Improving the performance of manual order picking in the warehouse: A case study

Nowadays, warehouses provide both keeping and protecting products and also help serving products to customers quickly. To deliver products on time, the products must be picked effectively in the warehouses. For that reason, the efficiency of order picking process becomes very important. Furthermore, order picking affects other warehouse operations and also affects the transportation of products to customers on time. The aim of this study is to decide on a storage allocation policy for minimizing the travelling distance while picking orders in a retail warehouse. In the study, firstly, the existing storage allocation in the warehouse is examined. Later, different storage allocation models are proposed and analyzed according to travelling distance while picking orders. In the proposed storage allocation models, the products are assinged to shelves according to class based storage policy in the first model, according to family grouping storage policy in second model and according to combination of these two storage policies in the third model. These three different storage allocation models are designed according to similarity of groups and ABC analysis. Group similarity means, similar products are stored close to each other, i.e water group and soda water group are stored close to each other. The stock output rate is used for ABC analysis. The products with the highest stock output rate are stored to close the depot. Additionally, in order to evaluate the performance of these three models, two routing policies, i.e. A star and Dijkstra's algorithm are used for picking the orders. By applying, the routing policies, the travelling distance for the existing and three proposed storage allocation models are compared statistically. According to the results, it can be stated that for warehouse under study in this thesis, the best storage allocation model is the one that was arranged according to combination of the class based storage policy and the family grouping storage policy.