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Product allocation for an automated order picking system in an e-commerce warehouse

A data mining approach

Written by Alexander Dahl

Paper category

Master Thesis


Business Administration>Supply Chain & Logistics




Master Thesis: Warehouse and logistics Apotea 38000m2 warehouse is located in Morgongåva. The material flow in the warehouse is a typical process of an e-commerce company. The goods are received and put into storage. When a customer purchases an order, the product is selected and packaged. The parcels are sent to the sorting station, which sorts the parcels according to the freight forwarder handling the parcels. Then dispatch the package. Adding the A framework requires changes to the typical warehouse process. A-frame requires a replenishment warehouse taken from the main warehouse. The picking and packaging process is done automatically in the A-frame. After that, the package will be the same as the manual picking and packing order process. Warehouse logistics is shown in Figure 2.1. Apotea uses a random storage strategy. Any pallet that arrives can be placed in any vacant place in the warehouse. When warehouse operators store pallets in the warehouse, the placement of pallets is registered in the warehouse management system (WMS). WMS keeps track of where all pallets are located and uses it as a basis for guiding pickers. They use the picker-to-stock method for order picking, which means that the location of the inventory is considered fixed, and the picker will go to the inventory location to pick products. 2.3 A-frame The purpose of this study is to develop a product allocation method for the A-frame purchased by Apotea. The use of A-frame and Apotea will be introduced in detail. During the research period, Apotea has not yet fully integrated A-frame into their daily activities. 2.3.1 A-frame process A-frame is an automatic order picking system. Unlike the pick-to-stock method used by Apotea in its manual warehouse, the A-frame is fully automatic, that is, the picking process is completely completed by the machine. The feeding of the machine is done manually. The A-frame has distribution channels on both sides of the machine, and the conveyor belt runs between them in an "A" shape, as shown in Figures 2.2 and 2.3. These channels are repopulated from a replenishment warehouse composed of products stocked in A-frames. The replenishment warehouse is close to the A-frame, so the operator does not need to travel far to grab the item replenishment channel. The replenishment warehouse is purchased from the main warehouse. The order items are distributed on the conveyor belt. There is a double filling point at the end of the conveyor belt, which means that items can be distributed into small or large boxes. This is determined by the warehouse management system (WMS) connected to the A framework. When items are dispensed into the box, the machine shakes them to ensure that the items do not rise above the height of the box (called overflow), as this will hinder the sealing of the box. Each box leaving the machine passes through the conveyor belt. 2.3.2 The WMS connection to A-frame relies heavily on Apotea's WMS. Without proper support from WMS, it is impossible to pick orders from the A frame. WMS tracks which products are loaded on which channels. A-frame itself has no information about which channel contains which product. The A frame will be distributed from the channel sent to it by the WMS by request. If products are placed in multiple channels, WMS will distribute picking to as many channels as possible. WMS determines whether the order is picked and packed by the A frame. After the customer places an order, it is sent to WMS, and WMS will first check whether all the contents of the order are stored in the A-frame. If not, the order will be sent for manual pickup. If the A-frame can allocate the order content, check the size of the items in the order. If the order is too big for a big box, then it will be picked manually. If the size meets certain constraints, then WMS uses an algorithm based on the order quantity and product size to determine whether they should be allocated to the large box or the small box. 2.3.3 Replenishment The replenishment of the A framework is very important. If a channel is out of stock, all orders containing that specific product will be affected. A-frame is divided into several modules, each module has about 30 channels. When a channel is close to being out of stock, the light on the module will light up. This will remind the manual operator to perform repopulation on the relevant channel. The operator will turn around and grab the items from the replenishment point and put them into the aisle. Hiring operators in this event is the main operating cost of the A-frame. 2.3.4 Distribution channel The distribution channel can only accommodate one type of product and the number of products stored in the channel depends on the size of the product. When the order window passes through the distribution channel, the distribution channel ejects the product onto the conveyor belt. For instructions, see Figure 2.5. There are dispensing channels on both sides of the A frame, but only one side is shown in the figure. The dispenser in the A-frame cannot accommodate all products. The following is a list of requirements for items that can be stored in the A frame: Figure 2.6: Process of adding products to the distribution channel. In this example, the channel for adding products is too wide. The channel must be adjusted to make the product fit tightly. • It must be solid • It must be opaque • Its dimensions must be within the following range: – Length: 40-220 mm – Width: 20-120 mm – Height: 10-100mm – Weight: 10-800g • Must be earthquake-resistant • Yes Stacking • Must be rectangular or cylindrical. These requirements reduce the number of products that can be placed in the A-frame. Read Less