Order picking is a crucial aspect of warehousing. To minimise costs and to provide good customer service, it’s important that it is done accurately and that the products are accumulated into shipments quickly and in good order.
With manual picking operations, it’s important that distributors put in place good systems and practices that allow them to meet accuracy and speed targets. Walking from one pick location to the next is said to take up 60% of a picker’s time. Reducing the time taken to pick orders will thereby improve picking efficiency. And to do this, a warehouse can employ either wave picking or batch picking. But which is best for your warehouse?
What is wave picking?
Wave picking is much like discrete order picking – where one order is picked, one SKU at a time. However, wave picking also has a scheduling window, so certain orders are scheduled to be picked at certain times of the day. This wave of orders can be determined by certain criteria. For example, orders might be grouped together according to the type of carrier they will be distributed by, or by the type of customer they are going to, or by the type of packaging that they require.
The benefits and drawbacks of wave picking
As wave picking controls exactly when orders are picked, it also affects the flow of goods in the warehouse – not just for picking, but also for replenishment, packing and despatch. The wave generally lasts between around 45 minutes and two hours and the timing is determined by a number of factors, including the outgoing vehicle schedule. A number of waves can co-ordinate to maximise picking and packing and to meet the distributor’s shipping schedule.
Waves can be allocated at different times to separate zones. This is necessary if a warehouse has zones that require a longer time for order picking than others. Also, a warehouse with specialist items – such as high security goods or those with strict temperature storage requirements – may need those SKUs to be picked just before despatch.
Another benefit of wave picking is that the picking cart can typically hold more goods than is the case with other types of picking. This is because items are not being split into individual orders, and so it is likely that they are more uniform in terms of size or shape.
One downside to wave picking is that once the goods for the wave of orders have been picked, the orders then have to be collated downstream and sorted down into individual orders.
What is batch picking?
Batch picking is where groups – or batches – of orders are picked at the same time. Again, picking is done one SKU at a time, but with batch picking, many orders will include the same SKUs. This means that the picker is only travelling to one location to pick one SKU, whilst fulfilling multiple orders. Minimising repeat visits to the same bin location reduces travel time and increases efficiency.
The benefits and drawbacks of batch picking
Batch picking multiple orders simultaneously speeds up the picking process by addressing the main disadvantage or a simple pick-to-order method. In discrete order picking, pickers have to walk the whole pick face for a single order and then return it to a packing station. This can be very inefficient, especially where there are orders with a small number of lines to pick from a warehouse with a large SKU range.
With batch picking though, pick rates can be boosted from 60-70 lines an hour for single-order picking to 200 lines an hour or more.
Conclusion: is wave picking or batch picking best?
Both wave picking and batch picking can improve efficiency and will therefore have a direct impact on productivity. But choosing the right picking method really depends on your warehouse and the profile of goods that you sell and stock. The best method will depend on the number of lines per order that you typically sell and how many SKUs you stock.
Batch picking is particularly good for warehouses that stock small items as it can drastically shorten picking times. Many small and similarly shaped goods can easily fit onto a picking trolley, so fewer journeys to the same SKU or same zone are needed.
But wave picking is far more efficient for companies with a larger number of SKUs. It can be considered the superior choice over batch picking where the batch method results in too much picking traffic. Here, the high numbers of pickers with trolleys or forklifts can combine to create too much congestion, which negates the time-saving aspects as workers have to avoid each other, or wait for another to complete a manoeuvre. So in these cases, wave picking is best.
If you would like some advice on the best picking method for your warehouse, or how to enable it within your ERP or WMS, call one of our warehouse consultants today on 020 8819 9071 or get in touch for a quote.