基于FLEXSIM的某生产线物流仿真优化

通过收集某企业挖掘机装配流水线的工艺路线、工序设备处理率、生产节拍和生产线平衡等方面数据,利用FLEXSIM物流仿真软件构建装配流水线仿真模型,比较装配流水线优化前后指标,发现优化后的装配线具有生产节拍时间缩短、瓶颈工序缓解、生产线产能平衡等优点。     

基于FLEXSIM的某生产线物流仿真优化

通过收集某企业挖掘机装配流水线的工艺路线、工序设备处理率、生产节拍和生产线平衡等方面数据,利用FLEXSIM物流仿真软件构建装配流水线仿真模型,比较装配流水线优化前后指标,发现优化后的装配线具有生产节拍时间缩短、瓶颈工序缓解、生产线产能平衡等优点.     

如何确定生产节拍

通过生产节拍的控制,可以平衡生产中各种资源运动的量与速度、识别并解决生产中的瓶颈问题。在"一个流"、平准化生产中,生产节拍(TakeTime)起着控制生产工序的加工时间,消除设备利用率低、生产线严重阻塞等现象的作用。生产线节拍平衡是现代生产管理的关键,因为流线化生产中任何一个问题都会在整个生产线和供应链上放大,从某种意义来说,将比传统大量生产方式造成更大程度上的浪费。     

一种新的汽车玻璃生产线在制品库存控制的多项式算法

汽车玻璃加工生产线需要加工不同类型的玻璃。这样,汽车玻璃预处理生产线需经常从加工一种类型的玻璃切换到加工另一种类型的玻璃。由于其切换时间较长,为了保证其下游工序可连续生产,往往需预留大量库存。为了减少库存,本文分析了汽车玻璃生产线的运行过程,并提出了新的多项式算法调度汽车玻璃预处理生产线。证明了通过该算法调度预处理生产线,使得预处理生产线的后续工序可连续生产,得到所需最小的预处理生产和压弯成型工序平均中间库存。最后,实例验证了本文提出的方法的有效性。     

冷轧生产物流失衡分析和临界值计算

介绍了钢铁企业冷轧生产物流的运营状况及物流失衡原因,讨论了冷轧各工序生产线之间的能力平衡约束、设备故障约束和在制品库存约束等瓶颈问题,并深入探讨了冷轧生产物流失衡的临界值及相应的研究意义。     

企业生产物流系统的建模与仿真

采用Petri网建立了某微型汽车厂总装车间的生产物流模型,并用VisualBasic语言对其生产线进行仿真。从而发现在生产不同的车型时,总装车间的三条流水线的节拍不一致,在生产空调车时,为了满足生产的平衡性,不仅要细化超工位装配的工序,而且需要对车间的人员安排进行调整。     

基于遗传算法对A公司生产线平衡的分析

在对A公司总装车间底盘装配生产线平衡现状进行分析的基础上,应用遗传算法对A公司总装车间底盘装配生产线进行分析改善,使得A公司总装车间底盘生产线瓶颈工序时间得到了有效地降低,生产线平衡率从76.3%提高到95.1%,生产线平衡损失率由原来的23.7%降低到4.9%,提高了生产线的平衡性。     

基于遗传算法对A公司生产线平衡的分析

在对A公司总装车间底盘装配生产线平衡现状进行分析的基础上,应用遗传算法对A公司总装车间底盘装配生产线进行分析改善,使得A公司总装车间底盘生产线瓶颈工序时间得到了有效地降低,生产线平衡率从76.3%提高到95.1%,生产线平衡损失率由原来的23.7%降低到4.9%,提高了生产线的平衡性。     

基于IE方法的某公司生产效率改善

以B公司的发动机装配线为研究对象,通过记录生产现场每道工序操作员的工作时间,与节拍时间进行对比分析,提出发动机装配线存在的问题。同时运用5W1H提问技术和ECRS原则、程序分析图、联合操作分析图等方法对瓶颈工序以及问题工序提出改善建议,令每道工序操作时间达到生产节拍之内,使装配线相比之前更加平衡,效率得到提高。     

