A watch manufacturing company in Switzerland is considering the number of trays it must deploy in its manufacturing process. Watches are hand-assembled by a team of experienced watchmakers and sent in a purpose-built watch holding tray for quality assurance.
Each tray can hold 30 watches. The quality professional first examines the dial, sets the time, and loads the tray onto a metal container which simulates movement 24 hours. This process takes 2 minutes per watch. The watches are reexamined for time accuracy which takes another 45 seconds per watch and if they pass the test, they are sent for strap attachment. The empty trays are returned to the assembly line from the strap attachment department. How many trays should circulate between the assembly line and the strap attachment department if 1000 watches are to be examined during an 8-hour shift? The average processing time and waiting time is 2 days.
The value of the safety stock policy variable, a, is zero.