Design of the Controller for the Non-circular Gear Hobbing Based on Nios H Processor

将基于FPGA的嵌入式软核处理器NiosⅡ应用于非圆齿轮滚齿加工控制,可以很好地满足非圆齿轮滚切过程中所需要的实时变传动比要求及利用FPGA实现电子齿轮合成运动,利用其硬件实现I/O处理及精插补算法,软件、硬件协同完成高精度、高速度控制.     

非圆齿轮数控滚齿的一种插补方法

在分析目前常用的非圆齿轮滚齿插补方法不足的基础上,采用三次样条来拟合非圆齿轮的节曲线,进而提出了数控滚齿的一种插补方法.采用该插补方法,非圆齿轮的滚齿加工可以在一段数控程序内完成,减少了加工时的速度波动,提高了加工精度和加工效率.     

基于NiosⅡ的非圆齿轮滚齿加工控制器设计

将基于FPGA的嵌入式软核处理器NiosⅡ应用于非圆齿轮滚齿加工控制,可以很好地满足非圆齿轮滚切过程中所需要的实时变传动比要求及利用FPGA实现电子齿轮合成运动,利用其硬件实现I/O处理及精插补算法,软件、硬件协同完成高精度、高速度控制。     

梯形速度控制变插补周期的实时插补算法研究

提出了基于梯形速度控制的变插补周期实时插补算法.在固定插补步长条件下,依据直线加减速算法,确定出加速段、恒速段和减速段的插补次数,进而生成变化的进给速度和相应的插补周期;同时,形成各坐标轴的运动增量.仿真实例结果表明,该算法可有效地控制加工精度,充分发挥联动各轴的加速能力,有效缩短加减速过程时间,且易于在CNC系统中实现.     

非圆齿轮数控滚齿与插齿加工的自动编程系统开发

根据非圆齿轮节曲线方程或传动比要求及非圆齿轮的数控滚齿和数控插齿的加工原理,推导出数控滚齿机和数控插齿机各运动轴的联动,基于VB,开发了能自动生成加工非圆齿轮的数控滚齿和插齿的数控加工代码的系统,系统界面友好,适用性强。     

特殊齿廓齿轮数控磨削加工技术的研究

提出了一种使用普通蜗杆砂轮数控加工特殊齿廓齿轮的方法;针对要求加工的特殊齿廓,提出了一种基于数值算法的渐开线旋转定位方法;利用砂轮的径向、切向联动变位原理,研究了基于六轴五联动数控系统采用普通蜗杆砂轮磨削特殊齿廓齿轮的联动控制模型,给出了实时插补脉冲量计算方法;并编制了相应的计算机仿真程序,验证了该加工方法的可行性,从而实现普通蜗杆砂轮高效地磨削特殊齿廓齿轮。     

基于MCX314As的低速走丝电火花线切割机运动控制系统研究

以低速走丝线切割机为研究对象,提出了硬件插补的4轴联动控制方案,设计了基于单片机和运动控制芯片MCX314As为核心的运动控制系统的硬件体系结构.设计和编制了软件系统,重点研究了利用MCX314As硬件插补功能实现4轴联动功能以完成锥度切割的方法.通过模拟实验验证,该运动控制系统能满足低速走丝线切割机对运动控制系统的要求.     

基于NiosⅡ和FPGA的数字运动控制系统研制

目前国内较先进的数字运动控制系统采用MCU+CPLD的结构,存在电路复杂、成本高及高速运动控制时无法满足精度要求的缺点.在FPGA内部开发以NiosⅡ为核心的数字运动控制系统,采用软件实现速度控制及粗插补算法,利用硬件实现PCI控制器、I/O处理及精插补算法,软硬件协同完成高精度、高速运动控制,该系统体积小、实时性强,在高速加工时,能够稳定实现较高精度要求.     

基于结构参数的齿轮滚削力计算和精度影响研究

通过分析圆柱齿轮的滚切加工过程,获得了每一个刀齿的切屑层状态;根据齿轮和刀具的结构参数,利用单位切削力的计算方法,推导出主切削力的计算公式,得到了切削过程的切削力的变化规律.通过建立滚刀的力学模型,对刀具进行了变形分析,并对变形影响齿轮展成加工精度的程度进行了研究;推导了刀齿发生径向误差和转角误差时被加工齿轮的实际包络方程和产生的齿轮法向误差计算公式;对滚齿机床设计、刀具的设计制造以及齿轮加工过程的进一步研究等方面具有一定的指导意义.     

基于开放式数控的滚齿机零编程系统开发

结合齿轮与刀具啮合机制与运动关系,在分析滚齿加工工艺的基础上,建立滚齿加工参数模型和零编程的数学模型,研究数控滚齿加工NC程序自动生成技术;结合滚齿加工的功能需求,提出开放式数控滚齿机的零编程系统架构,完成了人机交互、编程算法及各功能模块设计,并进行了功能测试,基本达到预期设计要求。     

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.     

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.     

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.