数字刀具测量系统的研究

刀具的几何参数是影响数控机床加工精度和生产效率的重要因素。研究了基于计算机视觉检测技术的高精度刀具测量系统,分析了运行原理和功能模块,并对关键技术做了论述。系统实现了对刀具的刀尖切削特征点、圆弧半径和切削角参数的自动精确测量,并将数值反馈到数控机床刀具数据库,具有较高的效率、精度和自动化程度。实验结果证明,系统测量重复性精度可达3μm。     

CCD在数控机床闭环控制系统中的应用

高精度测量是实现高精度控制的前提。通过对现有数控机床控制系统的分析,为了提高测量精度、降低系统成本,将传统光栅与CCD结合起来完成数控机床闭环系统的控制,介绍了系统位移测量原理及方法,为数控机床闭环控制提供新思路。     

数控机床检测功能开发

文章利用数控机床坐标轴移动的特性，将数控机床功能加以扩展。在数控机床上附加测量头、控制盒、摄像头及计算机装置组成的测量系统，使数控机床具有一定的检测功能。论文首先介绍了检测系统的总体方案，然后介绍了系统的硬件配置及软件设计。     

数控机床上测头系统测量程序的开发

测头系统是一种高精度的检测装置,安装在数控机床上可实现刀具测量、基准面找正、工件坐标设定、工件在线检测等功能.在对测头系统的作用、组成、工作原理进行分析的基础上,以在加工中心上自动找正凸圆圆心为例,介绍测头系统测量程序的编制方法,使数控机床的操作变得更加简单、便捷、精确、高效,同时为其他相关程序的编制提供参考.     

积极检查装置——单刀或多刀加工用的自动测量、自动补偿装置

本文介绍数控机床上单刀或多刀加工的自动测量、自动补偿装置,用于控制孔径尺寸。     

基于机器视觉的影像测量仪自动寻边技术研究

影像测量仪的应用之一是对数控机床加工出来的零件进行测量,确保加工过程的精确性.在影像测量仪的自动寻边系统中,针对影像测量快速准确的要求,对寻边的路径提取和跟踪算法进行了改进.根据边缘线与图像视窗交点的不同情况,采用改进的行列交叉搜索法和切向跟踪法进行边缘路径提取和跟踪.在ubuntu10.04系统下,结合Opencv和C语言开发了整个系统的图像处理软件.实验对比表明,该自动寻边算法具有更高的寻边效率且边缘提取更准确,能为数控机床的加工提供更加精确的数据信息.     

利用宏程序实现FANUC反向间隙自动测量与补偿

针对传统使用百分表手动检测数控机床反向间隙过程中人工介入较多,测量效率低等缺点,提出了一种结合高精度测头和FANUC数控系统G31高速跳转信号,利用宏程序实现"傻瓜"式一键操作进行反向间隙自动测量与自动补偿的方案。分析了自动检测系统的检测原理,介绍了系统的硬件电气连接,给出了关键宏程序代码。最后以Renishaw激光干涉仪为工具,比较了利用该方法自动测量和补偿反向间隙前后的机床精度。试验数据证明该自动检测系统能有效地调整机床的反向间隙,从而提高机床的定位精度。     

数控机床螺距误差实时补偿

介绍了双频激光干涉仪的测试原理及测量方法,根据双频激光干涉仪对数控机床螺距误差的测量结果,利用校准软件对数控机床的螺距误差进行自动补偿.     

五轴数控机床三维空间标准球测量研究

高效测量标准球球心坐标对保证五轴数控机床精度、校准机床精度至关重要。针对五轴数控机床的通用形式,结合空间坐标变换计算,基于空间标准球及接触式探针测量法,提出了一种空间标准球球心自动测量方法,并研发了一种基于MATLAB的标准球球心测量分析软件。通过实验及仿真,对HU40-T及T-2五轴数控机床的空间标准球进行测量,测量最大误差分别为0.078 mm及0.02 mm,测量过程无碰撞干涉。研究结果证明了空间标准球球心测量方法的有效性及准确性,测量精度高,满足应用要求。     

柔性生产系统用的通用部件系列

本文介绍了一种为适应柔性生产系统需要而发展的新型通用部件。介绍了此种新型通用部件的特点及用此种通用部件所构成的多品种加工自动线、自动换箱加工系统、具有可变性的数控机床、制造单元等实例,还涉及了柔性制造系统的外围设备、输送、测量、控制及故障诊断等问题。图17幅。     

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.     

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.     

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.