灯具罩旋压机专用数控系统的设计与实现

在灯具罩生产行业至今没有由专用数控系统组成的旋压机床,大部分由通用数控机床改造而成,故数控系统功能浪费、数控旋压机床成本高。因此,采用工控机、伺服驱动器和变频器等硬件设备,设计了灯具罩数控旋压机床的电气控制系统,并根据灯具罩的几何形状和旋压加工工艺,开发了灯具罩旋压轨迹控制模型,在此基础上研制了灯具罩数控旋压机床的专用数控系统。该系统只要将模具参数、加工轨迹外轮廓参数和灯具罩加工参数输入专用数控系统,就可以按照设定算法自动生成加工轨迹图,滚刀按照轨迹图自动进行旋压加工,从而实现加工过程的全自动控制。     

数控精密微孔电火花加工机床燃油电喷片自动加工系统研究

针对数控精密微孔电火花加工机床研发设计了一种片式工件的自动上下料机构,是构成数控精密微孔电火花加工机床燃油电喷片自动加工系统的重要部分,实现了汽车发动机燃油电喷片的高效、低成本及自动化加工。     

深孔数控加工自动编程技术的研究

对数控深孔加工工艺及编程技术进行研究,并在基于UG软件二次开发平台上,利用VC++编程语言开发了深孔钻3D自动编程系统。成功地将数控深孔机床传统加工的看图取数、手工编程的方式,转变为直接从3D模型自动取数编程。实现自动获取孔的位置参数、加工深度,自动对不同直径的孔进行排序,解决了深孔加工在交叉贯穿过孔无法实现自动变速的难题。在不占用机床加工时间状态下自动生成加工程序,从而达到加工参数的准确性,避免2D数据和3D图档不一致和操作失误造成的加工出错导致的经济损失。有效提高机床使用率和编程效率,节约加工成本。     

筒形件强力旋压CAD/CAM系统

简单介绍了组成强力旋压ＣＡＤ／ＣＡＭ系统的产品信息图形输入模块、工艺参数自动设计模块、数据库系统、自动编程模块、数据采集和处理系统、加工参数实时补偿系统等几部分的功能。说明使用该系统，可缩短产品工艺设计和数控编程时间，明显改进旋压产品的质量，降低试验次数，降低废品率，具有极大的经济效益。     

基于PC的开放式数控系统的开发

基于PC＋MPC02运动控制器开发了一套开放式数控铣床系统,该系统具有图形自动编程、加工仿真、实时监控机床加工等功能。本文介绍了该系统软、硬件组成和实现方法。     

实现数控编程自动化的新思路

实现数控编程自动化的新思路湖南大学李琨，孙宗禹主题词切削加工，ＮＣ，自动编程近年来，ＮＣ机床，尤其是ＭＣ，在我国机械制造企业中的拥有量增长很快，已逐渐成为保证产品质量、提高生产效率、增强企业应变能力的主要设备。为了充分发挥这些先进机床的潜力，如何提高...     

卧式数控旋压机床用多工序自动旋轮库的研制

根据大型筒形件成形时多工序加工要求和旋压机床的结构特点,设计了一种卧式数控旋压机床用多工序自动旋轮库,重点介绍了自动旋轮更换装置的设计、旋压力的计算、旋轮头轴承配置、旋轮座结构以及直线导轨副的选择.该旋轮库采用了旋轮头与旋轮座分离的更换装置及由基座、纵向滑架与纵向横向滑架组成的旋轮座,可实现筒形件加工所需要的多道次拉深旋压、变薄旋压、切边、卷边等4工序成形所需旋轮、翻边轮及切边轮的自动装卡,极大地提高了生产效率、设备的利用率和自动化程度,从而降低了生产成本、减轻了工人的劳动强度.     

五轴联动机床的轨迹控制研究

在分析了目前的数控加工自动编程系统后,提出了一种以仿真实现五轴联动机床轨迹控制的新方法.该方法首先从提取加工路径信息入手,建立了仿真所需要的驱动函数.然后在ADAMS平台上,从加工起点发起仿真运动.加工过程仿真产生的各轴运动参数信息,直接为五轴联动机床的数控编程提供了控制依据.一个圆柱凸轮加工仿真的实例证明,用仿真结果替代传统控制算法,使得五轴联动机床的数控编程变得更加容易和快捷.该方法同样适合解决其它多轴联动设备的轨迹控制.     

塑胶模具电极自动编程的开发与应用

分析了电极数控加工编程的特点,通过加工区域智能识别与选取,刀具路径策略模板化和策略参数自动设置实现了电极数控加工编程的自动化。在实际生产的应用中,大大提高了加工效率,避免了人工编程错误的发生。     

基于特征加工技术在自动数控编程中的应用

应用MasterCam软件的FBM Mill和FBM Drill两类基于特征加工功能,实现实体零件的自动数控编程.首先.在Solidworks软件中完成实体零件的特征建模,将模型导入至MasterCam软件;然后,设置零件的毛坯尺寸及FBM参数,在指定的机床上自动生成所有特征零件加工部分的二维刀具路径:最后利用数控加工仿真验证了自动生成的基于特征的NC刀具轨迹.采用基于特征加工技术消除了实体零件铣削和钻削编程操作中所涉及的特征识别的手动工艺流程,大大提高了编程效率与编程灵活性,是实现自动数控编程的一种有效方法和手段.     

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。