22000kN大型伺服压力机电控系统研究与实现

介绍了基于发那科伺服系统的大型伺服压力机机械结构及特点,并简单介绍了压力机多连杆的传动方式;结合伺服压力机的电气控制方式及特点,对发那科控制系统进行了阐述。将自主研发的上下位机系统与发那科动力系统相结合,实现整个伺服压力机自动化系统,并给出了其优异的性能指标。证明了此方案适合用于伺服压力机控制系统。     

多连杆压力机模块化运动学性能分析

机械压力机适用于薄板件拉深、成形、弯曲、冲裁等冷冲压工艺。进行多连杆压力机的杆系类型分析；基于杆组法建立其模块化性能分析方法；进行多连杆压力机的模块化运动学性能分析软件开发；基于所开发的模块化压力机性能分析软件，进行了对称六连杆肘杆压力机和对称八连杆肘杆伺服压力机的算例分析。研究为多连杆压力机的杆系设计提供了辅助分析工具。     

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。     

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。     

精密智能型伺服压力机运行模式分析

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精密智能型伺服压力机,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。分析了伺服压力机多种工作运行模式。介绍了该伺服压力机的装配过程中出现的新工艺,针对调试过程中发现的问题,作了进一步优化改进,大大提高了下死点精度,有利于提高精密智能型伺服压力机性能。     

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。     

机械压力机交流伺服电动机直接驱动方式合理性探讨

阐述了交流伺服电动机的特点及应用，分析了机械压力所采用的各种驱动方式，即普通不可调速交流异步电动机一飞轮联合驱动和可调速交流异步电动机一飞轮联合驱动以及交流伺服电动机直接驱动，进一步从力、功率及元件选取的角度分析交流伺服电动机直接驱动型机械压力机的合理性，最后分析比较了相同公称压力的现有的日本小松公司生产的交流伺服电动机驱动型机械压力机和西安锻压机床厂生产的多连杆机械压力机及普通机械压力机的各方面的性能特点。     

伺服压力机数字控制系统的设计

分析了伺服曲柄连杆压力机工艺特征要求和伺服电机矢量控制基本原理,提出了基于DSP与FPGA的数字伺服电机矢量控制系统,并对系统相关软硬件及其构成进行了详细设计和分析.采用性价比优越的TMS320F28335DSP和EP2C20F484C8 FPGA相关功能器件和相关软件系统的模块化设计方法,可实现对曲柄连杆压力机滑块任...     

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。     

交流伺服式机械压力机及其关键技术探讨

论述了制造业是中国的治国之本、兴国之器、强国之基,而先进的装备制造业是我国当前与未来重点的发展领域。分析了机器由机械本体系统与电气控制系统组成,而机械本体系统分别由动力源、传动部件和工作机构组成,明确指出直驱与近零传动是未来机器的发展方向。对比分析了交流异步电动机与交流永磁同步伺服电动机的优缺点,指出交流永磁同步伺服电动机是机械压力机的理想动力源。第三代锻压设备的交流伺服式机械压力机及其驱动与传动的三种典型方式分别为小型压机用丝杠-带轮式、中型压机用带轮-偏载丝杠-肘杆式、大中型压机则采用带轮-多级齿轮-曲柄滑块式。分析了国内外伺服压力机的产品现状,中大吨位的伺服压力机常采用多个交流伺服同步电动机共同驱动的方式。对交流伺服式机械压力机的关键技术进行了探讨,为我国伺服压力机追赶国际先进水平奠定坚实的基础。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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.