Discrete manufacturing is the production of distinct items. Automobiles, furniture, toys, smartphones, and airplanes are examples of discrete manufacturing products. The resulting products are easily identifiable and differ greatly from process manufacturing where the products are undifferentiated, for example oil, natural gas and salt. Discrete manufacturing is often characterized by individual or separate unit production. Units can be produced in low volume with very high complexity or high volumes of low complexity. Low volume/high complexity production results in the need for an extremely flexible manufacturing system that can improve quality and time-to-market speed while cutting costs. High volume/low complexity production puts high premiums on inventory controls, lead times and reducing or limiting materials costs and waste.