旋转接触式三座标测量仪的计算机控制系统设计

针对叶片泵定子这种复杂曲线类零件的测量,介绍了一种由VC 开发的计算机测量控制系统,采用旋转接触式三座标测量仪通过计算机控制对定子曲线进行测定。用待定系数法和函数最优法,得到数据文件并自动绘制经数据拟合后的曲线图形。该测控系统较一般的三座标轴测量机在结构上要简单,软件设计上也有其独到之处。     

非接触三维曲面测量仪及其在多点成形中的应用

为了解决金属板材的回弹问题,也为了检测多点成形零件的精度及省去靠木模工序,利用激光测头研制了非接触测量仪.对多点成形的零件形状进行检测,利用开发测量仪专用软件,分析成形零件的形状误差,把形状误差值反馈到多点成形软件里,实现多点成形的第二次造型、计算、分析、调形、成形及测量的闭环多点成形.本测量仪适用于板材二维和三维曲面的测量和曲面拟合,可用于车辆、飞机、轮船以及各种压力容器等覆盖件的测量.     

全自动影像测量仪中双相机精确定位方法研究

为了实现影像测量仪双相机的精确定位,以满足批量多种类零件自动化测量需求。在现有的影像测量仪上引入由大视野相机构成的视觉引导模块,文中以改进后的影像测量仪为平台,利用大视野相机得到标定板的角点位置信息,结合小视野相机获得的实际位置信息,通过仿射变换建立两者之间的坐标转换关系,确定双相机之间的位置关系,实现双相机之间的相互精确定位。定位实验结果表明了文章所提方法的有效性,相对于传统定位方法其定位精度提高了16%,能够满足批量多种类零件自动化测量的需求,为后续的自动测量工作奠定了基础。     

板料成形三维全场应变摄影测量快速检测系统研究

针对目前板料成形过程中应变测量的实际问题,提出了一种新的测量方案,通过采用近景工业摄影测量与坐标网格分析法相结合的方法,可以高效地实现板料成形后表面全场应变的精确测量。基于以上方法设计并开发出了可以应用于实际的板料应变检测系统XJTUSM。通过对某些型号的钣金零件表面应变的测量,验证了本文方法的有效性。     

用于齿轮淬火的圆柱坐标机器人单元

文章结合机车用齿轮淬火设备的研发,介绍了一种广义圆柱坐标式数控机器人式设备.文中对本机器人操作机的结构、参数、控制系统的构成及功能等作了介绍.最后对所开发的机器人式设备的实际应用情况进行了说明.     

基于最小区域法的圆柱度几何误差评定

在建立圆柱度几何误差最小区域评定规划模型的基础上,将最小区域法应用于圆柱度几何误差的优化评定中,实现了利用最小区域法对圆柱度几何误差规划模型的优化求解.以轴类零件的圆柱度的测量评定为例,通过对实际测量数据的误差评定,并将评定结果与现有的优化算法结果进行对比,结果表明基于最小区域法的圆柱度几何误差评定具有评定精度高等优点,具有较强的应用性和推广性.     

精密外圆磨削圆柱度在位测量与补偿工艺

圆柱度是评价轴类零件加工精度的重要指标,通过对精密轴类零件外圆磨削过程中圆柱度误差产生机制的研究,获得适用于精密外圆磨削的圆柱度误差在位测量工艺,并实现可视化定量在位补偿,大大提高了传统外圆磨削的精度和效率,减轻了对操作者经验的依赖程度。     

复合式坐标测量技术在模具测量中的应用

介绍了复合式坐标测量技术的应用实例，以及选择坐标测量仪时应注意的一些问题。     

涡轮逆向工程设计

介绍了利用接触式坐标测量仪和Pro/E提供的曲面造型功能 ,实现了涡轮数字化的逆向工程设计 ,避免了产品传统模拟式复制方式的弊病 ,实现了涡轮的再设计 ,从而为复杂产品的数字化逆向工程设计提供了一种切实可行的方法。     

基于逆向工程的电话壳快速原型制造技术研究

利用三维坐标测量仪,测出电话壳的点云,将测量的点云数据用IMAGEWARE软件进行处理后,利用Pro/E软件的曲面造型功能,做出电话壳的CAD模型,再采用三维打印机Zprinter310系统打印出电话壳的原型,实现了逆向电话壳到快速原型的快速设计与制造.在产品设计研发过程中,使用逆向工程和快速原型制造,对缩短产品研发周期、快速响应市场有显著效果.     

