Pick-to-Light / Pick-to-Light :
The system for picking, assembly and production in 2021
What is Pick-to-Light / Pick-to-Light and when does it really make sense to use a Pick-to-Light system in order picking, assembly or production? Here we explain everything in detail, show you the hardware and software you need for the system. The best information, tips and tricks from the experts for paperless picking in 2021.
What is Pick-to-Light or Pick-to-Light?
Pick-to-Light, consisting of compartment displays, belongs to the paperless order picking methods and supports the order picker with light during order picking. The picking quantity is displayed directly at the storage compartment and confirmed at the acknowledgement button.
You can find out more about the definition here: Pick-to-Light / Pick-to-Light Definition.
Pick-to-Light (roughly "picking by light") is one of the "paperless" picking methods. Instead of a picking list, the items and quantities to be picked are communicated to the picker via a compartment display located directly at the picking compartment.Source: Pick-to-Light - Wikipedia
Pick-to-Light and pick-to-light are synonyms that we will continue to use only individually.
- Very short search time of the articles
- Hands free when picking and great freedom of movement
- Multilingual use with short training time for changing personnel
- Fewer pick errors from wrong items and no missing pickings
- Enables very high performance of the order picker and short throughput times
- Fast and accurate quantity correction directly at the storage location and direct feedback of the stock change to the warehouse management system
Without display and without quantity input.
Only one 7-colour LED, acknowledgement button and freely configurable function button.
Details for PTF-L-6.
Standard compartment display for many applications with numerical input of the quantity.
Details for PTF-3N-4
Zone display with touch screen and alphanumeric display.
Details for PTF-CTRL2
You can find the complete list of hardware here:
The Pick-to-Light hardware guides the order picker with light and consists of compartment displays, controllers and accessories. The picker has to find the display at the storage location quickly and without errors, read the quantity and confirm the removal of the products with the acknowledgement button on the compartment. List of all hardware components can be found here: Pick-to-Light Hardware
- Controller (communication and power supply)
- Mounting rails with integrated BUS (shown here in yellow)
- Compartment displays with signal lamps (2 x 7 colours), piece count display and an acknowledgement button
- Cabling with 4-core cable between the mounting rails and controller
In this article you will find the most important information about the picking process directly from the manufacturer. Why is the picking system so special and what are the error rates? What distinguishes the system from the other processes? How is a modern pick-to-light constructed? Where is it best used?
A Pick-to-Light system is modular and very flexible. It is easy to mount the displays at any extraction point. The functions are clearly structured and the light signals are unambiguous. The system supports various devices, such as barcode scanners, RFID readers, scales, etc. Nearly all displays are equipped with several additional keys to correct faulty stock (plus, minus and F-key for special functions). Some displays have only a simple signal lamp and acknowledgement button.
You can find more details in the article: Pick-to-Light System
- Sensor for automatic acknowledgement monitors access to the storage compartment (access monitoring).
- Digital I/O for receiving and transmitting external signals.
- Beep sound
The system is controlled by the LUCA software in real time. The connection to the warehouse management system, material flow and conveyor technology is made via the LUCA-Server, which controls the entire processes.
The pick-to-light sensor has an important new function in the removal confirmation. A sensor can be optionally installed above or below the compartment display. The sensor monitors the accesses and automatically confirms the activities. However, the goods to be picked cannot be counted with it. The automatic access control is based on modern TOF light sensors.
The mounting of the sensors must be precisely coordinated. The sensor as a light sensor can measure 15-20 cm without a reflection mirror. With a mirror, the sensor can even be used at 80-100 cm.
Application areas of Pick-to-Light
The following industries have been using our system for many years:
- eCommerce: picking warehouse, replenishment, sorting station in the dispatch warehouse
- Automotive: Batch processing and sequencing of baskets and JIT racks for the assembly lines
- Production: assembly stations, set formation and machine placement
The Pick-to-Light system is very versatile, supports the picker and avoids picking errors. The field of application is large. You can find out more details in the article: Where is Pick-to-Light used?
Pick-to-Light Process in order picking
Like all paperless picking processes, the Pick-to-Light process is based on a pick list with picking orders. The data is transmitted by the warehouse management system. There are many variants of the mode of operation.
What does a pick-to-light process work?
The pick-to-light process is the term used to describe the individual work steps in order picking. The process is very important for a picker, his performance and quality. The picker should be guided safely and quickly to his storage location with the help of the compartment displays. Picking errors must be reduced to an absolute minimum.
- The picking order is activated with a barcode scanner, RFID or automatically and picking is started.
- All displays with signal lights and quantity indicators light up.
- The picker leads the removal of the indicated quantities.
- The removal is acknowledged with the acknowledgement button directly on the storage compartment.
- After confirming the removal, the system switches off the compartment displays and automatically changes the stock quantity in the storage compartment.
The requirements for optimal access to a storage compartment are very different in the solution. The picker should quickly follow the light signal at the storage location, clearly read the quantities on the quantity display and safely perform the confirmation (short learning time and search time). The pick list does not exist and the picker has his hands free. This is a great advantage of the paperless picking system.
The standard process
There are standard packages at LUCA in which the Pick-to-Light process for picking in a warehouse already fulfils 80% of all requirements. The aim is to minimise the error rate and speed up the picking process. Very often, however, the requirements for the system are very specific. We integrate different solutions and also build the process customer-specific. The entire logical data processing is handled by our LUCA-Server.
How can the correct orders be started? Can the completeness of the last order also be checked? Basically, there are two different start methods here:
- Start via a receipt with barcode
- Paperless picking (FIFO or external trigger)
If the receipts, cartons or containers are marked with a barcode (1D or 2D), stationary or mobile scanners can be used in the Pick-to-Light process (scan). In this case, the displays can also be activated via the delivery note or invoice. RFID technology is also supported.
