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.     

基于价值流的汽车座椅滑轨生产线分析与改善

以华瑞汽车座椅滑轨生产线为例,论述了应用价值流图技术进行生产现场系统改善的过程.首先根据该厂生产线现状和价值流图的符号,以可视化的方式描述生产线的现状,然后结合工业工程的基本分析方法,找出了该厂生产线中所存在的设施布置、搬运、等待、设备不足等制约产能的瓶颈问题,区分了生产中的增值和非增值的环节.最后寻找消除这些浪费环节的方法,对生产线按精益原则布置,绘制出了未来状态图,帮助管理者准确地拟定未来的改善方案.通过生产过程的实施带来产能和经济效益显著变化.     

基于仿真技术的民航地面服务过程精益改善分析

为缩短民航旅客在地面服务过程中的办理时间,本文提出将仿真技术与价值流图析(VSM/A)技术相结合的方法应用于机场地面服务过程的精益分析与评价,以预测精益改善的动态效果。以首都机场某航站楼为例,建立了旅客登机过程和安检过程价值流现状图,提出了民航服务过程精益改善的原则,详细分析了安检过程精益改善的主要措施,在验证仿真模型有效性的基础上,计算得到安检区域价值流未来状态图中的各时间数据,仿真结果表明,精益改善后可以明显缩短旅客在流程中的总持续时间和等待时间。     

基于价值流视域下的AIP公司生产流程改善研究(上)

以提高企业运作效率为核心,选取AIP公司轮胎生产线的优化作为本次研究案例,首先,通过绘制现状价值流图,达到生产线的现状可视化,分析工艺布局与物流和信息流的活动,找出当前生产模式中存在的增值与非增值环节;其次,运用精益思想和工业工程的方法,对生产流程进行分析与改善,引入看板拉动式和连续式生产等方法,以节拍平衡方式进行生产,压缩非增值时间、消除信息阻碍、减少作业人员和在制品库存等,使生产周期及产能得到有效改善;再次,采取工序重组、流程优化等改善手法,对生产流程进行精简,并绘制未来价值流图作为重点改善方向,从而实现生产线的再设计;最后,通过价值流图的前后对比发现:企业产能、设备利用率及生产周期改善显著,在提高产品质量的同时有效地降低了生产成本。     

基于EVSM及仿真技术的精益生产改善研究

构建了环境价值流图分析法,使价值流图分析涵盖了环境因素,弥补了传统价值流图分析的不足。同时,将环境价值流图分析与仿真技术结合,提高了未来价值流图绘制的客观性。以某电机厂定、转子的生产过程为例,应用环境价值流图从时间和能量消耗2个方面,识别了该厂生产过程存在的问题,以时间及能耗增值率为改善主线,利用工业工程手法与Flexsim仿真等方法进行改善,减少了在制品数,提高了该厂生产过程中的时间增值率。同时,改善了生产过程中的能耗增值率,降低了生产过程对环境的影响。     

基于价值流视域下的AIP公司生产流程改善研究(下)

本文以提高企业运作效率为核心,选取AIP公司轮胎生产线的优化作为本次研究案例:首先,通过绘制现状价值流图,达到生产线的现状可视化,分析工艺布局与物流和信息流的活动,找出当前生产模式中存在的增值与非增值环节;其次,运用精益思想和工业工程的方法,对生产流程进行分析与改善,引入看板拉动式和连续式生产等方法,以节拍平衡方式进行生产,压缩非增值时间、消除信息阻碍、减少作业人员和在制品库存等,使生产周期及产能得到有效改善;再次,采取工序重组、流程优化等改善手法,对生产流程进行精简,并绘制未来价值流图作为重点改善方向,从而实现生产线的再设计;最后,通过价值流图的前后对比发现:企业产能、设备利用率及生产周期改善显著,在提高产品质量的同时有效地降低了生产成本。     

基于工序分析方法的企业生产流程优化研究

运用工序分析方法对GL公司核心产品的加工平面布局和生产流程进行优化和再设计,分析加工车间布局的现状图,构建其优化图,优化设计生产流程。提出通过调整工序顺序、优化平面布局、加强作业人员规范操作培训等措施,来消除制造过程中的信息阻塞,使得工序总数减少了7个,搬运的距离缩减了74.9m,作业人员减少了5人,停滞的时间减少了138min,日产能提升108件。实践结果表明:在企业产品制造流程优化过程中,工序分析方法是消除信息阻塞、降低库存、产能提升、实施精益制造的一个有效工具。     

