To maintain competitive advantage, logistics service providers and retailers have embraced automated order picking in their warehouses by implementing pick-to-cart, pick-to-light, voice picking and other technologies. However, despite the success of these ICT solutions, considerably higher efficiency gains can be achieved by reorganising key logistics processes as well.
Jeffrey Verberne, Logistics Business Consultant at Zetes, takes a look at how businesses can implement a multi-order picking solution and how to avoid potential obstacles.
1. Identify the optimal order picking method
The optimal order picking method depends on many factors, such as the product range, peak period volumes, resource, warehouse size, number of customer orders and the desired delivery times. Without an analysis of these factors and identification of the key logistics bottlenecks, any investment in an automation solution will not yield optimal efficiency.
It is also important to determine which order picking method and underlying technology will provide the most benefits – either single- or multi-order picking, and pick-to-cart, pick-to-light, pick-by-voice, or another option.
2. Distinguish between dynamic or static order picking
To find the best order picking method, it is important to distinguish between dynamic and static order picking. So, let's breakdown the jargon:
Dynamic order picking
The operators remain in a fixed location and all of the ordered items are provided within their reach – for example, in a robotised warehouse. Dynamic order picking has the important advantage of eliminating all travel distances.
Static order picking
Each picker goes to the storage locations of all ordered items, either by foot or with a picking trolley or a forklift.
A further distinction with static order picking is between single- and multi-order picking. If most orders have a large number of SKUs, the travel times between the items are often short and single-order picking is probably the best solution. However, if there are only a small number of items for each order, then multi-order picking can yield considerable time-savings. It can also be necessary to pick several orders within a defined time window for customers or for a specific carrier, which is called wave picking. Finally, large distribution centres can be divided into zones within which staff pick orders based on zone-specific SKUs.
3. Assessing and minimising travel distances
The choice for single or multi-order picking can lead to considerable differences in efficiency. With multi-order picking, the primary goal is usually to minimise travel distances for all order pickers. This is done by picking all items for several orders (multi-order picking) on a single route, or by picking the total quantity of one specific SKU for several customers at the same time (batch picking).
With these two options, all picked items must also be assigned to the right customer orders in an intelligent manner. This is preferably done during order picking by using check numbers or colour codes and a separate roller container or shipping box for each order. If splitting the items after picking takes too much time or leads to errors, the potential efficiency improvement drops or the delivery reliability suffers. The efficiency boost that can be achieved with multi-order picking depends on the product range, the number of SKUs per order, the number of order pickers and the warehouse size – just like other methods – so it always has to be considered on a case-by-case basis.
4. Executing process analysis and business logic
For insight into the advantages and the savings that can be achieved with multi-order picking, it is always necessary to analyse the order handling and order picking processes.
Key questions to ask are:
• What are the current travel distances of all order pickers, and how many packages per hour do they pick on average?
• Is the product range or part of the range suitable for item-based or order-based multi-order picking, and does that fit within the time windows available for order picking?
For many small, individual orders, it is often not worthwhile to implement multi-order picking due to the expected delivery time, e.g. same-day delivery. However, the order streams of logistics service providers and retailers with more sizeable warehouses and dozens of order pickers are large enough that an investment in multi-order picking can usually be recovered within a short timescale. An important consideration to take in this regard is whether the existing ERP and/or WCS/WMS system has the capability to support multi-order picking. If the pre-existing systems don’t have the capability, it will also be necessary to introduce an additional business logic layer for calculation of the quantities and adjustments to a voice dialogue.
So how does this work in practice?
A.S Watson, the corporation behind Kruidvat, Trekpleister, ICI PARIS XL, Pour Vous and Prijsmepper, and thus the Dutch market leader in health & beauty is a great example of how businesses can benefit from up to a 38% efficiency boost by implementing multi-order picking.
Coen Mulder, Functional Control Supply Chain Development at A.S. Watson explains: “In our warehouse here in Heteren we have been using voice picking for several years, based on the ZetesMedea solution. Our order handling is split into three streams: all products in the current assortment, special-offer products, and e-fulfilment orders.
“After using single-order picking for a while, with all pickers travelling through the entire warehouse, we got together with Zetes to look at ways to minimise our travel distances. We came to the conclusion that we could achieve about 16% efficiency improvement by combining orders with the support of quantity calculations for taking along the best order carriers (pallets or bins). Based on the business case, we then jointly implemented multi-order picking.”
Speaking of the 38% boost in efficiency, Jacqueline van Oostrum, Supply Chain and Logistics Project Manager at A.S. Watson adds: “Along with the previously mentioned quantity calculations for our order carriers and expansion of the voice dialogue for batch picking, we also added a number of pallet trucks. Ultimately what determines the maximum achievable improvement is the combination of software and equipment adjustments, as well as the commitment of all employees.”
“We see that our implementation of multi-order picking for the current assortment exceeded everyone’s expectations, with an impressive 38% improvement in efficiency” - Jaqueline van Oostrum, Supply Chain and Logistics Project Manager
“Coupled with minimising travel distances, multi-order picking delivers additional time savings – for example, because staff don’t hinder each other or have to wait in the warehouse alleys. Looking back on this project, we see that our implementation of multi-order picking for the current assortment exceeded everyone’s expectations, with an impressive 38% improvement in efficiency. The average number of packages per hour picked in this order stream has risen from 90 to 125. In light of that success, we have also implemented multi-order picking for part of the special-offer products, with the aim of achieving similar improvements with this second order stream”, concludes Jaqueline van Oostrum.