Swift and precise order picking with optical scanning systems
Even in times of increasing automation in logistics, manual picking of goods remains one of the key tasks. In many companies goods are still stored and retrieved by hand, not least due to the high degree of flexibility that the use of manpower affords. Yet the advantage of high flexibility when picking orders by hand is also accompanied by disadvantages; manual picking rates are much lower than those achieved with automated systems and there is also a higher risk of errors.
What chance does this old-fashioned-looking variant stand against the well-equipped, fully automatic retrieval system controlled by clever warehouse management software? Manual handling soon appears to come second best when products have to be stored and retrieved or goods have to be picked and prepared for shipping quickly while also guaranteeing high accuracy.
Yet there are helpful solutions that can come to the aid of humans here. Pick-to-light systems in particular frequently provide a way of at least leveling the playing field for man versus machine.
That’s because with the help of technology based on optical signals, which supports employees involved in the storage and retrieval of articles, picking accuracy of up to 100 percent can be achieved. Furthermore, visual signals permit faster access to the items being moved and thus a higher picking rate.
There are various ways of achieving this, depending on the level of investment and type of existing storage system. By way of example, the intralogistics supplier Kardex Remstar sets out the following options for its units:
LED info strip
One variant which is relatively simple to implement is the installation of an LED panel by the access opening of vertical storage lifts. Here the employees are shown on a narrow information strip which articles need to be removed and where they are located in the tray compartment that is currently open. This variant is comparatively easy to retrofit, but it does require an upgrade of the warehouse management software so that the necessary information can be displayed.
This system operates either with LEDs or a laser module, which is fitted above the access opening of a storage system in a way that allows it to move freely. The module shines a light down on the position where a particular article needs to be picked or placed. The direct light on the relevant position permits fast and precise access to goods. This system goes well with existing vertical storage lifts or shuttles.
A system has been specially developed for horizontal carousel units which uses LED signals to show the right level and compartment in which the article needed for the current order is located. The necessary equipment is generally installed between two carousel storage units and can supply both units with information.
This solution is relatively cost-effective because it can be easily integrated into existing systems.
Another simple solution primarily suitable for warehouses equipped with conventional shelving comes in the form of light indicators fitted in front of the individual compartments which show the warehouse employees the precise location of the articles required for the current order. Additional elements such as the number of units to be picked can also be displayed.
Data acquisition using camera systems
The integration of highly complex camera systems into intralogistics processes represents a step further compared to scanner technology using LEDs and lasers. If these devices are used in the area of incoming goods or order picking, much more information can be generated using their image recognition software compared to conventional light systems. Besides recording basic information on the location and number of articles, the camera can immediately capture additional data on the size and nature of goods and in some cases can even detect damage to the product. Scanning the article code is also possible, as is optical character recognition using OCR software. This makes it possible to capture entire texts with the help of the system. Processes can also be monitored more precisely with the help of photos, making it possible to increase efficiency in the warehouse using the evaluated data.
Since they do not require too much space, camera systems can generally be integrated into existing systems relatively easily and can also be used alongside existing pick-by-light modules.
This approach, developed in conjunction with TU Munich, involves the warehouse employee being given a pair of data glasses on which data relevant to the current order is displayed in real time. Similar to the principle used in systems such as Google Glass, the information is displayed in the user’s field of vision. The advantage of data glasses (also known as a head-mounted display, or HMD) is that users are still able to perceive their surroundings virtually unimpeded while data is projected onto the display. In this way the user receives a constant flow of virtual information about the type and nature of articles to be picked or their location. They also receive immediate notification when a picking error has occurred.
The main type of information displayed includes:
- Article number
- Number of items to be removed
- Location / shelf row
- Position of the compartment where items are located
- Verification of the picked article using a bar code scan
When the order picker moves around, arrows are displayed which show them the fastest route to take through the warehouse in order to reach the location where goods need to be stored or retrieved.
Yet the HMD is no one-way street where the warehouse employee is solely engaged in working through the tasks assigned to them. Instead, the order picker can also interact with the pick-by-vision system – either by carrying a data entry device or via voice command – and thus make changes.
Despite higher and more accurate picking performance, the disadvantage of the system is that the user needs a certain amount of time to get used to it and must be willing to embrace this technological change. The hitherto unwieldy size and weight of the devices could also have a negative impact on their acceptance. Yet with all the progress being made with communication systems of this kind, not least thanks to the preliminary work carried out by Internet giants such as Google and Amazon, it is likely that the glasses will have more manageable dimensions in the near future.