In terms of the purchase of intermediate products in the market, because a lot of manufacturers are generally buy goods from a handful of suppliers, it is beneficial to this a few suppliers to achieve economies of scale and reduce the cost of production. Moreover, market competition pressure between intermediate product suppliers forces suppliers to reduce production costs. In addition, when a few suppliers in the face of many intermediate products of demanders, these a few suppliers can be avoided due to the limited market demand caused by unstable, the loss that may lead to maintain a stable overall sales. Whether the method of loading is finite or infinite, when work arrives, decisions should be taken on an order when the work will likely be tackled. This activity is termed sequencing. The priorities given to work in surgery in many cases are dependant on some predefined pair of rules, a few of which are relatively complex.