由厂外购进备件(包括协作件)或厂内组织生产,两条进货渠道都称为订货.外购或自制备件都需要一定的时间.订货周期多长,每次订货多少,都具有很强的经济性. 在企业中,可以把备件库看成是一个经济实体,订货费用、储存保管费用、缺件影响的损失费用以及超储所造成的浪费等,构成了一个备件费用锁链.如何使锁链最短,总费用最小,就是我们要讨论的问题. Purchase spare parts (including collaboration parts) from outside the factory or organize production within the factory. Both purchase channels are called orders. Outsourcing or self-manufacturing parts require a certain amount of time. How long is the order period? How many orders each time? Strong economy. In the enterprise, the spare part library can be regarded as an economic entity. The cost of ordering, storage and storage, the loss of missing parts, and the waste caused by overstocking constitute a chain of spare parts costs. Making the chain shortest and the total cost the smallest is the problem we are going to discuss.