Successful Order Picking
Making your order fulfilment and picking as efficient as possible
Order picking and packing can be so simple that any employees and supervisors involved with this need only minimal training.
Order picking and packing can be so complicated and highly analysed that it has created an exceptionally competitive industry all of its own – third-party logistics (or 3PL).
For most people, order fulfilment processes will be somewhere in the middle. However, this isn’t to underplay its importance to any business.
In fact, Professor René de Koster (an eminent expert on the subject) says:
“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 in customer satisfaction with the warehouse – and in the final analysis the entire supply chain.”
So although order picking is effectively the process of taking items from your inventory (usually being stored in picking bins of some type) and preparing them ready for dispatch to your customers that have placed orders, there are a wide variety of ways that this can be undertaken.
Quick Reference / Contents
Defining Types of Picking
Before looking at ways to improve your order picking and packing, it is worth understanding that there are in fact numerous defined methods of order picking.
These have been developed to suit companies and inventories of varying sizes, different storage facilities, product types and even to tailor the processes to available labour.
The most common types of order picking are:
- Piece picking (picker to part)
- Zone picking
- Wave picking
- Sorting systems method
- Pick to box
These are covered in more detail below.
Piece picking / Picker to part method
Perhaps the most basic way of order picking, this method sees the order picker moving to collect the products / parts required for a single order.
In effect, your employee is sent around the warehouse with a list and a box or container, picking each item as they go.
Although this can be optimised to a degree (the picker can be sent on the most efficient route around the warehouse), in general, it is seen as one of the least efficient types of order picking.
Saying that it can work well for start-ups that have yet to grow their online sales, for specific industries, or for the handling of orders of oversized or unusually shaped / sized products that may require special handling processes.
Zone picking method
In the zone picking method, each individual order picker is assigned to one specific area or zone within your warehouse. They will then only pick orders / products that fall within this zone.
The picker will be responsible for their own area, picking the products that they are able too. If an order is not complete, then the order will be passed to the next zone, where the additional products will be added by the picker in that area.
Whilst this allows for greater efficiency and allows pickers to become much more familiar with where products are housed, a drawback (depending on how your inventory is arranged) is that certain members of staff may be busier than others. Those that may be less productive can also hold up orders and create bottlenecks during busy periods.
Wave picking method
Wave picking is similar to the piece picking method in that the order picker moves around the entire warehouse, but the difference is that they collect the products for several orders at once.
This method is prevalent in fashion and clothing fulfilment, plus a wide number of ecommerce operations, as it lends itself to picking where there are both a large number of SKUs and a high percentage that all appear very similar.
A good example of this is men’s trousers. When taking into account waist measurements, leg lengths and colour, there could be in excess of 30 SKUs for what is effectively a single product. Storing these in one location has been shown to dramatically increase the amount of mis-picked items, but wave picking allows for the different SKUs to be kept in seemingly random locations.
This ensures that items are not picked in error, and also eliminates the need for the picker to slow down to carefully read labels.
This method is therefore very accurate when setup correctly.
Sorting systems method
Usually reserved for larger operations, this method sees no actual movement of the order picker around the warehouse.
Products are brought to the picker using an automatic system (such as a conveyor). Items are placed on the conveyor in the storage area and the items are then sorted for a particular order. The operative in the picking area then simply collects the items and processes that order.
This method however is fully reliant on automatic material handling systems consisting of multiple conveyors and a number of sorting devices.
Pick to box method
Again, this method sees no actual movement of the picker around the warehouse.
A conveyor is also used that connects a number of picking stations, with the order picker filling a box on the conveyor with the products from his station that are required for the order. If multiple products from different stations are required, these are filled in turn as the box moves along the conveyor.
In effect, it is like zone picking, but with the box rather than the picker moving.
The advantages of this are not having multiple pickers moving around the warehouse (which increases health and safety risks), although the problem of certain stations potentially being busier than others can be seen if careful planning is not implemented.
Other picking methods
Although the methods listed above are the most commonly used, there are many variations that are used in specific markets or applications.
This can include cluster pick, carton flow rack and pick to light, although these are usually utilised where small efficiency gains can make substantial difference to a business’s success (think Amazon), or there are specific challenges such as space or labour availability to overcome.
And whilst upfront investment in such systems and methods is usually considerable, when factoring in the cost of labour, and an increasing need for picking accuracy (to avoid customer returns – which in in turn can affect their satisfaction), the cost can often prove worthwhile.
02: Order Picking Basics
The 6 basics of improving order fulfilment
Whilst there are numerous different ways to handle your specific processes, it is widely agreed that the 6 basics of improving order fulfilment are as follows:
- Organise stock
- Use picking bins
- Train and incentivise staff
- Keep picking zones safe
- Make better use of floor space
- Use efficient packaging
- Prepare for the unexpected
Whilst each of these areas can be sub-divided into what can become quite complicated and detailed topics (you can see advanced strategies to improve picking and packing here), the rest of this guide focuses on how you can ensure you get the basics right, giving you a platform for sales and revenue growth.
