涡轮叶片不同安装角缘板尺寸检测研究

涡轮叶片背向缘板空间尺寸复杂,缘板的位置尺寸保证叶片相互间的装配问题,正确理解缘板的空间位置平面形成,将缘板的空间一般位置平面转换为垂直状态,便于叶片缘板尺寸测量和测具的制造。在叶身不同转角+α度,0度,,-α度情况下,检测叶背的缘板尺寸,利用UG设计功能,采集不同转角下,叶身定位点的空间位置尺寸和叶身型面的切线方向进行定位,解决了曲面定位点手工无法计算的问题,提高了设计效率和准确性。     

叶片观察孔位置度检测的研究

随着发动机性能不断提高,对叶片的精度要求也越来越高,某叶片组件孔位置度检测测具,解决了上缘板孔位置度无法测量的难题,采用1套测具检查上缘板四孔位置度,满足生产需要,主要描述如何满足生产需求所需测具的设计过程。使叶片实现了一次定位夹紧,提高了叶片检测精度,避免了重复定位给叶片带来的累积误差。为了提高设计的准确性,采用三维UG建模设计,准确采集叶片型面参数,解决了繁琐的空间尺寸计算,提高了设计效率和准确性。     

运用"6σ"科学管理方法提高叶片测具使用周期的合格率

针对某机涡轮叶片测具使用周期的合格率较低的问题, 运用精益"6σ"管理理念,通过对该类测具流程状况的具体分析,利用"6σ"工具按照其中的精益思想将一些工具串联组合起来,统计各类影响因素的数据,分析产生问题的主要原因,有效地改善了流程过程中所存在的关键问题,并制定合理的控制措施.通过提高叶片测具的使用周期合格率,从而控制了该产品的检测质量.     

发动机叶片喉道面积检测研究

发动机叶片的喉道面积是发动机装配,调试的重要参数,喉道面积的测量是叶片装配的关键,叶片通道是由76个叶片的上下缘板和每两个叶片叶身型面之间构成的空间曲面通道,研究设计的喉道面积测具能准确地检测每个通道窗口间规定截面的通道宽度尺寸和上下缘板的通道高度尺寸计算出叶片的喉道面积。喉道面积的流量与发动机的推力有关,是影响发动机性能的重要因素,叶片喉道面积测具保证叶片通道排气量均匀。     

一种在精密平台上检测空间尺寸的方法

对专用测具空间尺寸的测量方法进行了分析研究,利用精密平台配备数显测高仪、杠杆千分表与标准滚(量)棒,采用双杠杆千分表交叉换位的方法对空间尺寸进行检测。测量方法比较和测量不确定度评定的结果表明,本文方法解决了以往使用单只千分表检测空间尺寸效率、精度较低的问题。     

几何公差控制角度偏差及角度公差分析

针对角度尺寸公差不能控制平面与平面之间的角度,而采用几何公差控制可能会导致角度偏差失去控制等问题,引入了被测要素附加贴切要素符号,实现用几何公差精准控制被测平面与基准面之间角度偏差,并给出了几何公差与角度公差的换算方法;针对装配层平面与平面之间角度偏差控制及累积计算问题,研究了多个零件装配后的角度尺寸链画法和角度尺寸链偏差累积计算方法;最后,以某型号电动木材切割机为例实现了用几何公差控制角度累积偏差以及各个零件上相关特征的几何公差与角度公差的转换,并分析计算了角度累积偏差。研究结果可为平面与平面之间的角度公差的分析控制及图样标注提供借鉴和参考。     

浅谈精铸涡轮叶片综合检测的设计

研究设计的精铸涡轮叶片综合测具能实现叶片叶身型面各截面理论位置的测量及叶片偏移、扭转后型面的测量,并同时在该测具上能实现缘板及叶冠内表面通道点的检测要求,使叶片实现了一次定位夹紧,多项检测,直接检测出型面与缘板及叶冠内表面的相互关系,提高了叶片检测精度,避免了重复定位给叶片带来的累积误差,降低了工装的设计制造成本,缩短了新产品研制的生产周期,提高了测量效率。为了提高设计的准确性,采用三维UG建模设计,准确采集叶片通道和型面参数,解决了繁琐的空间尺寸计算,提高了设计效率和准确性。它非常适用于精铸叶片加工生产现场,是一种结构简单,操作方便的检测工具。     

