Integrated Optimization Modelling in Quality Control, Production Planning, Inventory Control and Maintenance

今天的工业主要集中在提高生产力和质量上。制造过程成功的关键是质量控制、生产计划、库存控制和维护策略的适当集成，直到最近，这些都被视为单独的问题。该研究提出了解决各种生产和质量控制问题的集成优化模型。本研究包括四组具有实践意义和理论意义以及训练价值的问题。***第一套涉及工艺参数和生产运行的联合经济选择。这个问题的产生是因为它会影响到客户产生的缺陷率、材料成本、报废或返工成本和质量损失。在生产过程中，工艺参数设置可能会进入失控状态。设定最佳工艺目标参数和确定最佳生产运行是许多工业过程的两个非常重要的因素。这些因素的有效整合将为制造商提供经济优势。预计本研究的结果将对最终用户非常有用。***第二组提出了一个不断恶化的生产系统的质量控制、生产控制和预防性维护的综合经济模型，在这种生产系统中，生产过程不仅可能从控制状态转向失控状态，而且可能在任何随机时间点发生故障。控制图的经济性设计是指为了选择质量成本最小的控制图参数而对成本模型进行优化。制造设备的预防性维护与制造产品的质量是相互关联的。提出的综合模型研究将在一般班次、故障和维修时间分布下进行。这项研究有望在该领域作出重大贡献。***第三组是针对不完美生产过程中库存物品劣化的动态集成模型，用于生产数量、检验调度和质量控制的联合优化。对于产品质量和生产数量同等重要的制造商，将提出一个用于库存、质量和维修问题的广义综合经济模型。***第四组是开发一个集成模型，用于确定随机寿命分布产品的最经济制造数量、最优保修成本、最优保修期限和最优价格。这是一个新的研究领域，它将分析库存、质量和维护的整合如何影响保修政策。它将显示，纠正维修政策将大大减少保修索赔。

Today's industry is mainly focused on improving productivity and quality. The key to success in manufacturing processes is the proper integration of quality control, production planning, inventory control, and maintenance policy, which have been treated as separate issues until recently. The proposed study presents integrated optimization modelling for solving various production and quality control problems. The research consists of four sets of problems which have practical and theoretical importance as well as training merit.***The first set involves the joint economic selection of process parameters and production run. This issue arises because it can affect the defect rate, material cost, scrap or rework cost and quality loss incurred by the customer. During the production period, the process parameters setting may shift to an out-of-control state. Setting the optimal process target parameter(s) and determining an optimal production run are two very important factors for many industrial processes. Effective integration of these factors will provide an economic advantage to the manufacturer. It is expected that the findings of this research will be very useful for end users.***The second set proposes integrated economic models for quality control, production control and preventative maintenance for a deteriorating production system in which the production process may not only shift from an in-control state to an out-of-control state, but also may break down at any random point in time. The economic design of control charts refers to the optimization of cost models for the purpose of selecting control chart parameters which minimize the cost of quality. The preventative maintenance of manufacturing equipment and the quality of a manufactured product are inter-related. The proposed research on integrated models will be formulated under general shift, breakdown and repair time distributions. This research is expected to make a significant contribution in the field.***The third set is the development of a dynamic integrated model for joint optimization of production quantity, inspection scheduling, and quality control for an imperfect production process with deteriorating inventory items. A generalized integrated economic model for inventory, quality, and maintenance problems will be presented for the manufacturer, for whom the product quality and the production quantity are equally important.***The fourth set is the development of an integrated model for determining the most economic manufacturing quantity, the optimal warranty cost, the optimal warranty period and the optimal price for a random lifetime distributed product. This is a new area of investigation which will analyze how integration of inventory, quality and maintenance can affect warranty policies. It will be shown that the corrective maintenance policy would considerably reduce warranty claims.