They characteristics in the modern system are,
- Flexible – able to meet the variable needs of a large customer base.
- Cost effective – able to operate on a low cost-per-dollar-shipped basis.
- High quality – the right product is available at the right time for the customer.
The main order picking concepts applied, in a warehouse are
- Pick-to-order – This is basically where a picker takes one order and travels through the whole warehouse (eg on foot or on a truck) until the whole order is picked. For example, in retail food distribution centres it is quite common for order pickers to take one or more roll-cage pallets and fill these with goods just for one store. The pickers may do this for goods located across the entire warehouse or just for their particular zone. Another type of pick-to-order is where pickers have separate compartments or containers for a number of orders on their trolley or roll-cage pallet. They may then pick-to-order for a number of orders simultaneously, placing goods for each customer into a specific compartment.
- Batch picking – The main disadvantage of a pick-to-order regime is that pickers typically walk the entire pick face for a single order. In situations where a typical order may only have a few order lines (ie only a few different SKUs being ordered) and where the product range is very large, then this would be very inefficient. It is therefore common, particularly for small orders, to batch these together and pick the total requirement of all the orders for each SKU on a single picking round. This method can achieve great benefits in terms of picking time, but of course the goods then need to be sorted at the end of the picking run into the different customer orders. This sortation may be undertaken either manually or using automated sortation equipment.
- Pick-by-line or pick-to-zero – Under this concept, the exact numbers of cases or items are presented for picking. For example, they may be brought forward from the reserve storage area or they may be specifically ordered from suppliers for cross-docking. In both instances, the unit load of one product line is picked to waiting customer orders (hence pick-by-line) and the picking continues until that line is exhausted (hence pick-to-zero).
In some situations it may be appropriate to make use of a combination of two or more of the above picking regimes within one picking system. A typical warehouse order will require just one or two slow-moving products, but a large quantity of fast-moving popular products. In this situation the picking area may be laid out with popular products near the dispatch area to minimize movement, with the less popular products, which require fewer picking visits, further away.
