Top picking strategies to maximise warehouse efficiency
Although many companies have introduced full automation with robots doing the work of humans, it is not a model that is suited to every warehouse. In reality, once the business case is fully evaluated, it is often too costly for all but the largest DCs to introduce full automation.
One of the biggest problems running a warehouse these days is recruiting and retaining good operatives. Despite what you may have heard this is not just because of Brexit, skilled warehouse workers have been in short supply for quite some time now and the recent Covid driven explosion in online trading has further exacerbated the issue as e-commerce shopping habits have become firmly embedded in the country’s psyche. Wage rates for warehouse workers are steadily increasing as employers compete for a limited labour pool. It is not surprising then that so many companies are wondering whether or not to simply bring in the robots. If only things were that simple.
Warehouses have proved to be a good fit for automation because the tasks associated with warehouse operations are typically highly repetitive, specific and measurable. Although many companies have introduced full automation with robots doing the work of humans, it is not a model that is suited to every warehouse. In reality, once the business case is fully evaluated, it is often too costly for all but the largest DCs to introduce full automation.
For picking operations especially, using humans instead of robots and having warehouse processes run through a warehouse management system (WMS) is still the most efficient and cost effective approach. Industry data consistently estimates that picking is the largest cost centre in a warehouse and can constitute over half of all fulfilment centre costs, according to a study conducted by the University of Chicago.
In addition to being expensive, warehouse picking is the activity that most directly touches the customer, since pickers are selecting the goods within a sales order to dispatch. Getting it right first time is therefore an imperative. Picking mistakes such as sending the wrong item, omitting items from a order, or sending the wrong order quantity, directly impact customer satisfaction, business reputation and profitability, so finding methods to improve picking activities is always a top priority.
Another cost drain in the warehouse is walk time – the amount of time that associates will spend travelling from location to location to pick items. Our experts in warehouse consulting estimate it accounts for about 50% of total pick time and without careful warehouse layout optimisation it can represent a significant level of waste.
Choosing the right picking strategy can make or break efficiency in the warehouse and significantly control the amount of walk-time required. WMS can help to shape the right approach and help you implement the most efficient picking strategy. Depending on the availability of human resources, the number of SKUs in stock, order volumes and complexity of order fulfilment, there are different options to consider – like wave picking and voice directed picking. Here are some of the most common types of picking:
- Zone Picking is often employed in warehouses that have to compile complicated orders with lots of component items, or inside large warehouses that have long walk times. In a zone picking environment, stock is organised into “zones” and an operative is assigned specific SKUs to pick. Rather than wasting time moving from location to location, only the bins and totes used to collect stock pick items for orders are moved from zone to zone, therefore maximising efficiency levels.
- Discrete Picking is effectively the opposite of zone picking because workers are required to compile each inventory item in a set order, one by one. It is most likely to be employed in warehouses with a small team fulfilling simple customer orders. The advantage is that it minimises the number of touches needed to complete an order, so it is a good option where appropriate to create a Covid safe warehouse.
- Batch / Multi-Order Picking is employed in high volume environments required to fulfil many orders each day. Here, orders are reviewed for their commonality and organised into batches by SKU. Pickers then target the best locations in the warehouse to complete as many orders as quickly as possible. Batch picking is typically employed in e-commerce environments, or where businesses can predict high volume items easily.
- Cluster Picking involves a single picker compiling multiple orders simultaneously across a variety of SKUs. This method is best reserved for experienced pickers or in warehouses that have voice directed technology in place to support the worker with spoken commands.
- Wave Picking is usually found in high throughput warehouses carrying a wide variety of stock items. Stock is picked in waves according to shipping priority rather than just when the order was placed. Shipments are then dispatched throughout the day according to their urgency. It is commonly found in warehouses offering a range of delivery priority options.
One of the best reasons why it makes sense to use humans rather than robots, is that they are actually more flexible. Given the wide array of picking strategies available, a warehouse can literally ‘pick and choose’ the best model for their current situation and implement changes very rapidly. In contrast, making changes to a robotic system is less flexible.
Robots entirely replacing humans in the supply chain is much further away than some might have us believe and when a warehouse is run through a WMS, this provides a high degree of automation whilst retaining the ability to stay agile and flexible.