多产品生产计划与非周期预防维修整合优化模型

Joint Optimal Multi-product Production and Non-cyclical Preventive Maintenance Planning Model

本文将离散制造业生产计划问题与生产设备的非周期预防性维修相结合进行研究,在有限的生产计划期中包含若干个等长度的时段,各个时段中都有需要被满足的多种类的产品需求量,并将每个时段的末期作为可选的预防性维修窗口,利用实际的设备运行时间计算设备维修对生产能力的占用。计划期内生产和维修的费用包括:生产费用、库存费用、延期交货费用、设备调整费用和设备维修费用,以最小化这些费用的总和为目标建立整合模型并进行优化,确定最优的生产计划及设备预防性维修序列。并运用数值案例对所建立的模型进行应用分析。

The production and maintenance activities share the same system in reality,so the conflict is inevitably generated.If the arrangement of the production plan and the maintenance schedule are not reasonable,the shortage of the products and the improper maintenance(inadequate maintenance or excessive maintenance)may occur.To avoid this negative influence,the integrated model of the production planning problem of discrete manufacturing industry and non-cyclical preventive maintenance is proposed in this paper.The finite production planning horizon is composed of several equal-length periods.in each period,the demands of multi product should be satisfied by the production quantity in this period and the inventoryof last period,otherwise,the backorder will happen.The non-cyclical preventive maintenance can be carried out at the end of some production periods,and the minor repair is used to deal with system failures.The occupation of production capacity is composed of maintenance and system setup.In each period,the time can be used to product is equal to the length of the period minus the maintenance and setup time,and the actual running time of system is used to formulate the failure numbers.Furthermore,the maintenance time of failure can be presented.Then′the integrated production and maintenance model is developed in the form of mathematical programming.The objective of the model is to determining the optimal production panning and preventive maintenance sequence that minimizes the sum of the production cost,inventory cost,setup cost and maintenance cost.Based on the production data of steel grating gathered from a steel facility,a case study is presented to illustrate the integrated model,the optimal production plan and the optimal maintenance schedule are determined simultaneously.Moreover the result shows that the optimal maintenance schedule is not cyclical,since the non-cyclical maintenance policy presents more maintenance sequences than that presented by cyclical maintenance policy.