智能伺服压力机选型计算分析

根据曲柄连杆压力机工艺要求和交流伺服系统控制原理,研制开发了SIP-160伺服压力机,取消了机械飞轮和离合器,实现了伺服压力机的柔性化和智能化控制。分析了伺服电机与伺服驱动器的选型计算。介绍了该伺服压力机的控制方法,针对调试过程中发现的问题,作了进一步优化监控程序,有利于提高智能型伺服压力机性能。     

交流伺服压力机及其关键技术

交流伺服电机驱动是目前成形装备发展的一个新方向,不但可以实现成形装备柔性化和智能化,还可以提高生产率和产品质量、节能环保.本文介绍了交流伺服传动的基本原理、交流伺服压力机发展现状并就其中若干关键技术问题发表了看法:大功率交流伺服电机及其驱动控制技术;交流伺服传动过程能量的回收;无飞轮压力机传动系统设计;重载高效精密螺旋传动技术;基于伺服压力机的成形工艺优化等.文章还就交流伺服压力机的发展趋势进行了展望.     

金属板材加工设备发展新动向--2004上海国际金属板材加工设备展览会

综述了目前国内外金属板材加工设备发展的最新动态,重点介绍了高速精密压力机、数。控回转头压力机、板料折弯机、伺服曲柄压力机以及交流伺服驱动技术在成形装备中的应用。     

基于PC控制技术的伺服机械压力机控制系统设计

伺服机械压力机是"数控一代"的机械压力机,其控制系统直接影响压力机的功能和性能。在对伺服机械压力机控制要求进行分析的基础上,基于PC控制技术,对伺服机械压力机的控制系统进行了设计,包括:控制器的选择、控制构架的搭建、曲轴与滑块位置的检测以及滑块轨迹的规划与控制等。采用基于PC的控制器,开发了实验样机,并对典型伺服冲压工艺进行了实验测试。实验结果表明,该伺服机械压力机的控制系统可实现包含变速、停止和反向等运动的伺服冲压工艺的规划控制,具有良好的控制性能。     

曲柄连杆伺服压力机控制模型的研究及系统实现

本文根据伺服电机和曲柄压力机的工作原理,推导并建立了曲柄伺服压力机的控制模型,并给出了状态空间的描述,提出了曲柄伺服压力机控制系统的实现方法。本文的研究成果,对伺服压力机控制和成形工艺参数的优化,提供一定的参考依据。     

交流伺服机械压力机在金属塑性成形加工中的应用(Ⅰ)——板料成形

伺服机械压力机的突出优点是智能、高效、节能。它兼有液压机和机械压力机的特性,不但动作敏捷,而且可在任意点停留保压,滑块运动可实现编程控制,这就为成形新工艺的开发提供了一个强有力的工具。介绍了目前国内外伺服机械压力机在板料成形加工领域的典型应用实例,包括大型汽车覆盖件伺服机械压力机冲压生产线、基于伺服机械压力机的超高强度钢板的热冲压生产线、高质量绿色冲裁工艺、精密弯曲、高效拉深、镁合金板热冲压等。通过设计滑块特殊的运动模式,实现了普通机械压力机上不可能完成的新工艺。还就如何加快伺服成形技术的应用步伐提出了一些看法,在加强新装备技术研究的同时,还必须注重基于新装备的应用工艺研究。     

多连杆伺服压力机控制系统的设计

根据曲柄连杆压力机工艺要求和伺服电机控制的原理,研制开发了1600kN多连杆伺服压力机,取消了机械飞轮和离合器,实现了伺服压力机的柔性化和智能化控制。编写了控制系统软件程序及监控画面多个操作界面,介绍了该压力机的传动系统方案和交流伺服驱动控制系统组成,建立了六连杆数学模型。计算结果表明,六连杆有明显增力放大作用,有利于伺服压力机进一步优化机械结构以及降低成本。     

机械压力机伺服直驱式新型永磁电动机的设计与应用研究

为了研究用于机械压力机的伺服直驱式新型永磁电动机,对压力机传动机构的合理方式进行了探讨,从而确定对伺服直驱电机的性能要求。对各类新型永磁电动机分别进行介绍,确定适合于压力机伺服驱动的拓扑结构,并制作样机和电机性能测试平台以验证直驱电机的性能特性。研制了通用型伺服驱动器,对电机各相绕组电流进行独立控制,使磁阻转矩得到合理利用,同时提高了弱磁升速能力。讨论了压力机减速制动过程中能量储存的方式,并研制了外转子开关磁通永磁电机和飞轮一体式储能系统,使伺服压力机更好地展现了节能减排方面的优势。     

伺服机械传动优化精冲工艺的动态性能

随着新技术的发展及在冲压领域的应用,精冲一加工工艺也在持续的改善和优化。伺服控制技术在精冲压力机设备上得到了广泛的应用。新型伺服机械式精冲机由与偏载轮直接相联的伺服马达驱动,无离合器或飞轮。由于此新型结构和马达速度完全可控．针对不同零件的冲压工艺要求．设备可精确控制加工工艺过程中不同时刻的动作和压力．精密调整滑块行程曲线。与传统的机械式精冲机和液压精冲机相比,生产效率更高、零件质量更好、模具使用寿命更长。     

伺服压力机位置/压力自动补偿精确运动控制研究

为了满足机械伺服压力机压力精确控制的需求,设计了一种位置/压力自动补偿精确控制的运动控制系统。首先,分析了发那科控制系统位置/压力控制原理;然后,在压力机上设计位置/压力自动补偿运动控制系统,系统通过回归校正算法提高了应变压力传感器的反馈精度,结合发那科伺服电机与控制器实现位置模式和压力模式的平稳切换;最终,实现伺服压力机位置和压力的精确自适应控制。对伺服压力机不同压力负载控制情况下压力反馈曲线和压力与位置的响应特性曲线进行分析,结果表明,本控制系统满足伺服压力机位置与压力控制的精度和稳定性的要求。     

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).     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.