制造流程分层次规划方法的研究与应用

结合汽车齿轮制造企业在生产过程中物流的"均衡性"问题,研究了产品制造流程分层次规划方法.提出了将制造流程分析过程系统划分为生产系统层、生产线层、制造单元层进行分析的观点,系统研究了该类方法的理论体系框架及其与优化方法、计算机仿真方法、工业工程方法3类方法集成的实现过程,结合企业的制造过程分析了改善的应用效果.     

基于Flexsim的炼镁生产线仿真与优化

对山西某镁业有限公司的炼镁生产线进行了现场调查,明确了该生产线炼镁流程,收集了大量数据,统计出工序分布.建立了炼镁生产线的Flexsim仿真分析模型,确定了现行流程的瓶颈环节位于合成和(或)还原工序.对此,提出了增加1个合成车间、1个还原车间和2个还原车间的3种流程改进方案,并分别进行了仿真分析.结果表明引起堵塞的真正原因不是合成能力不足,而是还原能力不足.而在现行流程中增加2个还原车间,就可以彻底解决原系统的堵塞问题,而且效率可以提高1.98倍.     

基于 Witness 轿车焊装车间焊接生产线的仿真与优化研究

通过对某汽车焊接生产线工艺流程的研究,运用 Witness 仿真软件建立层次清晰的系统仿真模型。 根据仿真目标,设计了 2 组仿真试验,依据仿真结果进行焊接生产线的瓶颈分析、设备利用率分析以及设备产能匹配分析,为生产调度计划的制定、生产线的规划与布局提供科学的依据。     

生产线平衡与企业利润关系的研究

在对制造型企业生产线平衡问题进行分析的基础之上,结合生产线实际,利用仿真的方法对电子制造企业进行了研究,通过不断提高生产线的平衡率来揭示平衡率与企业利润之间的关系.仿真结果显示,提高生产线平衡率并不总是能够提高企业的生产效益,并由此针对生产线的持续改善提出了具体方法与实施步骤.     

基于Witness的某制造车间生产线仿真优化

以某立柱制造车间生产线设计为例,运用TOC约束理论和DBR排程理论,结合Witness软件进行制造系统的建模与仿真,分析影响制造系统生产线的各种影响因素,通过设置各项参数、调整设备数量来优化生产物流,提高机器利用率和生产效率以使企业在市场竞争中获得优势。     

生产系统的集成规划及案例分析

在分析以往制造系统设计存在不足的基础之上,论述面向生产工程的虚拟制造内涵、提出了虚拟制造环境下大批量生产的制造系统集成规划的解决方案,它包括系统布局规划、仿真规划和虚拟漫游规划3个阶段,各个阶段解决系统规划的不同优化问题,并以来自企业的应用案例进行分析,为企业设计优化的生产系统,减少投资风险。     

基于虚拟仿真技术的灌装生产线设计与仿真

目的 针对灌装生产线的设计与验证过程,基于虚拟仿真技术,实现灌装生产线的快速设计与验证。方法 首先通过分析灌装生产线的生产过程,利用SolidWorks三维建模软件分别对灌装生产线中的灌装机、搓盖机、贴标机、喷码机、装箱机等设备设计三维模型。然后将所有设备的三维模型导入Demo 3D仿真软件,进一步按照各设备的动作流程对模型进行动作设计及运动规划,构建灌装生产线虚拟仿真系统。最后根据设备功能和生产产能要求,在虚拟仿真系统中通过不断地调整设备机械结构及机构的运行速度,最终实现灌装生产线的快速设计与迭代优化。结果 得出灌装生产线的优化设计方案,并根据该设计方案研制出灌装自动生产线,生产线的产能为2400 瓶/h,满足企业要求。结论 该方法能够实现灌装生产线的快速设计与验证,缩短设计开发周期,减少设计和验证成本。     

基于价值流图的齿轮生产线分析与改善

以某齿轮生产线为研究对象,在分析生产流程的基础上,根据现场采集数据绘制了价值流现状图.结合工业工程和精益生产的基本方法,以拉式生产建立连续流程,重新布置生产线,并绘制了未来状态图,为企业拟定了未来改善方案.该方案的实施能为企业带来良好的经济效益,并为齿轮制造行业提供一定的借鉴.     

可重构制造系统的布局规划技术研究

分析了可重构制造系统的内涵,提出了制造系统重构的三种分类(逻辑型RMS、改进型RMS和创新型RMS)并给出了制造系统重构的流程.在利用UML对制造系统建模的基础上,建立了统一的面向改进型RMS和创新型RMS布局规划的多目标规划数学模型.提出了启发式算法和遗传算法相结合的混合遗传算法,解决了创新型RMS布局规划问题.实例验证了算法的可行性和有效性.     

