What is parallel picking?

Parallel picking means that a customer order is first divided into several parallel sub-orders by the warehouse management system. Later, the sub-orders are picked in parallel by several pickers in the warehouse zones (picking zones) and then combined again into one order.

Details and simple explanation of parallel processing

Order-oriented entry is first carried out in the merchandise management system. In order to optimize the total picking time (picking performance), the customer order is divided into several storage areas in parallel in the warehouse management system and prepared as a partial order.

Each order is then picked in parallel in separate picking areas by several pickers in containers or shipping cartons (according to the pick list). For the picker, the parallel partial order is no different from a normal order.

Each item in the order is picked using the designated picking method (e.g., pick-by-light, Voice Picking,^{Pick-by-Point®}, etc.). The goods are removed from the storage location in the normal manner. To optimize the picking time in the process, the picking time, dead time, and travel time should be as short as possible.

Once all goods have been picked, the individual picking orders must be combined again in the method. Sorters or conveyor technology are often used for this purpose in order to save distance.

Start of parallel subtasks

In order to achieve an optimal start for parallel sub-orders, the material flow system must first calculate the optimal start time for each individual order. Order throughput times must be taken into account here in particular. The aim of optimization is to ensure that all parallel sub-orders are completed at the same time as far as possible, thereby avoiding waiting times.

Merging of parallel sub-orders

Once parallel picking in the warehouse has been completed, the individual orders are consolidated according to order. The distribution time should be as short as possible for the picker. The following methods can be used for this purpose:

• Picking methods for pallet distribution (put-to-point)
• Accumulation of goods with a flow rack (optimal picking method: put-to-light)
• Manual sorting of goods with MDE (very outdated and slow)

Once all items have been consolidated according to the order, they can be shipped. This article does not cover the selection of the optimal picking method.

Advantages of parallel picking

Depending on the structure of the supporting picking systems, parallel picking has the following advantages:

• High performance through order-oriented picking in separate storage zones (important: correct ABC analysis).
• Short base times by dividing tasks among several pickers.
• Optimal use of picking methods such as pick-by-light, Voice Picking,^{pick-by-point®}, etc. when picking partial orders.

Disadvantages of parallel picking

The disadvantages are defined as follows:

• The process only makes sense for large warehouses with many storage zones (picking zones) and many items.
• Due to the warehouse structure, it is not always possible to divide customer orders into sub-orders in an optimal manner.
• High technical effort involved in merging parallel jobs.

Conclusion

Parallel picking is suitable for large warehouses with many storage zones and a high degree of automation (pick-by-light, Voice Picking, conveyor technology, sorter systems) for fast picking. Several pickers can process a customer order at the same time. Consolidating partial orders is complex and must be carefully controlled by the material flow system during picking.