基于价值流的胖轴精益生产分析

为提高胖轴作业效率,通过调查,首先应用价值流图技术,绘制当前状态图,分析胖轴加工过程中存在的生产计划、在制品库存、生产方式等问题,区分胖轴加工中的增值和非增值部分;然后,依据精益思想和工业工程的基本手法,提出平衡物流、合并工序、拉动生产等改善措施,绘制未来状态图作为改善的路标。实施后,胖轴批量加工时间比原来减少54％,形成均衡、拉动生产,减少了在制品库存,使生产过程大为精简。     

基于价值流的S生产线的精益改善研究

以M公司S牌洗碗机内胆生产线为研究对象,绘制生产线价值流现状图,找出M公司S生产线中制约产能的瓶颈问题,结合精益生产的原理对生产线重新布置并进行平衡改善,消除了瓶颈,提高了企业的生产效率,证明了价值流图技术对洗碗机内胆生产线的改善具有很好的实用价值。     

基于价值流图技术的锁体生产系统优化

以某锁体生产线为实际研究对象,开展了生产线现场调研,收集了大量数据,进行了锁体生产线的价值流分析,明确了该生产线的生产流程,绘制了价值流现状图。在对现行流程中的主要浪费——“过量生产”和“库存”的产生原因进行分析的基础上,基于精益思想设计了锁体生产线价值流的未来状态图,确定了以生产链方式的价值流动生产方式,以看板－超市方式控制生产和库存,并对相关的生产计划、生产线平衡、质量控制、设备等进行了优化和改进。项目实施后生产周期减少928%;库存减少928%。     

干式变压器生产过程的工作研究

通过流程程序分析，对干式变压器生产过程中存在的重复、迂回和多余的内容进行了合并、简化或者取消，优化了生产工艺过程；通过操作分析和动作研究，对套装和叠铁等以手工操作为主的工序进行了改进，制定了标准操作法；通过时间研究，制定了各工序较为科学合理的时间定额。改进后，公司在不增加人员和设备的情况下，产品产量增加近1/3。     

面向对象的制造资源分类与生产规划调度模型研究

在分析制造资源信息构成的基础上，应用面向对象（0－O）的技术，研究制造资源的结构形式及其相互关系，建立了面向对象的制造资源结构模型，为建立制造资源类库乃至工艺知识和工艺数据库奠定了良好的基础，并对制造资源与生产规划调度（PPS）的关系模型进行了研究。     

基于Witness的汽车零部件生产物流系统仿真研究

在分析某企业汽车零部件生产物流系统基础上,采用Witness仿真软件对汽车零件的制造流程进行仿真研究。通过仿真发现该企业汽车零件生产物流系统存在的问题,进而提出改进方案。结果对比,设备利用率提高幅度91.43%;生产周期缩短幅度43.43%;生产率提高幅度67.80%。应用本论文研究结论可有效提高该企业的生产效率和效益,同时本论文也为其他制造企业的生产物流系统分析与改善提供了理论依据和方法。     

Methodology for Evaluating Manufacturability of Composite Materials

It is widely acknowledged that decisions made in the early design stages have a greater influence on the final product than those made in the later stages. In a conventional design process, composite products are designed without sufficient consideration being given to limitations of composite manufacturing process. Quite often some of composite designs cannot be produced with special performance requirement or cannot be produced at a reasonable cost. To resolve this drawback and achieve the competitive designs for composite product, an integrated knowledge framework that supports the quantitative manufacturability evaluation of composite design proposals was introduced. The essential concept of the composite manufacturability was defined through an in-depth analysis of composite manufacturing process. The evaluation flow was acquired according to the hierarchical indices. A stage-based quality assessment model for the composite multistage process was mainly studies. It relies on the consideration that the final quality of a composite product is mainly determined by some critical stages during a production cycle. Finally, the method is illustrated through a case focusing on the quality issue of void formation in autoclave process.     

Flow and social relationships of knowledge in science, technology and innovation: A patentometric study of UNICAMP’s technological production

The object is to identify the flux of information and get to know the socio-spatial and socioinstitutional dimensions of knowledge in the process of innovation, and to be able to visualize the impact and cognitive relationships of the sources of information used in the production of patents, as well as interactions and social cooperation that exists between the local innovative agents of The State University of Campinas. The research is of an exploratory nature with a case study design, in order to find out, by means of patentometric indicators, the flow and social relations characterized by cognitive and institutional aspects of local and regional knowledge based on the production of the Institution’s patents.     