Geometric and quasi-static thermal error compensation for a laser digitizer equipped coordinate measuring machine

An emerging trend in dimensional inspection of manufactured parts is the use of coordinate measuring machines (CMMs) equipped with non-contact laser digitizers instead of traditional contact probes. Error mapping is generally proprietary to the CMM controller, and the accuracy of such a combined system is limited by the lack of integrated CMM/laser digitizer error compensation. This paper reports progress towards achieving such a system.Geometric error compensation measurements are made on a test machine at 20, 25 and 30 °C. Performance of the system was tested by measuring a special optically coated sphere ballbar artifact. The scan coordinates, the CMM axis scale positions and temperature were recorded simultaneously in real time. The CMM error compensation data was then used to post process the laser digitizer coordinates to obtain improved global part coordinates.Inclusion of the error compensation terms is shown to reduce the dispersion of results by 65 to 80%.     

Analysis of Formation and Interfacial WC Dissolution Behavior of WC-Co/Invar Laser-TIG Welded Joints

During the valve fabrication, hard metal is welded to stainless steel or invar alloy for sealing purposes because of its good heat resistance operating at 500 °C. However, WC (tungsten carbide) dissolution in weld pool softens the hard metal and decreases mechanical properties near the hard metal/weld interface. In order to analyze the WC dissolution in welded joint, joining of hard metal and invar alloy was carried out using laser-tungsten inert gas hybrid welding method. Microstructures of the weld region, chemical composition were investigated using optical microscope, scanning electron microscopy, and EDAX, respectively. Mechanical properties such as microhardness and four-point bend strength test were performed. Larger and smaller WC dissolution and WC dissolution through transition layer based on thermo-dynamics were discussed. The results thus indicate that WC dissolution led to cellular microstructure, columnar crystal, and transition layer under the effect of laser beam and tungsten arc. WC dissolution was affected by metal ions Fe⁺, Ni⁺, Co⁺ exchange in W-M-C system, and WC grain growth was driven by forces caused by laser beam and tungsten arc in larger WC, smaller WC, and liquid Fe, Ni systems.     

基于冷金属过渡的电弧增材制造钛合金螺旋桨成形机理及组织性能

通过对基于冷金属过渡(CMT)的电弧增材制造成形过程中电弧形态、电流电压同步信号和熔池形貌的同步检测分析,研究了电弧不同阶段的熔滴过渡形式和熔池金属的受力状态,探明了悬垂结构成形过程中的熔池金属的受力机制,实现了钛合金螺旋桨的成形,并分析成形后的组织性能。研究结果表明,通过对CMT电弧热输入和电弧力的精细控制,能够在无支撑条件下实现螺旋桨叶片的快速成形,同时获得良好的力学性能。在本研究条件下,钛合金CMT增材制造过程中熔滴过渡主要以短路过渡的形式进行,降低基值和短路阶段的焊接电流能够增加悬垂结构倾角,且当I基值/I峰值小于0.3时,钛合金螺旋桨最大倾角达到53.26°。基于优化后的工艺成形船用Ti6321合金,内部组织致密且无贯穿式的粗大柱状晶,力学性能达到同级别锻件标准,水平方向和竖直方向的各向异性不明显。     

软硬模辊式冲压模具设计及工艺优化

软硬模辊式冲压模具解决了传统钢质模辊冲装置存在的干涉问题,但在实际使用中仍存在诸多缺陷,如:上下辊的易调节操纵性差、板料冲裁加工变形大等。结合冲压模具的实际应用情况,对软硬模辊式冲压模具进行了结构改进和冲头优化设计。优化调整了下辊高度的楔形机构,保证冲压时的重叠量且更容易实现上下辊的水平度;将辊式冲压机上的平刃口圆柱冲头改为中空内斜刃冲头,减小了冲压后产生的塌陷深度,提高了板料的平整度。经计算仿真和实验验证,表明本文所提出的优化方案切实可行,能够有效提高冲压质量。     

