(a) New rack layout design
Current rack layout of warehouse was redesigned. The
selective policy was adopted for new layout system. Multilevel
rack design was utilized in order to maximize storage
contents.
(b) ABC class-based storage
In this step, products were grouped into three classes;
namely A, B, and C. Class A represents the fastest movable
product class which contributes to about 60% of the
turnover, while the slowest movable products which account
for about 10% of the turnover is represented by class C. The
products were categorized based on quantity of order for
each item. Only 24 items of the chilled products were
subjected to ABC classification. From previous data, the
highest number of orders amounted to 252 pallets required
per day.
(c) Layout design and location assignment
The new layout was proposed, taking into consideration
the maximum space utilization and convenience in picking
product. The location was specified using class based
storage and linear programming. Rollers are to be
employed. Product items of similar types for each customer
were located near each other. The rapidly movable items
were designated to storage areas closer to the I/O door. This
way, the overall travel distance can be reduced.
(d) Development of mathematical model
Once requirements of all products were known, the
mathematical model was developed to determine
commodities location. Mathematical model developed here
was a special case of the general multi-commodity problem.
Based on linear programming, the mathematical model of
the problem can be formulated as follows;