Stall prediction of in-flight compressor due to flamming of refueling leakage near inlet

 The propagation of strong distortion at inlet of an axial compressor is investigated by applying the critical distortion line and the integral method. The practical applications, such as the inlet conditions of flaming of leakage fuel during mid-air refueling process, are implemented to show the details of the numerical methodology used in analysis of the axial flow compressor behavior and the propagation of inlet distortion. From the viewpoint of compressor efficiency, the propagation of inlet flow distortion is further described by a compressor critical performance and its critical characteristic. The simulated results present a useful physical insight to the significant effects of inlet parameters on the distortion extension, velocity, and compressor characteristics. The distortion level, incidence angle and the size of distortion area at compressor inlet, and the rotor blade speed are found being the major parameters affecting the mass flow rate of engine. Received: 20 October 2002 / Accepted: 28 January 2003 The authors would like to thank HQ RSAF of Air Logistic Department, Singapore for permission to publish this work, their financial support and encouragement.     

A two-dimensional model of the pressing section of a paper machine including dynamic capillary effects

Paper production is a problem with significant importance for society; it is also a challenging topic for scientific investigation. This study is concerned with the simulation of the pressing section of a paper machine. A two-dimensional model is developed to account for the water flow within the pressing zone. A Richards-type equation is used to describe the flow in the unsaturated zone. The dynamic capillary pressure–saturation relation is adopted for the paper production process. The mathematical model accounts for the coexistence of saturated and unsaturated zones in a multilayer computational domain. The discretization is performed by the MPFA-O method. Numerical experiments are carried out for parameters that are typical of the production process. The static and dynamic capillary pressure–saturation relations are tested to evaluate the influence of the dynamic capillary effect.     

汽车六角球头冷锻工艺优化与数值仿真

冷锻成形工艺是一种少无切削的净近成形工艺,以其精度高、生产效率高、低耗节能等优点,大量使用在汽车零配件的生产。六角球头销是汽车转向系统中的关键零件,其六角成形的质量直接影响到产品的使用性能。本文针对六角一次成形发生镦锻失稳问题,基于金属塑性成形理论,分析在镦锻过程中的金属流动,提出采用预成形工艺。根据产品结构,提出了大V锥形、锥形、锥六角形三种预成形工艺方案,采用DEFORM-3D对六角头成形方案进行数值仿真。为了得到最优参数,通过建立优化数学模型,对数值仿真获取的应力应变、损伤值分布、载荷进行优化得到最优方案。结合有限元数值分析对比分析三种方案,得到了预成形为锥形的成形效果最好,材料流动更为合理。经生产试验证明,通过预成形为锥形生产的六角头充填饱满,无不良缺陷,对生产同类型的成形工艺具有一定的参考价值。     

Investigation on flow characteristics of ice slurry in horizontal 90° elbow pipe by a CFD-PBM coupled model

Elbow pipes are important components for ice slurry pipeline transport. However, the flow characteristics of ice slurry in elbow are far from fully being understood, especially the influence of ice particle kinetics on ice particle size distribution (PSD). This study is intended to provide a better understanding of the behavior of ice slurry flow in elbow pipe. A CFD-PBM coupled model is employed to investigate the flow characteristics of ice slurry in horizontal 90° elbow pipe. The quadrature method of moments is utilized to solve the population balance equations. Based on the revised model, the flow characteristics of ice slurry in the horizontal 90° elbow pipe are investigated. The simulation results show that in the range of calculations, the pressure drop of elbow pipe is increased with the increase of velocity and ice packing fraction (IPF). An adverse pressure gradient is formed due to the change in flow direction. The emergence of secondary flow is caused by the centrifugal force. It makes the ice particles gather on the outer wall of the elbow section. The ice diameter increases along the flow direction due to the aggregation. The evolution of particle size distribution (PSD) is not significant. However, aggregation and stratification cannot be ignored in the process of long distance transport of ice slurry. The results are of significance for guiding the safety design and operation of ice slurry transportation.     

Virtual simulation of production line for ergonomics evaluation

To avoid ergonomic problems in the early planning stages of a production line and achieve more satisfactory planning and design, ergonomic simulation is
particularly important in digital production line planning. An ergonomics analysis method is presented by using two theories: Ovako working posture analysis system (OWAS) and Burandt-Schultetus hand-arm force analysis (BSHA). The processes of ergonomics analysis and simulation are discussed based on a platform of process simulation and process designer. As an example, the paper shows how ergonomics problems are considered in production line planning to make a better choice between different production line planning schemes.