基于Flexsim仿真技术的混合装配线平衡优化

在制造企业装配过程中,混流装配能够提高物料利用率,满足顾客个性化需求,提高企业竞争能力。以某企业的一条混流装配线为例进行了研究,利用Flexsim仿真软件建立车间系统加工流程模型,对混流装配线进行仿真,进行平衡设计。通过对仿真输出数据的分析,得出装配线的"瓶颈"工位。最后为该装配线提出改进方案,并进行优化仿真,通过对改进前后方案仿真结果的对比分析,验证了改进方案的可行性。     

基于Flexsim的面膜生产线仿真与优化

针对S企业面膜加工车间现有生产能力无法满足订单需求的实际问题,建立了面膜生产线的Flexsim仿真分析模型,确定了生产线中的瓶颈工序。然后对生产流程提出相应的改善方案,再用Flexsim建模,验证方案的可行性。通过实例,体现了FIexsim在生产线仿真和物流系统规划的优越性。     

基于Flexsim的轮对压装生产线仿真优化

为了解决某企业转向架检修车间轮对压装生产线生产过程中出现的轮对堆积问题,通过对生产线的工艺流程、物流过程、加工标准工时等数据收集,运用和拓展Flexsim三维仿真软件建立了轮对压装生产线仿真模型。结合仿真运行中出现的堵塞现象以及仿真模型运行后的数据分析,确定轮对压装生产线中存在的"瓶颈"问题,提出相应的优化方案,并对优化前后的仿真数据进行对比分析。结果表明,此优化方案可显著降低生产线中某些工位的平均阻塞率、提高生产线产能,从而提高企业经济效益。     

基于Delmia/Quest的飞机装配线参数化仿真研究

为了解决传统经验或数学模型难以快速、合理的分析装配线产能、节拍的问题,以某飞机制造企业的一条装配线为研究对象,应用生产系统建模与仿真技术和工业工程方法,在梳理、分析其装配工艺流程、装备布局图及关键生产数据的基础上,利用Delmia/Quest仿真软件平台建立装配线参数化仿真模型,实现了装配线的实虚映射,并进行装配线装配流程仿真。通过对仿真数据输出结果的分析,获取了该装配线的生产瓶颈、生产产能、节拍、设备负荷率等相关数据,通过分析其生产特点,提出了针对性的改善方案,为该装配生产线设备配置的优化、工艺布局的评估提供了参考。     

生产线的设备规划布局设计与加工仿真的实现

生产线的设施规划布局设计作为制造系统设计的重要组成部分,它对生产设备的利用率、产品的生产与等待时间以及生产线的效率等都有密切关系。针对某企业机加工设备布局不合理现状,进行了机械加工设备布局方法及布局方案仿真技术的研究。通过分析设备布局的影响因素,建立了布局系统抽象模型,同时开发了设备布局原型系统,然后通过计算机仿真来预测系统的真实可用性,进而实现混合比加工零件的生产加工,仿真结果能够以图表或者文本的格式输出。通过在企业的实际应用表明,改进后的生产线设施规划布局方案能够有效地提高生产效率和设备利用率,仿真结果与实际结果比较接近。     

多层次仿真分析方法在制造流程改善中的应用研究

以企业制造流程改善为对象,将计算机仿真技术与IE理论相结合,建立了多层次仿真分析模型及分析方法。运用Ithink5．0仿真软件和标准作业组合票等工具,实现了生产线与工作单元两级仿真分析模型,并以典型产品为例,进行了生产线瓶颈分布识别和工序分析,进而提出了生产线制造流程改善方案,对有效提高生产线的产能起到了积极的作用。最后,对生产系统多层次仿真分析方法的扩展应用前景进行了展望。     

数字化制造系统规划与建模仿真研究

通过对离散制造系统规划、建模与仿真分析,研究数字化制造系统面向对象的仿真建模方法.利用仿真技术对制造系统的运行的性能进行分析与评价,可以在生产计划的早期,对制造系统进行规划设计、参数优化和结构调整,验证工艺,优化生产过程,提高生产效率.以实际生产系统缸盖加工生产线为例,建立生产线仿真模型,进行布局规划、瓶颈分析,对生产线设计方案进行验证,优化生产线的配置和布局.     

FMS800柔性生产线的研制与应用

介绍了FMS800柔性生产线的组成以及功能实现,FMS800柔性生产线包括两台KHC80μ主机、物流系统以及控制系统组成。该柔性生产线能实现多工件的混流加工,是智能化生产车间的关键生产条件和实现基础。     

基于Open CASCADE的桁架机器人数控加工生产线的仿真设计与实现

通过仿真系统的研究与实现能够完成示教编程中桁架机器人在加工过程中的仿真运动过程.文章首先对应用于数控加工生产线的桁架机器人进行分析,将其模块化,然后利用UG对桁架机器人进行建模;通过对加工生产线的工作流程的分析,得到桁架机器人的运动过程;通过Open CASCADE几何内核与MFC框架的结合,以离线示教编程的形式进行三维实体模型的运动学仿真以及界面设计,最后,完成整个软件系统的开发.     

基于叶轮等复杂部件的智能制造生产线设计

为了解决复杂部件加工制造工艺的复杂性,以叶轮等复杂部件的智能制造生产线设计为基础,通过智能制造生产线的工艺分析和设计方案,结合机器视觉、智能检测、智能物流和工业互联等技术进行产线仿真与验证。结果表明：该智能制造生产线设计不仅满足生产要求、工作运行稳定,而且实现生产过程的自动化、信息化和智能化,满足多品种小批量产品的定制化混流生产,达到为企业降本增效的目的。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。