Although it may appear to be a rather simple undertaking, optimising a warehouse’s picking and packing routine is a complex enigma. So complex, in fact, that it has spawned an entire market sector now said to be worth close to one trillion dollars. I am talking about 3PL or third-party logistics. It is a colossal industry, and it’s only getting bigger.
René (M.) B.M. de Koster is a professor of logistics and operations management at the Department of Management of Technology and Innovation at the Rotterdam School of Managerment, Erasmus University (RSM). Professor de Koster’s research interests are warehousing, material handling, container terminal operations, behavioural operations and sustainable logistics. Recently, in one of his papers, he spoke of order picking and the importance of picking efficiency in a modern warehouse.
“Measured in time and money – order picking is without doubt the most costly activity in a typical warehouse. It is also the activity that plays the biggest role for customer satisfaction with the warehouse – and in the final analysis the entire supply chain.”
So, whilst order picking and packing may appear to be the simple task of taking items from your inventory, storing them in pick bins of some type and then preparing them ready for dispatch to your customers, it is easy to understand why so much time and money has been directed towards solving the problem of wasted time in warehouses.
Before looking at how fulfilment operations or warehouses can improve their picking and packing process, it is worth understanding the variety of methods employed in warehouses across the globe. All with their individual benefits and pitfalls, they have been developed to suit individual warehouses. Some are optimised for space, some for product types and others for the size of products which are stored.
Piece Picking/ Picker to part method:
Piece picking is the most commonly used type of order picking in warehouses around the world. It is where a single employee walks around the warehouse with an order list and a tote box/ container. The employee will then pull each item off of the shelf, attempting to follow the most efficient route. Although this isn’t the most efficient method of picking and packing, it is by far the easiest in terms of logistics.
Zone picking is another commonly used method within fulfilment operations and retail warehouses. Each worker is assigned to a specific area or ‘zone’ in the warehouse. This worker will then proceed to only pick items which fall within their zone. If the order can not be completed by using the items just in the first zone, the first picker will hand the box to the next appropriate zone to complete to order. If it is a particularly large warehouse, it is not uncommon for 3PL companies to invest in a conveyor belt to deliver the box to the next zone.
This method is perfect for larger warehouses as it allows pickers to become very familiar with the products that are housed within their zone. Meaning that less time is wasted trying to locate items that the worker is not familiar with. However, there are drawbacks. Certain members of staff may become busier than others, meaning that bottlenecks can start to form in the warehouse during busier periods, resulting in orders being fulfilled at a slower pace.
Wave picking is not dissimilar from the ‘Piece Picking’ method. The worker moves around the entire warehouse picking orders as they go. However, they will fulfil multiple orders at once; usually pushing a trolley with them as they go.
This me thod is most commonly employed by ecommerce operations and fashion + clothing fulfilment. This is due to these types of industries dealing with an extremely large number of SKUs and a high percentage of items that appear to be very similar. For example, you might have one product line such as a pair of trousers, but under this one product you may have upwards of 40 SKUs catering for the variation of leg and waist lengths. Studies have shown that the number of mistakes made when items like this are stored together increases dramatically. Wave picking allows for similar looking items to be stored in seemingly random places, thus reducing the number of mistakes made. This configuration also means that the picker does not have to slow down and read labels in detail before taking the item off the shelf.
Sorting Systems Methods
Sorting systems methods tend to be reserved for large warehouses and large fulfilment operations as the method requires a large investment in warehouse infrastructure. This method means that the order pick does not actually move around the warehouse.
Products are delivered to the worker using a fully automated system, such as a conveyor belt. Some of which can be viewed at:
Items are automatically placed on the conveyor in the storage area and then sorted for the order as it arrives. The operative in the picking area then simply collects the items and processes the order for delivery. It’s faster, it’s much more efficient but it incurs a hefty start-up cost.
Other Picking Methods
The picking methods that are mentioned above are the most commonly utilised within the industry, however there are many other methods that have been devised for use in specific markets and applications. These can include variants such as ‘Cluster Pick’, ‘Carton Flow Rack’ and ‘Pick to Light’, however these are only used in environments where small efficiency gains can make substantial differences to a business’s profits, for example: Amazon or other large companies that deal with huge numbers of products each day.
As an emerging market that is continuing to increase in value year on year, it is certain that we will begin to see other methods being utilised to improve warehouse efficiency. Some companies have gone as far as investing in Warehouse Management Systems (WMS) or ERP systems to suggest the best routes and methods for picking or put-away. Technology such as RFID and Near Field Communication is also starting to become a popular way to improve the accuracy of transactions and reduce picking errors. The University of Arkansas recently conducted a study which showed that utilising RFID technology in a warehouse increased inventory accuracy by 27 percent in just 13 weeks.
Reducing waste through Correx Modular Pick Bins:
Sarcina Packaging have a long history of working with a variety of warehouse operations and fulfilment companies. One of the most effective methods we have found of reducing costs within these types of operations has been by upgrading the pick bins that are most commonly used, and frequently replaced.
Many warehouses make use of cardboard K bins and pick bins, usually sitting on racking to store individual SKUs after breaking down pallets. Although these are a good way of organising stock, the cardboard very quickly succumbs to natural deterioration of the fibreboard, due to general use, knocks and bumps. Cardboard also breaks down a lot quicker in environments that are naturally lit, as the UV light and heat essentially starts to compost the fibres.
Correx provides a great new alternative to traditional pick bins. Correx is a corrugated plastic board, fluted at 90 degrees to provide maximum strength. It can be creased, die cut and welded to produce pick bins, trays and cartons. The pick bins that Sarcina have produced for a variety of fulfilment operations and warehouses have been found to last upwards of 5 years, where the cardboard alternative may last fewer than 6 months. The cost savings can be monumental.
Correx Modular Pick Bins: The Right Solution For Cloud Fulfilment