工业工程对制造业工作效率的影响分析

工业工程对我国制造业的发展有着深远的影响,但今传统制造业的流水生产线存在着平衡率低下的问题,这成为阻碍其发展的因素。通过提高操作员以及机器设备的工作效率,进而提高生产线平衡,提高人均产量以及生产应变能力,从而满足客户的需求,提交出高质量,低成本的产品。本文介绍了我国工业工程在企业中的现状,接着以YQ公司激光笔流水生产线为研究对象,运用工业工程思想,根据其原先由的各个工序的标准时间并计算出节拍和平衡率,接着确定瓶颈工序以及其他的问题工序。通过运用方法研究、程序分析、ECRS等工业工程方法对问题工序进行优化改善,提高企业的生产力、竞争力,降低成本。     

流水型CONWIP生产系统研究

本文研究了流水型CONWIP生产系统中在制品常量、批量和加工次序的问题。以机床加工准备成本及工件库存成本和加工流动时间为优化目标．建立了CONWIP系统整数规划模型，并提出了求解问题的启发式算法。在优化机床准备及库存成本的基础上．得到各产品的生产批量和系统在制品常量。同时，提出了流水型CONWIP生产系统的排序算法（CFA），依此得到产品的较优加工次序。本研究使CONWIP模型求解得到简化且易于应用，并获得满意解。     

流程程序分析在注塑企业的应用

文章运用流程程序分析方法对电动工具箱的生产流程和设备布局进行了分析,对生产流程程序和设备布局提出了再造方案。新方案的实施缩短了生产周期、减少搬运浪费和操作人员、降低了在制品库存。     

考虑工人行为激励的装配线产出率的实验研究

传统IE模型均基于在制品库存与工人行为互相独立的假设。近来一些学者提出低在制品库存能给工人带来正激励作用。但在对我国一些产品组装类型的民营企业调研中发现,相比低在制品库存装配线,高在制品库存装配线对工人的激励效应更为显著。本文对高在制品库存装配线产生的激励效应提出多个假设,并通过装配线的模拟实验进行了验证,最后进一步研究分析了结论所适用的企业类型。     

生产物流平衡的持续优化在硬盘磁头制造业的应用

以广东某硬盘磁头代工企业生产线为研究对象，运用装配线平整技术，以生产物流平衡为目标分析了设备能力、任务分配、工装改善以及生产计划排配等方面存在的问题：提出并实施了改善方棠。保证了生产线的物流负荷平衡。优化方案的实施使企业生产能力提高并有效地降低了生产线在制堆积的问题，在制品周转从3．2天缩短到2．5天，生产现场的环境也得到了改善。     

Integer goal programming for multistage lot sizing: Experimentation and implementation

This article considers the issues involved in implementing a large-scale multistage lot sizing model in a pharmaceutical manufacturing environment, and reports on a series of sensitivity experiments that subsequently examined the critical impacts of system capacity and inventory policy on the specification of a multistage schedule. The model was initially developed as an aggregate scheduling aid for a class of tablet pharmaceuticals. The manufacture of tablet products is a serial-type process characterized by batch flow. The model placed multiple resource capacity restrictions on various stages of the multistage system to ensure the feasibility of the resultant schedules. Difficulties in estimating penalty costs for shortages were circumvented by employing a multi-objective formulation of the lot-sizing problem.Various obstacles encountered during the implementation process are discussed. Model implementation encompassed the development of an approximation algorithm for efficiently solving the large-scale problem. The performance of the algorithm was evaluated by examining the closeness to optimality of the solutions obtained using the procedure. Performance statistics are presented for the sensitivity experiments discussed herein. Another essential aspect of implementation involved the timely revision of model input parameters. This facet of implementation proved to be at least as important to management as the efficient provision of a “good” solution.Model experimentation centered on variations in the capacities of bottleneck resources and changes in target inventory parameters whose values are predetermined by company policy. The first set of experiments was designed to demonstrate the importance of system capacity to the lot-sizing process and to illustrate that the location of a system bottleneck can vary over time as a function of both internal and external factors. The results indicated that lot-sizing procedures that fail to incorporate capacity information or that focus on a single bottleneck production stage in order to schedule production are severely limited with respect to practical and/or long-term applicability.The final set of inventory-related experiments indicated that the specification of target ending inventory levels was a crucial factor in the lot-sizing process. The determination of appropriate target levels must reflect the inherent trade-off between the objective of minimizing shortages and the desire to avoid excessive inventory accumulations. The generation of usable model information was found to be contingent upon the realistic definition of target level parameters.     

