The study on inventory control is mainly about routine purchase,but urgent purchase often takes place.

Aiming at the rush order inserting problem in a make-to-order manufacturing system adopting Load Oriented Manufacturing Control(LOMC) and LOMC-based Due Date Assignment(LDDA) technique,an order inserting method called "order rearrangement" was proposed.

Because of the intense competition in the market of semi-conductor day by day,it is quite difficult to master and control the demands from customers,which elevates the frequency of rush orders.

Under the preconditions that the periodic check-up is taken as inventory strategy at all nodes in the system,replenishment is to be done at fixed intervals,lead time is comparatively shorter than replenishment interval and emergency replenishment from upstream supplier(s) is available when stock-out happens,the ETC(expected total cost) models are developed in either case,i.