VARIETY OF ORDER PICK SYSTEMS

Order picking is employed in warehouses of every kind, from small, manually served spare-part warehouses of small firms to large, high-bay warehouses which serve as supply depots for a country.

The specification of the order pick system depends on many factors:

• the characteristics of the products, such as size, weight, quantity per carton, quantity per pallet, fragility, temperature needed for storage
• the sales volume of each product, and how this volume is distributed (many requests for small quantities or just a few requests for large quantities)
• the sizes of the orders in terms of number of products, total weight, total cubic volume
• the number of orders per day
• the methods of receiving products and shipping orders (full pallet quantities on full trucks, or mixed pallets on less-than-truckload (LTL) carriers, or cartons on package carrier trucks such as UPS or Federal Express)
• the costs and availability of labor
• the costs and availability of land and buildings

Major factors affecting OPS design are shown in the next figure:

In order to satisfy the main requirements properly, different types of functional areas (e.g., receiving, picking, sorting, unitizing, shipping, etc.) need to be specified, and different combinations of equipment types and operating policies are required.

The above considerations indicate that there are multilevel and inter-related design factors in OPS analysis and design.

A detailed discussion of factors affecting OPS design is available. (Yoon, Sharp, 1996)

These interdependent issues lead to a multifaceted problem that allows for a variety of feasible solutions. Where we narrow the search to economically efficient solutions, we often find competing solutions that are quite different from one another.