03: Advanced Picking Tactics
Advanced Tactics to improve picking and packing operations
Once you understand the type of picking you are currently using – or the type you would like to implement – you can further refine your processes through a number of methods.
Whilst some of these are specific to certain methods of order picking, the underlying principals are often good practice regardless of your setup, workforce or storage layout.
The 7 advanced strategies that you could use to improve your picking and packing are as follows:
- Not mixing SKUs
- Create a warehouse in a Warehouse
- Reduce travel times
- Assess vertical vs horizontal
- Analyse hit density
- Utilise storage strategies
- Minimise overall handling
Please continue reading for further information on each of these strategies to see if you can apply them to your business.
04: Not Mixing SKUs
Correct segmentation of inventory
This one is fairly simple. Mixing multiple SKUs in the same pick bin or location can affect picking productivity.
As mentioned in the wave picking methodology, if a location in a warehouse contains 5 – 10 SKUs, the order picker needs to stop to carefully identify the exact item they need for the order.
It has been reported that not only does this have a negative impact on picking accuracy, but can slow down the picking process by as much as 15 seconds for each item picked.
The knock on effect on productivity – and labour costs – means it is usually wise to have a discrete location for each specific SKU.
05: Warehouse in a Warehouse
Take advantage of the 80 / 20 rule
It is possible to gain a considerable amount of efficiency by using the 80 / 20 rule.
If you group the 20 percent of products that will typically make up 80 percent of your orders, it will cut down travel time for your picking team (if it is setup correctly to accommodate a high volume of activity).
This strategy works best if you are already employing sorting or pick to box methods, and can be effective for zone picking if the aisles are setup to allow for the high volume of traffic that will end up there.
It must also be noted that this does not really prove effective for wave picking processes.
06: Reducing Travel Times
Minimising fatigue and picking errors
Although it seems simple, it is surprising how often fatigue can play a part in picking errors. If your picking operatives have been walking all day – and are tired – they are more likely to make mistakes.
Travel time can easily account for between 50 and 70 percent of the pickers activities – so improving this also improves overall efficiency.
As such, it is wise to keep fast-moving products (i.e. that don’t stay in your warehouse for long) close to the shipping area. Grouping products that sell together can also help (think cameras and their cases).
Finally, making use of the wave picking method can also reduce overall travel time – particularly for multiple smaller orders.
07: Vertical vs Horizontal
Considering where slow moving lines are placed
For many, warehouse space – or lack of it – can hamper picking efforts.
Items that are picked from ground level (termed as horizontal) are much faster than items picked from parts bins that are higher up (deemed as vertical). Whilst this is unavoidable in a huge number of cases (for example parts distribution centres), it can be mitigated to a degree by placing the slowest moving items vertically (i.e. high up in the racking), and the lines with a greater velocity at floor level.
This way, your order picking team waste minimal time retrieving items from higher up.
08: Hit Density
Higher pick density for higher pick productivity
Order picking efficiency can also be improved through what is termed “hit density”.
For example, if a single order picker picks from one out of every hundred locations, then this will be considerably slower than if he / she picks from one out of every ten.
Effectively, a higher pick density will equate to higher pick productivity.
As a result, it can be wise to set up “hot zones” in your warehouse (similar to the warehouse in a warehouse principal) to concentrate the faster moving lines and speed up picking.
Many even give their inventory a label identifying their velocity (i.e. how fast they turnover), allowing strategic organisation of products to reduce picking times still further.
09: Storage Strategies
Density of products
Another perhaps obvious tactic is that of storage strategies.
For example, by using what is known as “slotting” (effectively using dividers within picking bins or locations) you may be able to improve the density of your storage, minimise accidents, reduce product damage and lower retrieval times too.
It is important to mention that your software must allow you accurately track all of the different locations and inventory statuses when doing this.
10: Minimise Handling
Reducing touch points
If possible, touch items only once.
This could see you focusing on reducing picking errors, or asking your operatives to pick straight into the packaging box instead of a tote (eliminating the unpacking and repacking back at the packing station).
An interesting idea is to think of everyone in the warehouse having wet paint on their hands. Every time an item is touched it leaves finger prints – and each set of finger prints costs your business money (in wages and efficiency).
As such, reducing the “fingerprints” will ultimately be reducing your costs.
See the benefits of enhancing your line-side containers?
Choosing the right tote or lineside container can be daunting – especially when there are so many options to choose from.
However, with careful thought on how and where the totes will be used, and the areas of your handling or supply chain you feel you need to improve, you can source a container that is an appropriate size, has suitable dividers and a number of other features that can drive efficiency in your business.
If you need any further advice or guidance on the best option for your specific application, then please do not hesitate to contact an adviser at GWP who will be happy to help with your requirement.