In the case of paperless processes, the process usually starts automatically, either from a data buffer or by automatically diverting the containers via a conveyor system. In both cases, the LUCA-Server monitors the individual processes and ensures the appropriate quality. In some solutions, the start of the next job is only possible when the previous job is completely finished. Should an error occur here, the system generates an error message.
Simultaneously, Sequentially or Page by Page?
If you have already started picking, the displays on the compartments must now light up. But what is the best way to light them up? All together, one after the other, first one and then the other side of a shelf aisle?
We achieve different goals with different methods. As a planner, you need to understand well the exact pick-to-light process at the storage compartment and choose the correct method, taking into account cognitive ergonomics. This point is very important when creating the systems. Take your time to find an optimal solution.
Although a display is very simple in principle, the process can be structured very differently. The control for this is taken over by a software module on the LUCA-Server. If necessary, we also use different techniques at the same time.
In the simple systems, all displays and signal lamps in a picking zone light up simultaneously. The order in which the goods are picked is then arbitrary. In other cases, we form a picking route and control the removals sequentially only after acknowledgement.
Confirmation of withdrawal and end of order
When all the items have been picked, the picker confirms the removal at the compartment with the confirmation button. If the quantity is not correct, the correction buttons (+/-) can be used. The confirmation of the pick triggers a feedback to the higher-level warehouse management system. There, the stock changes are carried out in real time.
Sometimes put-to-light displays are also used at a Multi-Order-Picking to support the put process in logistics. However, we describe this topic separately.
Pick-to-Light in assembly
The work in an assembly often consists of many steps in which the worker must correctly reach into many containers according to the assembly instructions. An assembly process with assembly instructions on a piece of paper is not optimal. The luminous displays can significantly increase performance and quality.
You can read more about this in the article: Pick-to-Light Assembly
How good is Pick-to-Light and how much does the system cost?
Performance and quality are opposing parameters. As a result, the more performance is expected, the less quality the picker can deliver and error rates increase. Increasing performance and quality at the same time is not easy with any of the picking methods. Faster and cheaper. That is the goal. The control software's ability to solve the problem is not everything.
As a leading order picking process, Pick-to-Light is currently providing us with an excellent example of how performance and quality can quickly increase through the use of light signals and how operator guidance is improved when stock is changed immediately.
Performance increases by up to 40%. Due to the targeted support of the accesses to the storage compartment, the quality also increases by more than 15%. This minimises picking errors and teach-in time. When using sensors, the quality increases by another approx. 10%.
The ROI calculation and the costs
When planning the system, it is essential to consider the economic viability and the increase in efficiency. The system requires a relatively large amount of hardware, which does not make the procurement of the equipment cheap. The cost of the projects is justified by the effort put into the hardware. As a budget, calculate with 100,- € per storage compartment.
An ROI calculation must show whether the investment is profitable for the company. Get in touch with us. We will help you make the calculations and explain the details. If the demand for power is not particularly high and the storage areas are large, we also supply other technologies as an alternative.
- Relatively high acquisition costs.
- Difficult to use with free-standing pallets (special construction required).
LUCA as a provider of the Pick-to-Light / Pick-to-Light systems?
As a manufacturer of picking solutions, LUCA Logistic Solutions, is very flexible thanks to the professional software of the LUCA communication server. We offer different technologies to achieve an optimal solution for the customer. Contact us to learn more.
In logistics and production, the pick-to-light system is one of the best and most widespread picking methods. The picker intuitively follows the light signals and quantity displays at the pick location and thus minimises his search time (operator guidance through the orders). Numeric and alphanumeric quantity displays show the number of items. In case of stock errors, the correction keys help.
The simple installation, robust acknowledgement buttons and flexible conversion options make the Pick-to-Light system very attractive. Easy connection to any warehouse management system via the LUCA-Server brings enormous advantages. The system can also support permanent inventory very well. Optimal operator guidance through customer orders is the goal.
However, in warehouses with many storage compartments, the price of mounting the displays is quite high. Therefore, it makes sense to use the system for A-items and support it for B- and C-items with other, cheaper technologies and picking systems. Put-to-Light can also be used on the vehicle with WLAN in order to optimise the gripping times, walking times, etc. during picking.
Many years of experience in paperless order picking
What hardware does Pick-to-Light need ?
For a Pick-to-Light system, the first thing you need are the compartment displays that are mounted at each storage location. They include LED lights, quantity displays and several buttons. Another system component you need are the controllers, which are used to supply the compartment displays with power and data. The last thing to add are the mounting rails, clamps and cables.
If you want to know more details, visit: Pick-to-Light.
What interface does Pick-to-Light have to SAP?
The SAP interface is not realised directly with the hardware, but via a server. The server communicates with the compartment displays on the one hand and with the higher-level system, e.g. SAP or warehouse management, on the other. The connection via a server can be designed flexibly with RFC, TCP/IP, databases, etc. Read more about this at: Pick-to-Light Picking
What specifications are required for a Pick-to-Light request?
- Number and types of compartment displays (see: Pick-to-Light Hardware)
- Number of mounting rails for attaching the compartment displays
- Total length of the mounting rails
- Layout and functional description
- Inputs to the host or warehouse management system
How does Pick-to-Light work ?
The Pick-to-Light compartment displays light up as soon as a picking order is activated. The indicator light signals the display position from a great distance. The withdrawal quantity is shown on the display. Correction is made with plus/minus keys, if necessary. The order picker confirms the removal of goods (pick) at an acknowledgement button of the compartment display.