Picking errors. How do you avoid them?
In many economic sectors, the receipt of goods and their handling in warehouses is an important part of the supply chain and also a key point in the organization of logistics activities. Due to the complexity of stock management operations and the diversity of goods stored, various problems, errors, delays affecting the loading and delivery of orders to customers can occur during picking.
What is picking?
The term picking refers to the activities involving retrieval of products from their warehouse locations (shelves/racks) for delivery of received orders. In the case of finished products being delivered to customers, picking refers to identifying, collecting and moving the required items to the areas where they are to be checked, sorted to order and packed for loading onto distribution vehicles. In the case of production plant warehouses, picking involves collecting raw materials and WIP and transferring them to workshops or manufacturing facilities for processing.
Picking is carried out in storage facilities both for outbound orders that are delivered to customers and for transfer orders, when products are delivered to other warehouses.
According to 6 River Systems, industry analysis shows that, on average, picking-related costs account for almost 55% of a distribution center’s operational costs. In addition, according to Supply Chain 24/7, 50% of picking time is spent travelling distances between locations.
Picking efficiency in warehouses is a priority for companies around the world as it has a significant impact on their brand image, profitability and customer satisfaction. Therefore, various actions and procedures to identify, prevent and reduce picking errors as well as to streamline activities are extremely necessary for continuous improvement.
In this context, logistics specialists have developed various solutions to reduce the time it takes to receive goods and take inventory, to coordinate and optimize movement of stocks, reduce travel and the distances covered daily by warehouse workers. These are software applications designed to help companies manage their warehousing activities and speed up the pace of goods deliveries.
Because picking generates the largest workload in a warehouse, Axes Software has developed a WMS system that includes a picking algorithm that may be configured according to the desired criteria, which sends tasks to workers on mobile computers and ensures picking by piece, box or pallet, generates labels for picked pallets and tracks picked items. These xTrack WMS implementations cover several types of picking: single order picking, zone picking, batch picking, wave picking, etc.
What are the main picking methods? What are their advantages and disadvantages?
Here are just a few of the most popular picking methods.
Sigle order picking
Single order picking is the simplest method of picking. Each picker is assigned only one order which they pick ‘start to finish’, taking the required products from the shelves at various locations in the warehouse. When all the items for an order have been picked, the worker is allocated another order.
This method has the advantage that the items for an order are generally picked as soon as it is received, but it also has some major disadvantages. The distances that pickers travel are much greater than they should be. Therefore, in addition to errors in the collected goods, delays may occur during the delivery flow. The picking pace is slow, labour costs are higher, productivity is low and more workers are needed for larger order volumes.
Implementing a WMS solution eliminates the main disadvantages of single order picking: optimizing picker routes by automatically determining the shortest picking route for each order and sending picking instructions (with details of items, quantities and their location inside the warehouse) to the mobile computers the workers carry contributes to a significant increase in the efficiency of the method.
Zone picking
Each picker is assigned an area (zone) and does not move around the warehouse (as in the case of single order picking, for example) to pick items from the orders they receive. Thus, they pick only the items that are in their zone. If other items are included in those orders, they are gradually collected by the other pickers in whose zones they are located. For this reason, this method of picking is also known as ‘pick and pass’. The box or trolley into which items are gradually placed by pickers passes through different picking zones until the order is completed. The boxes passing through these areas are often placed on conveyor belts.
In the case of the picking zone method there is only one order picking schedule per shift. Orders received by a certain time (cutoff) are picked during the current shift, and those received in the next time slot (after the cutoff) will be picked during the next shift.
The zone picking method allows easy stock management, but does not prevent human error, especially when high volumes have to be handled.
Batch picking
Batch picking refers to the picking of items, line by line, for several orders at the same time by a picker. In other words, pickers collect products with the same SKU for different orders allocated to them. The picked products will later be sorted and packed into individual orders in the packing area.
Batch picking has advantages when many of the orders “target” the same items, because the picker travels once to the location where a particular item is located and picks that product for all the orders in the batch. The main advantage of this method is the reduced picking time, which is reflected in increased productivity. The batch picking method is often used when the majority of orders have a few SKUs and the corresponding items are small.
Optimizing batch picking through WMS primarily involves grouping orders according to the items specified in them so as to reduce the distances pickers travel in warehouses and thus shorten order delivery times.
