Order picking techniques

If multiple orders are processed by an order picker simultaneously, we call this multi-order picking Goods are often retrieved from the provisioning units in an item-focused manner and then discharged into the respective order container, such as a K-trolley, in an order-focused way. If the items are ordered picked directly into a shipping box and packaged, we call this a pick-and-pack system. This requires order and item-focused volume calculation in order to determine the shipping box.

A variety of information is processed when order picking: pick lists, paperless order picking and automatic order picking machines. For order processing, the following activities apply information intake; access; acknowledgment or confirmation. A picklist (paper order picking) provides the order picker with instructions in the shape of an order picking list, such as in a shelving rack (collation of retrieval positions).

From this mostly route-optimized list, the order picker collects the relevant items in the given order. The picklist is the most prevalent method of information sharing, and is often sufficient, but has the disadvantage of resulting in reading errors and low order picking quality (especially for lots of pick positions).

Paperless order picking is a partly automated order picking system. 

The difference from the picklist is the online communication as operator guidance. This is shown through the following features:

  • mobile data capture with data terminal 
  • pick-by-light system;
  • pick-by-voice system;
  • pick-by-balance system

Paperless order picking consists of the following components:

  • main terminal;
  • senders and receivers, numbers depending on the size of the warehouse;
  • stationary or mobile terminals with keyboard or wand;
  • codes on the items, such as barcodes.

Paperless order picking can achieve:

  • high order picking performance through the direct display of retrieval quantities per item at each retrieval station;
  • low fault rate, as pick lists, cannot be mixed up, nor reading mistakes be made through getting rows mixed up;
  • a current, transparent order monitoring method through an online connection to a warehouse management terminal.

Mobile data terminal Here, the sender or receiver machine of a vehicle is connected to the main terminal using infrared or radio transmission. The main terminal, which contains information on quantities and storage data of existing items, takes over the order picking assignments, arranges them optimized for time and route, and transmits them online through infrared/radio transmitters to the terminal displays or a handheld machine with a keyboard, scanner, and display. The data is read by the order picker in the display or dialogue system that has been implemented and the completed pick/order confirmed.

Pick-by-light system in a shelving rack, each storage space is equipped with an alphanumeric or numeric display, which is placed above or beneath the provisioning location and connected to a server. This display consists of a unit, which provides the order picker with the quantity, and a confirmation button. The retrieval quantity can be adjusted either up or down through a correction button. Personnel and disruption data can also be requested. When an order picking assignment is entered using a barcode into the shelving rack, all compartment displays of the relevant items for order picking light up. Once the retrieval has been confirmed by the order picker, the light goes off again. This guarantees a simple check on order picking. Two-tone displays are used, when two order picking assignments are processed simultaneously by one or two people parallel.

Pick-by-voice system Transmission of picking and confirmation by voice command. It consists of the Talk man with strap, headset and charger. The order picker is voice-led, and voice picking keeps both hands and eyes free, multiple order pickers can work simultaneously in one aisle without paper. Voice recognition has reached an advanced level, is quick and reliable, independent of dialects or accents, filters sources of noise and supports the vocabulary.

This system is used in areas of order picking, such as cold stores, where thick gloves are used for work, making it hard to operate keyboards. LCD displays also face limitations of radio transmission at temperatures below –28°C.

Pick-by-balance system This order picking system is a combination of pick by- light and precision scales with counter function, which are situated under each storage container. For incorrect retrieval (too little or too much), the weight discrepancy is noted and a red light, as well as the remaining quantity, is shown on the display. An automatic confirmation goes through if the weight of the retrieval is correct. This continuous monitoring guarantees exact stocks prevents mistakes and reduces inventory checks.

Summary Machines used for scanning and order picking in logistics are sophisticated, usually in practical ergonomic sizes, and are relatively lightweight (approximately 300 to 500 g). They also reliably and quickly (approximately 36 scans/s) capture complex information. The reading distance is up to 1 m, the frequency is between 400 MHz to 2.4 GHz.

Each machine has individual strengths and features:

● reach truck with the manual scanner: 

● goods receipt and order picking truck with the data radio terminal

Source: warehouse and transportation logistics system.