基于三坐标测量机的精密叶轮测量路径规划研究

研究了精密叶轮的三坐标测量机(CMM)测量路径规划,首先进行了精密叶轮的顶层测量规划:被测零件的定位、CMM测头的空间姿态优化和坐标系的匹配。然后实现了精密叶轮的底层测量路径规划:测量点的选择、分组、排序。采用参数线法生成了理论测量路径,分析了CMM各种扫描测量方式,构造了边界曲面,并对精密叶轮表面采用UV曲面划分测量,从而实现了对精密叶轮的CMM测量。     

变极性脉冲MIG焊的控制

研究变极性脉冲MIC焊的主要目的是控制形成浅焯缝,高效焊接铝合金薄板变极性脉冲MIG蚌的控制系统由逆史控制系统和单片机控制系统构成。控制系统协调控制电弧极性、电弧稳定性、焊丝熔化及熔滴过渡、电弧电压等焊接参数,获得稳定的焊接过程。变极性脉冲MIG焊在电弧EP极性时,利用脉冲电流熔化焊丝、形成熔滴过渡,电弧EN极性时电弧沿焊丝端上爬,EN极性电孤促进焊丝熔化、减小电弧对熔池的加热作用,减小焊缝熔深,焊接薄板时其有独特优势。     

A probing question: A customer''s investigation into the directional variability of a coordinate measuring machine touch trigger probe

The accuracy of measurements produced by coordinate measuring machines (CMMs) is constrained by a number of factors.Most machines use the Renishaw Touch Trigger probe to generate a signal and identify a point at which measurement coordinates are recorded. Under ideal conditions the measuring errors generated by this action are negligible when compared with typical drawing tolerances. This holds good as long as the measuring uncertainty of both the CMM and probe system are regularly checked and maintained. Furthermore the mode of operation can contribute to an accumulation of errors which can result in unnecessarily large variation.This paper presents the first part of an investigation which addresses these problems.The outcome provides useful guidelines for CMM users seeking to minimise measurement variation.     

外加磁场对碳弧堆焊层组织及性能的影响

采用碳弧堆焊方法对Cr-B-Ni-V系铁基合金堆焊时加入直流横向磁场,来细化堆焊层金属的组织,控制硬质相的形态及分布.通过对堆焊层进行硬度、磨损试验和显微组织的分析,得出了磁场强度对堆焊层金属的硬度和耐磨性的影响规律.结果表明,施加磁场比未施加磁场的堆焊层硬度高,耐磨性好;磁场参数与堆焊工艺参数相匹配时,堆焊层的性能达到最佳,即磁场电流3 A,堆焊电流180 A,堆焊速度12 cm/min时,堆焊层硬度最高,耐磨性最好,此时堆焊层中硬质相细小、分布均匀,且呈"六角形",方向一致.     

基于CMES编程实现汽车零部件自动测量的探讨

介绍数控三坐标测量机系统的组成以及测量软件CMES的特点;以汽车零部件为测量对象,探讨了运用CMES编程实现汽车零部件自动测量的方法,指出三坐标测量技术在产品开发和质量控制中的意义和发展前景。     

Laser digitizer-based sheet metal strain and surface analysis

This paper presents a new approach to sheet metal strain and surface analysis using data collected with a high-accuracy coordinate measuring machine mounted laser digitizer. First, the flat sheet metal blank is electrochemically etched with a hollow centre circular grid pattern. As the blank is pressed into the desired shape, the resulting strain deforms the circles into approximately elliptical shapes. The sheet metal is then laser digitized every 0.1 mm and the (X,Y,Z) surface coordinates plus reflected light intensity (grey level) are simultaneously recorded. Parallel computer-based image processing separates the darker ellipse grid points from the lighter background, and orthogonal least-squares data fitting estimates the major and minor surfaces strains. Results can be presented as a forming limit diagram, or as a derived thickness strain plot. Surface analysis is achieved by computing and plotting a maximum curvature map and then quantifying feature depth as the normal direction amplitude between the locally highest and lowest points. Implementation of the research for a representative industrial part is included.