生产线的虚拟集成设计

作为制造系统设计的重要组成部分,生产线的设计与生产线设备的利用率、产品的生产时间和生产线的效率等密切相关。传统的生产线的设计过多地依靠经验和手工演算,缺少科学性。本文利用贯穿虚拟制造的关键技术－不同层次的仿真,提出了生产线系统的虚拟设计集成架构,列出了在此架构的指导下的主要设计内容,介绍了国内外相应软件的情况,最后,给出了生产线三维动画虚拟设计的一个实例。     

模块化生产在复杂系统制造过程的运用研究

基于复杂系统制造过程对完善生产资料准备、缩短制造周期、增强生产计划控制力、提升高端制造业发展水平的迫切要求,根据模块化理论、制造工艺、项目管理、最优化理论等方法,构建复杂系统制造模块顺序网络图,并建立求解制造周期的整数规划模型,最后举出实例,运用优化求解软件CPLEX得出整个系统制造周期及对应的关键制造路径,运用求解结果制定生产资料准备计划及生产计划,发现模块化技术实行后,生产计划及生产资料准备计划实现最大并行化开展,且生产资料准备先于生产计划开展前完成,整个系统制造周期大大缩短,验证了模型的有效性、准确性和优越性。     

制造业车间作业计划与调度研究

基于车间作业计划( Production Activity Control,PAC)是企业生产计划的最终环节,且其对制造领域里的经营管理效率起着支撑作用,因此针对当前企业存在的诸多问题,在系统分析了作业的特点以及对PAC编制的来源及过程的总结基础上,科学地归纳出制造业领域的车间作业计划(PAC)与调度流程,并给出了相应...     

基于Plant Simulation的智能制造测试床仿真模型 设计与应用

为了验证智能制造测试床的整体布局设计和制造工艺在生产运营环境下的合理性，利用西门子Plant Simulation工厂仿真软件进行生产节拍和设备利用率分析。首先，建立了按订单生产运行的制造生产线二维仿真模型，根据生产要求对二维仿真模型进行输入参数设定，并根据二维仿真模型运行后得到的分析统计结果进行工艺布局、物流布局和制造策略的优化。然后，在二维仿真模型基础上，为了让仿真模型在建设阶段和运营阶段具有更直观的展示效果，基于原三维设计图，在三维仿真模型中替换或导入各对象的三维模型，并运用Simltalk语言编写精细的三维位置坐标和动作路径动画程序，对仿真模型进行三维效果优化。结果表明优化后的智能制造测试床三维仿真模型可以实现与实际生产一致的业务运行模式，它具有更形象、逼真的动态运行展示效果。仿真结果可指导智能制造测试床的建设与优化，且在测试床投入运营后，仿真模型还能够接受运营数据以对测试床进行持续迭代的优化。提出的仿真模型设计方法为实现智能制造测试床的“数字孪生”奠定了基础。     

A quantitative approach for measuring process innovation: a case study in a manufacturing company

Process management and innovation arguably remain among the concepts under focus of recent researches since there is no significantly outstanding method to measure and monitor the level of innovation in the manufacturing processes over a particular time period taking the fundamental activities of manufacturing processes into account. Although there are various studies relevant to process improvement, manufacturing processes are not focused on in the literature. This paper presents a novel performance indicator, called degree of process innovation, for monitoring and measuring innovation in manufacturing processes based on the four most important components among the fundamental activities of a manufacturing system. The components are namely Average Labour Utilisation, Cumulative Bottleneck Ratio, Unit Production Time and Unit Production Cost. The idea behind this approach has flourished on the basis of an indicator proposed in the literature to measure the general organisational improvements. The scope of that indicator has been narrowed down to manufacturing processes to accurately reflect the state of the manufacturing processes. The proposed approach has been verified with a case study in manufacturing industry, where each of the four sub-indicators was calculated based on the data provided and aggregated into the degree of process innovation. The innovation degree is successfully indicated.     

Strength Analysis and Process Simulation of Subway Contact Rail Support Bracket of Composite Materials

An application of composites for construction of subway brackets is a very effective approach to extend their lifetime. However, this approach involves the necessity to prevent process-induced distortions of the bracket due to thermal deformation and chemical shrinkage. At present study, a process simulation has been carried out to support the design of the production tooling. The simulation was based on the application of viscoelastic model for the resin. Simulation results were verified by comparison with results of manufacturing experiments. To optimize the bracket structure the strength analysis was carried out as well.     

