Assignment of Stock Keeping Units to Parallel Unidirectional Picking

Abstract

An order picking system consisting of a number of parallel unidirectional picking lines is investigated. Stock keeping units (SKUs) that are grouped by product type into distributions (DBNs) are assigned daily to available picking lines. A mathematical programming formulation and its relaxations is presented. A greedy insertion and a greedy phased insertion are further introduced to obtain feasible results within usable computation times for all test cases. The walking distance of the pickers was shown to decrease by about 22 per cent compared with the current assignment approach. However, product handling and operational risk increases. OPSOMMING'n Stelsel vir die samestelling van bestellings wat uit 'n aantal parallelle, eenrigting uitsoeklyne bestaan, word ondersoek. Voorraadeenhede wat in distribusies gegroepeer word, word op 'n daaglikse basis in opmaaklyne toegewys. 'n Wiskundige programmeringsformulering en verslappings daarvan word aangebied. 'n Gulsige invoegingsen 'n gefaseerde gulsige invoegingsheuristiek word voorgestel om die probleem in 'n prakties uitvoerbare tyd op te los vir alle toetsgevalle. Die stapafstand van die werkers wat bestellings opmaak kon met ongeveer 22 persent verbeter word in vergelyking met die huidige benadering, maar daar was 'n toename in produkhantering en operasionele risiko.