某机单晶叶片综合测量研究

根据定位、测量原理,保证叶片生产的质量前提,研究和设计了一种实用式的检测叶片型面的综合测具结构。由于该叶片是单晶组织控制的精密铸造叶片,是无余量的精铸叶片,它的曲率变化大、叶身长,定位的两个截面位置形式不同,在该测具上要检测无余量9个截面叶身型面、8个上下缘板通道点尺寸,而该测具X方向的定位点是由叶片两个截面(S10、S2)的进气边两点定位,Y向有榫头叶背方向的2点和S2截面上的1点共3点定位,其中叶型曲率变化大的截面型面上只有一点定位,这种情况测具的定位机构要注意它的稳定性;压紧机构要考虑叶片与定位面贴合度,并且要操作简单,装、夹方便快捷。这样叶片在测量中能得到稳定数据,满足工艺对叶片测量的需求。     

浅谈叶片缘板检测的工装设计

涡轮导向叶片是多个叶片成联精密铸造而成,这就给叶片检测提出了更高的要求,也给工装量具设计带来了一定困难,而且该导向叶片结构设计复杂,上、下缘板全部是空间曲面形成,测量空间窄小,侧面为双斜面,必须采用专用工装量具测量。通过了解用户使用要求,熟悉设计图,轴向需要一点定位,同时在一台测具内实现安装板尺寸检查,了解其它机种的检测方法,测量成联叶片安装板是生产的瓶颈问题,因此,解决成联叶片安装板弦长测量是摆在我们工装设计的重中之重的难题。     

异型零件空间尺寸测量方法的探讨

精确、高效、快捷、方便的质量检测已经是机械行业保证质量、信誉、市场等不可或缺的一种手段和环节。三坐标是现在最为快捷、精确的检测工具,而怎样利用好三坐标软件更好地为我们服务呢?对于异型零件空间尺寸的测量将被测要素转换成现有三坐标可识别的几何要素,利用三坐标测量机测量软件(PC-DMIS)通过拟合、构造被测特征元素,编制测量程序的方法解决异型零件不规则曲面空间交点尺寸测量的技术问题。     

涡轮叶片模具三维模型重构及误差分析

为了得到涡轮叶片模具制造误差量化分析结果,提出基于模型重构技术的误差检测方法。分别根据理论设计数据和实物测量数据建立了涡轮叶片模具的三维设计模型和实物模型,设计模型将为误差分析提供理论依据,通过两个模型配准和型面误差分析,得到量化制造误差。研究结果可用于类似的零件的数字化检测和误差分析。     

基于转动惯量的刚体9个惯性参数的测量

针对三维空间,提出了一种可以同时测量刚体9个惯性参数的新方法。利用气体静压轴承低速自由转动时其角速度是一个随时间衰减的单指数函数这一运动规律,测量物体绕任意轴的转动惯量,通过9次测量最终求出刚体的9个惯性参数。设计了一套物体惯性参数测量仪,该测量仪可以同时测量三维空间中物体的9个惯性参数。测量过程中无需重新装配,减少了中间测试量及人为干预误差,使测量时间缩短,测量精度提高。     

提高圆度误差分离精度的措施

以圆度误差分离技术为例,着重分析了影响分离精度的因素,提出了改善分离精度的数据有效性检验、集合平均、无附加相移数字滤波等措施。同时应用实例说明所述措施的必要性及实用性。     

The analysis of feature-based measurement error in coordinate metrology

Coordinate measurement systems (CMSs) dominate the dimensional control and diagnostics of various manufacturing processes. However, CMSs have inherent errors caused by the lack of a tracing ability for some of the measured part features. This is important for product inspection and process variation reduction in a number of automated manufacturing systems, such as for example the automotive body assembly process. The lack of a feature tracing ability means that instead of measuring a given feature, the CMS may actually measure the area around the selected feature. In this paper, a principle for the part feature tracing ability and the resultant feature-based measurement error analysis are developed to estimate the aforementioned deficiencies in the CMSs. The impact of feature type and part(s) positional variation on the feature-based measurement error is explored. The proposed approach is applicable to both contact and non-contact CMSs including both mechanical and optical coordinate measuring machines An analysis of the error for different measurement algorithms is presented. We show that the developed feature-based measurement error can have a significant impact on the measurement accuracy and hence on process control and the diagnostic algorithms currently used in manufacturing. A feature-based error map and error compensation approach are also developed and presented. Simulations, experimental results and two industrial case studies illustrate the proposed method.     

