一个改进的单抓钩周期性排序模型及其在自动化学处理线中的应用

计算机控制的抓钩广泛用于自动化学处理线的工件的运送。抓钩的排序直接影响系统的生产率，抓钩排序的目标是对运送进行排序以极大化生产率。当某工序处理时间非常长时，该工序成为瓶颈。为了去除该瓶颈，系统可以为该工序设计多个处理槽，这称为“多重处理槽”问题。本文提出一个改进的混合整数规划模型以求解有“多重处理槽”的单抓钩周期性排序问题的最优解。实例表明所提出的方法是有效的。     

基于价值流的飞机蒙皮族零件生产精益改善

为构建飞机蒙皮族零件精益生产单元,以公司目前的生产管理现状为切入点,绘制典型蒙皮族零件价值流图,找出加工过程中存在的瓶颈工序、生产计划粗放、钣金加工周期长等问题。以精益思想为指导,分别从拉动式物料需求、拉伸瓶颈工序优化、钣金加工工艺优化3个方面提出改善措施,实现生产过程精益化。实践证明,飞机蒙皮族零件交付周期缩短了30.0%,产能提高了26.8 %,创造直接经济收益55.1万元/a。     

批制造业中考虑多工序能力平衡的提前／拖期生产计划方法

在跟踪当今提前／拖期生产计划问题研究现状的基础上，针对考虑多工序能力平衡的提前／拖期生产计划方法的瓶颈问题，提出了两种解决方法－关键工序法和松驰法，为将集ＭＲＰ与ＪＩＴ于一体的Ｐｕｓｈ／Ｐｕｌｌ混合策略应用于实际架起了桥梁。     

浅谈减少小修作业无效工序的方法

本文针对作业过程中重复无效工序多的问题，提出了通过采取事前分析，事中控制、事后总结提高的方法建立对工序风险的评估和控制，健全对工序风险的预防，努力降低无效工序发生的几率的对策，节约了生产成本，提高了怍业单位精细管理水平。     

基于均衡生产的煤矿主煤流运输系统关键工序效率优化

为了解决X煤矿主煤流运输系统效率低、均衡性差的问题,以关键工序（主井提升）为研究切入点,提出了煤矿主煤流运输系统关键工序效率优化、提升方法。该方法针对主煤流运输系统瓶颈产生的主要因素,利用人机联合作业图确定消除瓶颈的途径。通过采用串行作业改为并行作业,动作经济原则优化动作,改变员工更换频次的手段,使每循环作业时间缩短15.82 s。优化方法使主煤流运输系统平衡率提高9.52%,节拍降低24.06%,日产量提高982.13 t,表明该优化方法的可行性与有效性。     

插口组装线的产能分析和平衡改善

基于生产线平衡原理和基础工业工程(IE)手法,以作业测定为依据研究插口组装线的产能和平衡状况,针对产能过剩工序和瓶颈工序,分析工艺流程及操作,提出了持续改善方案.并对改善结果进行分析,在减少了一道工序的基础上使产能满足需求,平衡率达到预期目的.     

基于改进田口方法的轮毂装配过程质量控制研究

针对风力机轮毂装配工序的质量控制问题，结合多品种小批量生产模式的特点，提出了一种面向定位布置的轮毂装配关键工序识别与监控的方法。综合考虑轮毂装配生产中的成本因素及相对质量损失，制定装配工序的质量特性损失标准，采用改进的质量损失函数识别轮毂装配关键工序；为解决统计过程控制（SPC）方法应用于小批量生产模式的瓶颈，引入基于直觉模糊集的工序相似性分析与评定方法，通过分析工序相似性的影响因素，构建轮毂装配成组工序相似性评判指标体系及评定模型，完成工序相似性的测度。最终使用SPC方法监控管理轮毂装配关键工序，确保轮毂的装配质量。该研究为小批量生产模式中运用SPC方法管理过程质量提供了理论依据。     

HTBS微耕机包装线仿真与优化

针对HTBS公司微耕机产能提升的紧迫性,分析了微耕机生产线工段——包装线的工位作业及工序流程;依据秒表测时法所测数据,结合Flexsim仿真技术分析包装线瓶颈;运用经验排序法对包装线瓶颈工位工序及其他工位工序进行合理排序,以平衡各工位负荷,并通过Flexsim建立优化后的包装线仿真模型验证其有效性。微耕机包装线优化后,生产线平衡率由66.67%提高到90.77%,日产量由354台提高到436台,平衡优化效果明显。     

光伏电池片生产车间智能物流调度研究

为实现光伏电池片生产车间物流的智能化改造,提出以最大化瓶颈工序机台产能的方式来最大化生产车间产能,并设计相关数学模型和智能物流调度算法。首先,通过对光伏电池片生产车间的问题描述与分析,建立以瓶颈工序机台产能最大化（瓶颈工序机台总停机时间最短）为目标的数学模型。然后,设计了嵌入模型约束规则的车间智能物流调度算法,包括物料调度算法、AGV选择与路径规划、AGV碰撞避免策略设计等,并提出了另一种物料调度算法作为对照方案。最后,通过仿真实验与分析,证明了所设计模型及智能物流调度算法的高效性及适用性,给予车间管理人员相应的管理启示。     

成组单元的作业排序

多品种小批量生产中为提高生产率和经济效益采用成组技术。作业排序是成组技术管理工作中的一个重要问题。本文从多工序成组作业排序的基本方法中着重介绍了一种方法,并结合生产实际应用分析如何进行修正的方法。文中还结合分析对比其他几种方法,指出了本文介绍方法的优点。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...