WAREHOUSE CHARACTERISTICS

WAREHOUSE CHARACTERISTICS

In order to provide a characterisation this section may be viewed, process, resources and organisation. Product arriving at warehouse subsequently are taken through a number of steps called processes.

Resources refers to all means, equipment and personnel needed to operate a warehouse, finally organization include all planned and control procedures used to run the system.

WAREHOUSE PROCESSES

The flow of item through the warehouse can be divided in several distinct phase or processes.

1. The Receiving Process is the first process encountered by an arriving item. Product arrive by trucks or internal transport. (in case of a production warehouse). In this step, the product may be checked or transformed.

2. In the storage process tem are placed in storage location. The storage area may consist of two parts. The reserve area where products are stored in the most economical way (bulk storage area) and the forward area where products are stored for easy retrieval by an order picker, product in the forward area are often store in smaller amounts in easily to access storage modules.

3. Order picking refers to the retrieval of items from their storage location and can be performed manually or (partly) automated in succession, these item may be transported to the sorting and / or consolidation process. Consolidation here refers to grouping of item destined for the customer at the shipping area, orders are checked, packed and eventually loaded in trucks, trains or any other carrier.

WAREHOUSE RESOURCES

A number of resources can be distinguished for an extensive review.
1. The storage unit, in (or on) which products may be storage units are pallets carton boxes and plastic boxes.

2. The storage system: this may consist of multiple subsystems that store different types of products, storage system are very diverse; they may range from simple shelves up to highly automated system, containing automated cranes and conveyors

3. The retrieval of items from the storage system can be performed manually or by means of pick equipment.

4. Other equipment that support the order picker are called order pick auxiliaries, for example bar code scanners.

5. A computer system may be present to enable computer control of the processes by warehouse management system.

6. The material handling equipment for preparation of the retrieved items for the expedition include sorter system, palletizers and truck loaders.

7. Finally personnel constitutes an important resources, since warehouse performance largely depend on their availability.

WAREHOUSE ORGANIZATION

In this subsection, we discuss organizational issues in a warehouse.
1. The far most important decision concerns the definition of the process flow at the design stage. For example: the decision of use a separate reserve area since this implies that a replenishment process will be part of the warehouse operation, the retrieval of item in batches or the splitting of the pick area in zones which both require a sorting process and / or consolidation process or the use of separate storage and retrieval aisles.

Furthermore some process require specific organizational policies.
At the receiving process, an assignment policy determines the allocation of trucks to docks.

At the storage process, items are transported to the storage system and are allocated to storage location.

Several storage policies exist. A dedicated storage policy prescribes a particular locations for each product to be store, whereas a random storage policy leaves the decision to the operator. Correlated storage or family grouping, aimed at storing products at nearby position if they are often required simultaneously.

At the order picking process (part of) orders are assigned to one or more order pickers. Various control problems deserve attention here.
Firstly, the total pick area may be divided into picking zones, to be served by different order pickers, through a zoning policy.
Two alternative policies exist parallel or sequential zoning second, order are pick one by one (single order picking) or in batches (batch picking) if batch picking is selected this directly implies that the pick orders must be sorted. Again two sorting policies exist: pick and sort (sequentially) and sort while pick (simultaneously).

Third, a routine policy may be define the sequence of retrieval and the route to visit the retrieval location.
Finally a dwell point policy may be prescribe, the position of idle order equipment.

If consolidation and sorting process is present, order are allocated to output lanes by a sorter lane assignment policy.

At the shipping process, orders and trucks are allocated to docks by a dock assignment policy.

Finally, allocation of tasks to personnel and equipment are addressed by operators and equipment assignment policies.