Abstract: The traditional studies on slotting lack exploitation to the correlation of stock keeping units (SKUs). In a wave-picking zone-based dynamic picking system where the whole replenishment is periodic, the concept and calculation way of the SKU’s correlation strength are proposed, a mix integer program model for slotting to minimize the max pick wave make span among all zones is described. The storage allocation based on correlations (SABC) algorithm which is based on SKUs’ demand correlation and storage allocation based on random (SABR) algorithm which ignores the SKUs’ demand correlation are developed. The SABC algorithm sets the cube per order index (COI) solution as the initial solution; the slots interchange policy is proposed to reduce the pick wave make span by reassign the SKUs pair to the closed slots. The promising computational results show that the SABC algorithm has perfect convergence, and it needs much less CPU time than the SABR algorithm. The solution of SABC algorithm is better than both COI and SABC algorithm, the average improvement vary from 7.6% to 25.1% and from 1.36% to 14.5% respectively. As the correlation strength becomes stronger, there will be more improvements to the picking efficiency.

Key words: Load balancing, Picking efficiency, Slots interchange policy, Stock keeping units’ correlations, Storage allocation, Storage allocation based on correlations algorithm