A demand-pull system, just-in-time (JIT) manufacturing strives to produce a product only when it is needed and only in the quantities demand by customers. Demand, measured by customer orders, pulls products through the manufacturing process. Each operation produces only what is necessary to satisfy the demand of the succeeding operation. No production takes place until a signal from a succeeding process indicates the need to produce. Parts and materials arrive just in time to be used in production.