Pick-by-Light
Pick-by-Light (in German about "picking according to light") is one of the "paperless" picking processes . Instead of a picking or picking list , the items to be picked and the quantities to be picked are transmitted to the order picker via a compartment display arranged directly on the picking compartment.
The synonymous terms Pick-to-Light or Pick-2-Light ( P2L ) are often used for the term Pick-by-Light . The term put-to-light describes the reverse process.
functionality
A pick-by-light compartment display consists of at least one eye-catching lamp that can be seen from afar and an acknowledgment button, which the picker uses to confirm the removal and to report the inventory change back to the warehouse management system in real time. In most cases, the compartment displays also have a numeric or alphanumeric display to show the picker the picked quantity and, if necessary, additional information. Correction keys (+/-) can be provided to correct the withdrawal quantity (for example in the event of a shortage) or for inventory functions, and additional function keys to call up special functions. As an alternative to acknowledgment via a button, sensors can also be used to monitor the intervention. Depending on the area of application, orders can be picked serially (after confirmation, the next compartment lights up) or in parallel (all compartments light up simultaneously) with a pick-by-light system.
Put-to-light
The term put-to-light describes the reverse process to pick-by-light. In this case, the order picker does not remove the item, but stores the item to be picked. The same compartment displays are used as with a pick-by-light system. Put-to-light systems are used in two-stage picking. To do this, several orders are first combined in a so-called “batch” and picked at the same time in order to save travel times and picking times. The articles are then distributed to the individual customer orders using the put-to-light system. One or more shelves equipped with compartment displays are installed at a distribution or sorting station. The order picker now scans the articles one after the other from the batch container. The compartment display of the associated distribution compartment then lights up. The order picker can assign and store the item quickly and safely.
Combined procedures
Both methods described above can also be combined for an additional increase in efficiency . For this purpose, a compartment display is installed on the back of the put-to-light distribution shelves. This shows the packaging employee which of the distribution compartments already contain all the articles belonging to the order, i.e. which have been fully picked. To do this, the eye-catching light (for example in green) is switched on. The packer removes the articles and confirms this with the acknowledgment button. The eye-catching light goes out and the compartment is free for the next customer order.
Mobile order picking systems
Pick-by-light systems achieve their maximum efficiency with short walking distances and high picking frequency per storage location. In the opposite case, for example a spare parts warehouse with long walking distances and low picking frequency per storage location, mobile picking systems offer a suitable solution. For this purpose, standardized or customer-specific vehicles are equipped with a power supply, WLAN connection, operator guidance and specialist displays.
The control software bundles a number of picking orders according to the number of available compartments on the picking vehicle. The order picker then “marries” the individual orders with the compartments on the vehicle. The operator guidance (visually via a display) guides the order picker with the vehicle from one picking point to the next in a route-optimized manner. The compartment displays on the vehicle show the correct storage compartment and the storage quantity. The storage is reported back to the host system via the acknowledgment button, and the next removal point is displayed via the operator guidance. A picker can pick several customer orders at the same time in a route-optimized trip. The number of orders depends on the volume of the articles and the design of the picking vehicle.
Connection of a pick-by-light system
In order to be able to take advantage of all the advantages of a pick-by-light system, the connection to the higher-level system (usually a warehouse management system or ERP program) is essential. The order data must be transferred quickly and securely, as must the acknowledgment, correction or special function messages. The procedures and processes must be well-defined in advance and usually adapted to customer requirements.
Advantages and disadvantages
advantages
- reduced search time
- direct feedback to the warehouse management system:
- Acknowledgment of removal
- Correction in case of shortage
- fewer picking errors in the form of incorrectly picked articles
- fewer picking errors in the form of overlooked articles
- with fewer errors, higher customer satisfaction and fewer returns
- extremely short training time, therefore high staff flexibility
- greatly reduced order lead times
disadvantage
- limited to one order per zone at a time, unless you work with different colors (one color per order and picker)
- an undetected failure of a display leads to errors in order picking, but modern systems recognize such failures independently. In addition, in the event of a display failure, the superimposed software recognizes that not all positions of an order have been acknowledged.
See also
- Voice picking (Pick by Voice)
- Pick-by-Vision
- Pick-by-Motion