A review of production control problems in cellular manufacture

Several benefits have been claimed from the introduction of cellular manufacture. One of these benefits is simplified Production Control. A general consensus of opinion, by exponents and users alike, is that a detailed, well defined production control system must be designed if benefits are to accrue from cellular manufacture.

The performance of a manufacturing system is dependent upon many criteria and it has its own rules, conditions and limitations. Production control system in cellular manufacture is no exception. This paper attempts to define some important Production Control problems and identifies various factors and features which influence effective control of cell production.

The design of a production control system within cellular manufacture is quite complex. It requires a good definition of component families to set up a balanced manufacturing cell in terms of numbers of machines and men to give optimum utilization and efficiency. The layout of the cell should be such that the flow of material can be maintained through the machines to optimize work-in-progress levels and minimize queueing problems. Sequence Technology, coupled with reduced batch size and Period Batch control, appears to achieve the desired level of throughput and maintain optimum work-in-progress in a cell. However, optimum schedules will vary according to the weight given to different criteria and savings. Several simulation studies have been carried out to understand the relative effects of such criteria and simple analysis can be used to make decisions in finding a viable and near optimum solution.     

Joint production and quality control of unreliable batch manufacturing systems with rectifying inspection

Production control policy and economic sampling plan design problems have been studied separately in previous research. This paper considers a joint production control policy and economic single sampling plan design for an unreliable batch manufacturing system. The production is controlled by a modified hedging point policy which consists of building and maintaining a safety stock of finished product to avoid shortages during corrective maintenance. The main objective of this paper is to determine simultaneously the economic production quantity, the optimal safety stock level and the economic sampling plan design which minimise the expected overall cost. A stochastic mathematical model is developed and solved using a simulation optimisation approach based on the response surface methodology. Simulation is used to imitate the complex dynamic and stochastic behaviour of processes as in the real-life industrial systems. The obtained results show clearly strong interactions between production quantity, inventory state and sampling plan design which confirm the necessity of jointly considering production and quality control parameters in an integrated model. Moreover, it is shown a significant impact of production system reliability on the economic sampling plan design and therefore on the quality of finished product delivered to consumers. Numerical example and sensitivity analyses are presented for illustrative purposes.     

Productivity Modeling of Group Machine Loading with Variable Processing Times

This paper describes a procedure for optimizing the Tota Productivity (TP) in a manufacturing process under a Group Technology production environment. This is achieved by inputting the optimal values of the cutting parameters (such as speed, feed, and depth of cut under different manufacturing process conditions) into a fractional programming model, which will then compute the optimal total productivity values for such cutting parameter values.

The application of this procedure offers greater flexibility to take advantage of the Group Technology concept by allowing management to consider optimal combinations of cutting parameters for the optimum use of resources.     

DOPP—dynamically optimized production planning†

Production planning in flexible manufacturing requires the updating of work schedules each time a new product order is acquired. To this end, a Production Planning (PP) strategy should be devised by solving two coupled problems, embedded into an iteration: (i) Product Orders Scheduling, (ii) Production Capacity Planning. This paper presents a new algorithm to solve the Production Capacity Planning (PCP) Problem for a complex manufacturing system composed of a network of bufferized time-sharing workshops (i.e. shops able to share their service rates among different part types). The solution procedure developed allows one to minimize the Global Flow Time (GFT), while verifying service and storage capacity constraints, in association with a given future pattern of product orders. An example derived from an existing production process is outlined, to show the effective usefulness of the proposed PCP procedure, and its easy integration with existing scheduling tools     

Nested coloured timed Petri nets for production configuration of product families

Production configuration is as an effective technique to deal with product variety while maintaining production stability and efficiency. It involves a diverse set of process elements (e.g., machines, operations), a high variety of component parts and assemblies and many constraints arising from product and process variety. Production configuration entails the selection and subsequent arrangement of process elements into complete production processes and the final evaluation of configured multiple alternatives. To better understand production configuration and its implementation, we study the underlying logic for configuring production processes using a dynamic modelling and visualisation approach. This is accomplished by developing a new formalism of nested coloured timed Petri nets (PNs). In view of the inherent modelling difficulties, in the formalism three types of nets–process nets, assembly nets and manufacturing nets–together with a nested net system are defined. Using an industrial example of vibration motors, we show how the proposed formalism can be applied to specify production processes at different levels of abstraction to achieve production configuration.