Raissa's Teapot Firm Is Moving to a JIT System

Short Answer

Raissa's teapot firm is moving to a JIT system. One question they are trying to answer is what level of safety stock they should maintain. They produce 240 teapots every four hours. The teapot ceramic handle vendor will deliver a container containing 30 parts one hour after they receive a request to ship. Raissa's kanban system uses four containers. What should they maintain as a safety stock?