Wave picking
Unlike single order picking, in wave picking the items specified in orders are picked in waves. The customer orders received within a certain time frame make up one of the waves of orders that are picked simultaneously. Order picking is done daily in several waves, depending on the number of time intervals set, with limits linked to the time when the orders are received.
Thus, wave picking is a method of order processing that focuses on the time at which orders are collected and it is based on grouping products according to a variety of criteria. For example, orders can be grouped according to the driver/courier/carrier, customer or packaging required. After grouping, the items included in the orders are picked, but only at certain times of the day.
Team efficiency is improved primarily by reducing (or eliminating) downtime. The picking of a wave of orders is done at intervals of between 45 minutes and 2 hours, depending on the warehouse and the products to be picked. After picking, all products are taken to the area where they are sorted and grouped into individual orders.
Of course, as with other picking methods, efficiency largely depends on automating workflows. It can be improved by scheduling waves according to the delivery schedule, the couriers or carriers, or other factors. The advantages of wave picking are fewer bottlenecks, shorter distances to travel around the warehouse and timely deliveries, but processing can be cumbersome for urgent or last-minute orders.
As a general remark, when workflows are automated, the defining characteristics of each method are taken into account so that a real optimization of activities can be achieved. And the results may be easily seen in a drastically reduced number of picking errors, shorter delivery times, minimized operational costs and maximized profits.
Innovative picking technologies with Axes Software’s xTrack WMS
With the xTrack WMS warehouse and inventory management system, Axes Software offers its customers, in addition to the established ways of digitizing the picking flow, some innovative methods based on modern technologies:
- RFID (Radio-Frequency Identification) is recommended for receiving, delivery checks and inventory operations; it is efficient in situations where multiple items need to be identified simultaneously;
- Pick by Light is specifically designed for fast and efficient picking; it is no longer necessary to read information on mobile computers, the picking location is identified by LEDs (light-emitting diodes) that light up at each picking location;
- Pick by Voice is an interactive system based on voice technology (workers hear voice commands in headphones); it is efficient for both picking and sorting. It is a hands-free eye-free system (the workers no longer read instructions or hold mobile computers in their hands).
- Pick by Vision is an augmented reality-based picking technology whereby useful information is conveyed through a hologram on the lens of special glasses; it helps reduce human errors and effectively combines picking automation with the work of warehouse workers.
How do you avoid picking errors?
It is well known that errors of any kind, and especially picking errors, have a negative impact on productivity in the warehouse. In order to increase picking efficiency, you need to consider a number of elements, such as:
Picking method
Identifying the profile of the orders received at the warehouse helps you to select the most appropriate picking method(s). Adopting the right picking method(s) not only reduces errors but also shortens picking and delivery times.
Technology (software and hardware)
Most errors in warehouses can be eliminated by using a WMS system and mobile computers. The automation of warehouse workflows and the automated data collection and processing ensure traceability of items, elimination of paperwork, strict monitoring of stocks, avoidance of errors during the storage and order processing activities.
Technology plays an important role, for example, in the correct registration of items during the receiving process, as automatic data collection in the application via barcode scanners guarantees improved data accuracy. Errors during warehouse receiving are known to cause many of the subsequent picking and inventory errors. Accurate recording of received product details and quantities helps to quickly identify items for picking and maintain an accurate record of available stocks.
Item location in the warehouse
Classifying stored items according to their degree of popularity (ABC classes) is very important for the picking process. Placing products that are in high demand by customers on shelves (putaway) in easily accessible places in the warehouse reduces the distances travelled and the fatigue accumulated by the pickers who often end up making mistakes as a result. Also, placing items that are easy to mix up in different, but not close, locations significantly limits the risk of costly picking errors.
Causes of picking errors
Even if you have a WMS system in place and use mobile computers or handheld terminals, picking errors can still creep in (on a smaller scale, of course). Returns can often give you clues as to what caused them to occur. You may be surprised to find that it is not always the picker who is to blame. Errors can even be external (wrong data provided by suppliers, for example) and picked up as such during the receiving process. It is therefore advisable to periodically analyze the recorded errors in order to clearly identify their cause and to take corrective measures.
To identify the best software warehouse and inventory management systems, contact Axes Software specialists. By using modern technologies, you reduce picking errors, avoid mistakes in the organization of logistics activities and increase productivity across your entire company. Minimize storage and handling costs, reduce processing times for all types of orders and eliminate printed documents in your warehouse. Replace manual data processing with automation and human error, with logistics performance.
