therefore, quantity of finished goods to store also has been reduced
as well as their area.
From the results and discussion at above, can be seen that implementation of kanban system at manufacturing
area would improve lead time, inventory and space. The improvement of three areas had enhanced
manufacturing capability in term of resource efficiency and low operation cost.