SETUP REDUCTION AND MACHINE AVAILABILITY

This paper is an extension of Billington, who used the framework of the economic production quantity (EPQ) to model setup cost reduction. In the present paper, we use the EPQ model as a starting point to investigate the nature of setup costs and the effect of setup time reduction on the increase in available capacity. Reducing setup is vital to a company's success because a lengthy changeover of machinery is expensive: it demands long production runs to justify its cost, and these, in turn, lead to excessive inventory and to a slow response to customer needs. As in Billington, setup reduction is modeled as a function of an annual amortized investment. The paper examines the behavior of the setup time, the inventory cost, the lot size, and the freeing up of machine time in the face of a capacity constraint. A solution algorithm is provided to find setup times that minimize the sum of setup and holding cost, subject to a constraint on machine availability. The analysis sheds light on the true nature of setup cost and on the opportunity cost of not reducing setups. In the constrained optimization, the Lagrangian multiplier gives an estimate of the marginal value of adding one time unit of machine capacity, or, alternatively, of reducing one unit of setup time.     

论精益经营理念及其实践

精益经营(LeanOperation)理念是由日本丰田公司在20世纪70年代中期首先推行的,进而在80年代传到美国。JIT(just-in-time),即所谓零库存的物流管理,是精益经营理念的主要体现方式。本文对JIT的理论范畴从基本含义到实现条件,作了一定的阐述,从而引证了JIT理念在日本的实践所得到的三个基本点:消除浪费、全员涉入、不断提高。文章进一步列举了西方国家对JIT的成功实践,强调指出,提高经济效益重要渠道之一是减少成本,而减少成本必须消除浪费,JIT就是消除浪费的十分有效的方法。本文旨在倡导中国汽车行业应更好地借鉴精益经营理念和更广泛地应用JIT管理方式。     

论"管理会计"的发展

由于全球性竞争的日趋激烈,高新技术的迅猛发展,使得传统管理会计面临着挑战.针对传统管理会计存在的一些问题,提出了管理会计的发展前景是适应新世纪战略管理的需要,实现从传统管理会计向战略管理会计的转变.     

JIT生产方式在中餐企业中的应用分析

JIT生产方式作为企业提高市场竞争力的有力手段正在被越来越广泛地认识、研究和应用,而目前JIT生产方式的应用主要是针对制造业。文中主要分析了起源于制造业的JIT生产方式被应用于中餐企业是如何提高其服务质量和管理水平,首先对JIT生产方式在中餐企业的适用性进行分析,然后将其生产流程的三个环节拆解,分别指出其中存在的问题,利用JIT的相关理论来依次解决其发展中的问题,最后提出中餐企业在引入JIT时的建议。     

生鲜物流JIT配送效益分析

从生鲜农产品种养收获到零售环节中,配送环节对生鲜经营效益影响较大。文章对生鲜物流JIT配送所获得的整体效益进行了定性、定量分析,并与传统配送方式进行对比,表明了针对生鲜物流,JIT配送获得的效益比传统配送获得的效益大。     

面向JIT制造的零部件配送中心货位优化研究

面向JIT生产的零部件配送具有种类多、批次多、批量少、出入库时间分散等特点,使得有效分配配送中心的存储货位成为一个难题.将存储货位分配问题抽象为三角形装箱问题,构建了考虑时间维度的货位分配模型,设计了求解该问题的启发式算法.应用某知名汽车装配企业零部件配送中心的实际数据,对货位分配优化模型及算法进行了验证,实证数据表明模型及算法能够有效降低运营成本,提高存储空间利用率.     

准时制(JIT)采购的战略价值及实施

本文通过和传统的采购方式的比较,分析了准时制（JIT）采购的战略价值,进而提出如何根据我国的实际情况实施JIT采购,从而提高企业参与全球化竞争的能力。     

Production control for just-in-time tool-and-die manufacturing

The strategy to implement production control varies in different types of manufacturing systems. We address the issue of production control in unit-based manufacturing systems where the production batch size of the final product is one or two, the product is custom designed and is made up of numerous individual components with similar process routeings lor special machine tools, turbines, boilers, tool-and-die, injection moulding equipment, custom fabrication, etc. We have developed algorithms to generate master production schedules in this particular domain of manufacturing systems using the concept of workgroups. We show how a Kanban-based JIT shopfloor control and purchasing system can be implemented in such systems in tandem with an inventory management system by utilizing the concept of demand lists. We also propose a model for practical implementation of production control in this domain. The methodology is illustrated at a tool-and-die plant where a CIM software is used to apply the JIT-based production control. Preliminary results show a significant reduction in lead times. We try to show the relationship between research and industrial applications of productions of production control and how to bridge the gap between them.     

Experimental push/pull production planning and control system

We introduce an experimental push/ pull production planning and control software system which is designed as an alternative to a MRP-II system for mass manufacturing enterprises in China. It has the following distinguishing features: (1) putting the philosophy of JIT into the master production scheduling of MRP-II via the earliness/ tardiness production planning method; (2) controlling material input by push and processing/ assembly by pull; and (3) adjusting the parameters of the production line by the‘ suggestion for improvement of production line’ module. Simulation results have shown that the proposed system can achieve better planning and control performance than existing systems.     

THE EMPIRICAL DETERMINANTS OF INVENTORY LEVELS IN HIGH-VOLUME MANUFACTURING

This study uses survey data on several hundred automotive suppliers in North America to evaluate the determinants of inventory levels in high-volume discrete parts manufacturing. We assess the magnitude of raw materials, work-in-process, and finished goods inventories held at automotive supply plants. Inventories are shown to be jointly determined by technological and managerial factors in a manner roughly consistent with classical inventory theory. Several categories of managerial practices are found to be important. Low inventories are linked to employee problem solving and frequent communication with customers. More unexpectedly, we find the absence of inventory differences between U.S.-owned and Japanese-owned plants in North America. This contrasts with substantial differences in inventory holding between US plants and those in Japan.