Pick-to-Light – When things have to be done quickly and accurately

Published on: December 30, 2014 / update from: April 24, 2021 - Author: Konrad Wolfenstein

[In collaboration with Kardex Remstar – ADVERTISING]

Fast and precise picking with optical scanning systems

Even in times of increasing automation in logistics, the manual picking of items and goods continues to be one of the central activities. Not least thanks to the high flexibility in the use of human labor, goods are still stored and removed by hand in many companies today. But the advantage of a high level of flexibility in manual picking is also offset by disadvantages; Compared to automated systems, humans achieve significantly lower pick rates and are also more prone to errors.

So what chances does this seemingly old-fashioned variant have in comparison to the upgraded provisioning systems that are fully automatically controlled by sophisticated warehouse management software? Especially when things have to be done quickly when storing and retrieving products or when picking and preparing goods for dispatch and at the same time a high level of accuracy is required when picking, manual handling seems to easily fall behind.

But there are solutions that can help people here. Especially with the help of pick-to-light systems, there is often a way to at least compensate for the disadvantage of humans compared to machines.

Picking accuracy of up to 100 percent can also be achieved with the help of technology based on optical signals, which supports employees when storing or retrieving items. In addition, the visual signals enable faster access to the parts to be moved and thus an increased pick rate.

Depending on the investment volume and type of existing storage system, there are different ways in which this can be achieved. The intralogistics provider Kardex Remstar, for example, lists the following options for its devices:

LED information band

A relatively easy to implement variant is to install an LED panel at the removal opening of vertical storage lifts. Here, employees are shown on a narrow information tape which items are to be removed and where they are located in the shelf compartment that has just been opened. This variant is comparatively easy to retrofit, but requires an expansion of the warehouse management software associated with the innovation so that the required information can be uploaded.

Light or laser beam

This system operates either with LED lights or a laser module, which is movably attached above the removal opening of a storage system and uses a light display from above to indicate the position from or into which an item should be placed. The direct light pulse on the location to be selected enables particularly quick and precise access. This system can be easily combined with existing vertical storage lifts or shuttles.

For carousel warehouses

A system was developed specifically for horizontal carousel warehouses in which LED signals are used to display the correct level and the appropriate compartment in which the item of the current order can be found. The devices for this are usually installed between two carousel storage units and can provide the two units surrounding them with the information.

This is a relatively inexpensive solution; This can be easily integrated into existing systems.

For shelving

Another simple solution, which is particularly suitable for warehouses that are equipped with conventional shelving, are light displays mounted in front of the individual compartments, which show the warehouse worker exactly where the items in his current order are. Additional elements such as number of units to pick can also be displayed.

Data collection using camera systems

A further step compared to scanner technology using LED and laser is the inclusion of highly complex camera systems for intralogistics processes. If these devices are used in goods receipt or order picking, much more information can be generated using their associated image recognition software compared to conventional light pulses. In addition to the mere location and number of items, the camera immediately records additional data on the size and condition of the goods and may be able to detect damage to the selected product. Scanning article codes is also possible without any problems, as is plain text recognition using OCR software. This makes it possible to capture entire texts using the system. The photos can also be used to monitor the processes more closely and thus offer the opportunity to increase efficiency in the warehouse using the evaluated data.

Due to their very small space requirement, camera systems can usually be integrated into existing systems relatively easily and can also be used as a supplement to existing pick-by-light modules.

Pick by vision

In this approach, which was co-developed by the Technical University of Munich, the warehouse worker is provided with data glasses whose display shows relevant data about his current order in real time. Similar to the principle of systems such as Google Glass, the facts are displayed in the user's field of vision. The advantage of data glasses (also head mounted display, called HMD for short) is that the user can continue to perceive the surroundings almost without interference in addition to the data projected on the display. In this way, the employee constantly receives virtual information about the type and condition of the items to be picked or their location. He also receives immediate feedback if he has made a picking error.

The main information recorded is, for example:

• item number
• Number of parts to be removed
• Location/row of shelves
• Location of the removal compartment
• Checking the grabbed item using a barcode scan

If the order picker sets off, arrows appear to indicate which route he should take through the warehouse in order to get to the place of storage or retrieval as quickly as possible.

But the data glasses are not a one-way street on which the warehouse worker is only busy completing the tasks assigned to him. Instead, the order picker can interact with the pick-by-vision and make changes using either an input device or voice control.

In addition to increased and more precise picking performance, the system has the disadvantage that it requires a certain amount of time for employees to get used to it and to be willing to adapt to this technological change. The currently rather unwieldy size and weight of the devices could also have a negative impact on acceptance. But with the ongoing development of such communication systems, not least thanks to advance preparation by Internet giants such as Google or Amazon, it can be assumed that glasses will be of a more manageable size in the near future.