变面积电涡流传感器带冠叶片振动测量

为实现对各种带冠叶片的振动的非接触式测量,提出一种基于变面积型电涡流传感器的带冠叶片振动测量技术。当转子叶片进行高速旋转时,叶片扫过电涡流传感器,会使感应面积发生变化,后接高速数据采集分析处理系统,将面积变化信号进行处理,从而获得带冠叶片振动参数。在某型汽轮机末级带冠叶片上进行振动试验,试验结果表明变面积型电涡流传感器测振技术可以在转子高速旋转的情况下,准确测量带冠叶片振动情况,得到振动的幅值和频率,可以应用在实际带冠叶片的振动测量中,为转子叶片健康状况评估提供依据。     

Regularized multiframe phase-shifting algorithm for three-dimensional profilometry

In many industrial inspection systems, it is required to have a high-precision three-dimensional measurement of an object under test. A popular technique is phase-measuring profilometry. In this paper, we develop some phase-shifting algorithms (PSAs). We propose a novel smoothness constraint in a regularization framework; we call this the R-PSA method and show how to obtain the desired phase measure with an iterative procedure. Both the simulation and experimental results verify the efficacy of our algorithm compared with current multiframe PSAs for interferometric measurements.     

Extended Kalman filter-based sensor fusion for operational space control of a robot arm

Accurate measurements of positions, velocities, and accelerations in both joint and operational space are required for achieving accurate operational space motion control of robots. Servomotors used for joint actuation are normally equipped with position sensors and optionally with velocity sensors for interlink motion measurements. Further improvements in measurement accuracy can be obtained by equipping the robot arm with accelerometers for absolute acceleration measurement. In this paper, an extended Kalman filter is used for multisensor fusion. The real-time control algorithm was previously based on the assumption of a jerk represented as a processed white noise with the zero mean. In reality, the accelerations are varying in time during the arm motion, and the zero mean assumption is not valid, particularly during fast accelerating periods. In this paper, a model predictive control approach is used for predetermining next-time-step jerk such that the remaining term can be modeled as Gaussian white noise. Experimental results illustrate the effectiveness of the proposed sensor fusion approach.     

Vibration based damage detection of rotor blades in a gas turbine engine

This paper describes the problems concerning turbine rotor blade vibration that seriously impact the structural integrity of a developmental aero gas turbine. Experimental determination of vibration characteristics of rotor blades in an engine is very important from fatigue failure considerations. The blades under investigation are fabricated from nickel base super alloy through directionally solidified investment casting process. The blade surfaces are coated with platinum aluminide for oxidation protection. A three dimensional finite element modal analysis on a bladed disk was performed to know the likely blade resonances for a particular design in the speed range of operation. Experiments were conducted to assess vibration characteristics of bladed disk rotor during engine tests. Rotor blade vibrations were measured using non-intrusive stress measurement system, an indirect method of blade vibration measurement utilizing blade tip timing technique. Abnormalities observed in the vibration characteristics of the blade tip timing data measured during engine tests were used to detect the blade damage. Upon disassembly of the engine and subsequent fluorescent penetrant inspection, it was observed that three blades of the rotor assembly were identified to have damaged. These are the blades that exhibited vibration abnormalities as a result of large resonant vibration response while engine tests. Further, fractographic analysis performed on the blades revealed the mechanism of blade failures as fatigue related. The root cause of blade failure is established to be high cycle fatigue from the engine run data history although the blades were put into service for just 6 h of engine operation.     

采用CMM测量发动机叶片模具方法研究

为解决传统测量设备难以对组合型块进行准确测量的问题,提出了基于CMM的叶片模具数字化测量方法。利用PC-DIMS测量软件自动获取点的理论值及矢量方向,采用迭代法建立坐标系,选取对应的扫描轨迹生成方式,设置合适的扫描密度对叶片模具进行测量,并对结果进行三维补偿。利用此方法开展了轮廓度测量实验,绘制出叶片模具轮廓偏差图,并对测量不确定度进行评定。实验证明此方法测量准确性好、自动化程度高,可准确反映叶片模具在试制阶段及使用阶段的磨损情况,为模具的返修及保养提供了重要参考。     

某电厂600MW机组叶片断裂分析

某电厂600 MW超超临界机组在检修中发现一只低压叶片断裂,采用宏观分析、金相检验以及断口分析等方法对叶片断裂原因进行了分析。结果表明:叶片服役环境中存在能够引起叶片材料产生腐蚀的氯离子,导致叶片发生腐蚀疲劳断裂。