Abstract: A research is conducted on the zoning problem of part distribution picking area for assembly lines with pull production. In such a set parts supply (SPS) distribution mode, to balance the picking time of each zone and identify production tact (TT), a mathematical model containing TT is established. By solving this problem to minimize the objective function, the optimal number of zones is obtained. Then, a heuristic algorithm is put forward. It optimizes the part picking frequency and sequence. By this method, it presents a rule to determine the location distribution. At last, an exemplary research is made. For this example, when TT is 160 s and 80 s, the result shows that the above two objectives are realized in reasonable error. Thus, with the changing of TT, one can flexibly change the number of picking zones. The proposed method provides a theoretical reference for decision-makers to realize shojinka in job site and reduce picking cost. 

Key words: set parts supply (SPS), flexible zoning, picking frequency, heuristic methods