Manufacturing lead time accuracy

This article addresses the question of accuracy of planned lead times (PLTs) that are used with a material requirements planning system. Lead time error is defined as the difference between an item's PLT and the actual lead time (flow time) of an order to replenish the item. Three related topics are discussed: the relationship between system performance and average lead time error, the transient effect on work-in-process (WIP) inventory of increasing PLTs, and the relative accuracy of three methods of determining PLTs. A distinction is made between available and WIP inventory. The former includes any purchased item, fabricated part, assembly, or finished good that is in storage and available for use or delivery. WIP denotes materials associated with open orders on the shop floor.It was concluded that average lead time error has a considerable affect on system performance. PLTs that are on average too long or too short increase available inventory; and the further the average error is from zero, the more pronounced the increase. Contrary to conventional wisdom, increasing PLTs will increase the service level (decrease backorders), unless PLTs are already severely inflated and MPS uncertainty (forecast error) is small. If PLTs are inflated, decreasing them will decrease the number of setups per unit time in the case of considerable demand uncertainty. Contrary to conventional wisdom, increasing PLTs causes only a transient rise WIP inventory.The fact that the average lead time error has a significant effect on the three areas of system effectiveness mentioned above does not imply that a given order's lead time should be managed in a way that forces its actual lead time to match the PLT. Stated another way, the material planner may use the latest information to manage a given order's lead time; however, if the average discrepancy between the actual and planned lead times is large, system performance can be improved by changing the PLTs to approximate the average flow times.Three methods that have been proposed for determining PLTs are compared. They are historical averages of the actual flow times, calculated lead times based on standard times and historical averages of the queuing time at the appropriate work centers, and the QUOAT lead time proposed by Hoyt. The third was found to perform poorly unless the work content of all operations is identical. With one exception, no differences were found between the first two methods. The simpler historical average method was superior to the calculated lead time in the case where the work content of each operation varies and when considerable demand uncertainty exists.The results are based on simulation experiments employing a generalized MRP/Job-Shop stochastic simulation model. The program launches orders based on standard MRP logic, reschedules open orders by moving the due date in or out to coincide with revised need dates, moves manufacturing orders through a job shop, schedules the delivery of purchase orders, and updates inventory levels. The product structure tree contained eight distinct items, with four levels and one end item. There is no reason to believe that the conclusions would be any different had a larger system been studied.     

基于联合库存管理的供应链系统动力学研究

介绍了联合库存供应链管理与一般库存供应链管理之间的差别，以系统动力学为工具，建立了基于联合库存管理策略的供应链动态仿真模型，对供应链过程中的关键影响参数进行了定量分析，研究了瓶颈环节和牛鞭效应对整个供应链的影响。     

An analysis of process industry production and inventory management systems

The process industries — those firms that add value by mixing, separating, forming and/or chemical reactions by either batch or continuous mode — continue to lag behind the discrete industries in the identification and implementation of effective production and inventory management (P&IM) techniques. A contributing factor is that the process industries have traditionally been lumped together and contrasted from the discrete industries as a whole, thus leading to misunderstandings regarding individual process industries. From site interviews and the literature, we identified four critical dimensions — planning resource requirements (for materials and capacity), tracking resource consumption, control of work-in-process (WIP), and degree of computerization — represented by seven variables by which to contrast and analyze process industries. Based on in-depth field studies of 19 diverse process plants, we find that there exist at least four distinct types of process industry P&IM systems: (1) simple, (2) common, (3) WIP-controlled, and (4) computerized.     

基于TOC的煤炭企业库存控制研究

在分析库存控制相关理论的基础上,对当前煤炭企业库存现状进行了分析,提出了库存产生的原因,并对煤炭企业库存的影响因素进行了分析。接着,从煤炭企业库存存在的问题出发,利用约束理论找出影响当前煤炭企业库存的瓶颈,针对问题的根源,制定了解决问题的方案。