What is parallel picking?
Parallel picking means that a customer order is first divided into several parallel partial orders by the warehouse management system. Later, the partial orders are picked in parallel in the storage zones (picking zones) by several pickers and then combined into one order again.
Details and simple explanation of parallel processing
In the merchandise management system, the order-oriented entry takes place first. In order to optimise 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 totes or shipping cartons (according to the pick list) in the picking process. For the picker, the parallel partial order does not differ from a normal order.
Each item of the order is picked with the picking method used (e.g. picking with Pick-to-Light, Voice Picking, Pick-by-Point®, etc.). Goods are picked normally from the storage bin. To optimise the picking time in the process, the pick time, dead time and travel time should be as short as possible.
Once all the goods have been picked, the individual picking orders must be brought together again in the method. To save the distances, sorters or conveyor technology are often used for this.
Start of the parallel partial orders
To achieve an optimal start of the parallel partial orders, the material flow system must first calculate the optimal start time of the individual orders. Here, the order throughput times in particular must be taken into account. The aim of the optimisation is that all parallel partial orders are completed as simultaneously as possible and thus no waiting times occur.
Merging the parallel partial orders
Once parallel order picking is completed in the warehouse, the individual orders are brought together in an order-oriented manner. The distribution time should be as short as possible for the order picker. The following methods can be used for this:
- Picking methods for pallet distribution (put-to-point)
- Accumulation of the 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- Manual sorting of goods with MDE (very outdated and slow)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 brought together in an order-oriented manner, dispatch can take place. The selection of the optimal picking method is not covered in this article.
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 basic times by dividing the tasks among several order pickers.
- Optimal use of picking methods, such as Pick-to-Light, Voice Picking, Pick-by-Point®, etc. when picking partial orders.
Disadvantages of parallel picking
The disadvantages are defined as follows:
- The procedure only makes sense for large warehouses with many storage zones (picking zones) and many items.
- The distribution of customer orders to the sub-orders is not always optimally feasible due to the warehouse structure.
- High technical effort in merging the parallel orders.
Parallel picking is suitable for large warehouses with many storage zones and high automation (Pick-to-Light, Voice Picking, conveyor technology, sorter systems) for fast picking. Several order pickers can process a customer order at the same time. The merging of partial orders is time-consuming and must be controlled very much with the order picking by the material flow system.
Comparable picking processes
For comparison, read about the other picking methods: