叶片进排气边智能磨削检测一体化系统

为了实现对叶片进排气边的高精度、高效率和高一致性的加工与检测,本文在光学扫描测量技术和柔性砂轮自适应磨削技术的基础上,搭建了叶片进排气边智能磨削检测一体化系统。该系统以智能制造的设计理念为核心,包括了在线测量系统、机器人系统、柔性磨削系统和智能制造控制系统等多个子系统。在应用过程中,首先采用光学坐标测量机对叶片进排气边进行快速的数字化测量并建立加工余量模型,然后在磨削专家系统的协调和控制下,利用工业机器人抓取叶片并执行磨削运动和叶片工位传递,最后在柔性砂轮上完成进排气边的自适应磨削加工,从而完成了进排气边的"测量-磨削-测量"的自动化全过程。本文在该系统上进行了叶片进排气边的磨削与检测实验,从而对系统的加工精度及加工方案的可行性进行了验证。实验结果表明,该系统的加工精度和效率能够满足叶片现代化生产的要求,具有很大的现实意义和实际应用价值。     

面轮廓度误差的坐标测量方法和评定

面轮廓度误差的测量方法有仿形法、截面轮廓样板法、光学跟踪法和坐标法。前三种方法不仅需要制作精度较高的轮廓样板或多个测量截面的理想轮廓,而且样板轮廓的制造精度和测量截面理想轮廓的制作精度会影响测量精度。其中截面轮廓样板法和光学跟踪法都是用测量线轮廓度误差来评定面轮廓度误差,     

叶片型面的三坐标测量数据处理及误差分析与补偿

三坐标测量机进行接触式测量时,一般采用球形测头。在测量过程中,测量机采集的是测头中心的坐标值,在测量常规几何要素（如平面、球、圆柱等）时,测量软件可以根据被测量要素的数学模型自动进行测头半径的补偿。但在测量叶片等没有预设数学模型的零件时,测量软件无法自动进行测头半径补偿。叶片具有复杂的空间几何形状,一般包括榫头和叶身两部分。叶身的形状复杂,没有任何数学模型,通常采用截面法来描述,即用多个平行的理想平面与叶身相截,每个截面又根据需要取一定数量的点,通过截面位置和截面内点的位置来描述整个叶片的形状。因此对叶片型面的测量就是要获得这些点的位置数据。叶片各个截面的形状不同,并存在叶身空间的扭曲和倾斜,因此叶片型面的测量尤其是半径补偿技术的应用具有特殊性,     

传动元件的有控点共轭啮合运动几何测量法

一、概述就传动元件几何形状精度的评定观点及相应的测量方法和原理而言 ,其测量法大体可分为三类。1 .几何坐标测量法这种测量法的基点在于被测件是一个几何实体。建立一个基准测量坐标系 ,将被测工件 (它有自身的坐标系 )放置在该测量坐标系中去进行度量。按照工件坐标系和测量坐标系的关系 ,测量出该工件上被检测轮廓形状 (点、线、面 )和理论虚拟几何体上相应处轮廓形状 (点、线、面 )的差异 ,它可归结为测量对应点坐标位置的差异 ,即测量头与被测传动元件之间为点接触 ,所测量的误差数值 ,为被测工件表面实际轮廓上对应该检测点的轮廓…     

同步规划测量式叶片免形状精密测头系统

针对叶片测量测头灵活性差、无法兼顾精度和效率的问题,提出了一种免形状、高精度测头系统技术方案。首先基于"同步规划测量"思想,研发了新型免形状光学测头系统,然后分析了系统的工作原理、理论模型和关键技术,最后进行了实验研究,验证了方案的可行性和测头系统的精度水平。研究结果表明,该测头系统在无需输入叶片理论模型数据和姿态精调的情况下,自动进行路径规划并同步完成叶片型面数据的采集。测点数据的采集全部在传感器基准距离附近完成,从而有效地限制了倾角误差,综合测量精度控制在10μm以内。该测头系统具有算法简单、高精度、免形状等特点,在叶片类空间自由曲面测量领域具有较好的应用前景。     

基于Roboguide的叶片边缘机器人磨削加工方法与仿真

采用精密锻造方法制造的航发叶片具有更优异的综合力学性能,且锻造成型后叶片的叶身型面不需要二次加工,仅对其边缘进行加工处理即可达到技术要求,制造工艺更简单。目前叶片进排气边缘加工主要采用线切割机床切边后手工打磨,效率较低,产品一致性差,严重影响叶片的气动性能。采用机器人砂带磨削方式加工进排气边缘,应用截平面法和曲率差值法,计算磨削加工中的行距和步长,规划磨削加工路径,生成机器人加工轨迹,并基于Roboguide进行了虚拟仿真验证,可有效提高加工质量与效率。     

机床在线测量技术的应用及发展

现代模具制造技术已经迈向高精度、智能化、高速化,对在线测量的要求越来越高。同时,随着现代加工制造设备发展,数控机床的线性精度和几何精度也越来越高,控制器的功能越来越强大,这使得人们可以利用机床本身配以测头系统来实现对加工工件的在线测量,或刀具自动测量及检测。     

基于AFM的纳米尺度线宽计量模型及其算法的研究

纳米尺度线宽的测量广泛应用于半导体制造、数据存储、微机电系统等领域。随着制造技术的进步,线宽的极限尺寸也变得越来越小,目前已经缩小至100 nm左右。在这一尺度范围内,由于样本制造技术的限制和测量仪器的影响,目前很难得到准确的测量结果。为了获得样本的真实几何尺寸信息,剔除测量方法和仪器本身对测量结果的影响,建立了一个基于AFM测量技术的线宽计量模型和相应算法。该模型将被测样本的截面轮廓用20个关键点分成5个部分共19段,用基于最小二乘的直线来拟合实际轮廓。应用该模型和算法可以分别得到单刻线轮廓拟合前后的顶部线宽b_T、b_(TF),中部线宽b_M、b_(MF),底部线宽b_B、b_(BF),左右边墙角A_L、A_R,以及高度h_。使用NanoScope Ⅲa型AFM对一个单晶硅(Si)线宽样本进行了测量,测量结果表明该模型和算法可以满足纳米尺度线宽计量的基本要求。     

叶片型面在线检测方法研究

叶片是航空发动机的关键零件,确保叶片的型面质量对提高发动机的整机生能和工作效率具有重要作用.对叶片接触式在线检测进行研究,以提高叶片测量的效率和精度,介绍了接触式在线检测的原理及实现,重点讨论了叶片在线检测的关键技术检测点的布置和规划.提出了UV截面法生成待测曲线的新方法,并结合了叶片轮廓加工的特点,试验和仿真表明,该方法可有效的提高叶片测量的效率和精度.     

基于结构光的叶片自动检测系统研发

针对三坐标检测叶片型面时成本高、检测轮廓有限,以及光学扫描检测时难以快速、自动、完整扫描的问题,设计了基于结构光扫描仪的叶片自动化检测系统。PCI运动控制卡作为上位运动控制器,带细分的步进电机作为动力元件,完成了三自由度的自动化检测系统搭建和叶片扫描检测。实验结果表明,合理的扫描规划高效地完成了整个叶片的扫描,并依托点云数据快速地实现了整个叶片三维逆向重构与检测。对比结构光学检测与三坐标的截面轮廓检测精度,该检测系统能够快速地获取检测模型并准确地完成整个叶片精度检测,提高了效率,降低了成本。     

[刀具及切削工艺]一种基于几何调控的辊轧叶片前后缘加工曲面自适应重建方法

针对航空发动机压气机辊轧叶片前后缘溢料端数控加工问题,提出了一种基于设计曲面几何调控的前后缘加工曲面自适应重建方法。根据自由变形理论以及曲面能量控制原理,建立了具有变形约束能力的自由曲面几何调控模型;利用该模型建立了基于遗传算法求解的辊轧叶片前后缘加工曲面自适应重建策略。该策略通过微量调整叶片设计曲面几何形状,使其在逼近叶身型面测量数据的同时尽可能维持初始几何形状,最终实现了辊轧叶片前后缘加工曲面的自适应重建。实例验证结果表明：利用该方法获得的辊轧叶片前后缘加工曲面可以在保证叶片形状精度的同时实现其与实际叶身的圆滑转接。     

Design of the cross-structural cathodes in electrochemical machining of aero-engine blades

Blades are crucial parts of aero-engines. Their manufacturing is difficult because of their thinness, complex profile and stringent requirements. Electrochemical machining (ECM) is an important approach for manufacturing blades, but it is difficult to machine the leading and trailing edges. This article adopts cross-structural cathodes in ECM to solve the open electric field space problem. The key difficulty in the design of cross-structural cathodes is the position of the crossed-point. The height and the offset of the crossed-point are optimized using the ANSYS software. The simulation results show that the position of the crossed-point obviously affects the machining accuracy, along the leading and trailing edges of the blade. A pair of cross-structural cathodes with one uniform section is designed, and a series of corresponding ECM experiments are carried out. The experiments demonstrate that the ECM process is stable, the profiles are sleek and the machining dimensional error is reduced to 0.08 mm at the leading and trailing edges of the blade when using the new cathode structure.     

A novel spiral machining approach for blades modeled with four patches

This paper aims at developing a novel spiral machining technique for four- or five-axis milling of blades. The main contributions are twofold. First, detailed algorithms are presented to model the blade surface with the idea that it can be separated into four patches, i.e., the pressure surface, the suction surface, the leading edge surface, and the trailing edge surface. The G¹ continuity across the boundary of each patch is considered. Second, based on the four patches modeled, the key routine of a new spiral machining method is further addressed in detail. It is carried out by machining the pressure and suction surfaces actually whereas passing by the leading and trailing edges in air cut. Experimental results show that the proposed methods can improve the machining quality and avoid overcut near the leading and trailing edges.     

The selection of radius correction method in the case of coordinate measurements applicable for turbine blades

The objective of the research presented in the paper is the selection of suitable probe radius correction method in the case of coordinate measurements which can be applied for turbine blades. The investigations are based on theoretical analysis of geometric data and on further computer simulation of measurements and data processing. In the paper two methods for computing coordinates of corrected measured points are verified. Those so-called local methods of probe radius correction are based on Bézier curves. They are dedicated first of all to coordinate measurements of free-form surfaces which are characterized by big values of curvature, e.g. those surrounding the leading and trailing edges of a turbine blade. Numerical simulations are done for several models of the cross-sections of turbine blades with diversified magnitudes of radii of curvature. There are considered both manufacturing deviations and coordinate measurement uncertainty of each examined profile of a turbine blade. Numerical investigations based on the developed analytical models show the advantage of the algorithm which uses the second degree Bézier curves in probe radius correction. Moreover, in the paper there is explained the implementation of the developed algorithms for probe radius correction into the standard CMM software which amplifies the usability of the algorithms.     

开式整体叶轮数控加工技术研究

研究了开式整体叶轮数控加工技术.首先分析了该类零件的几何特点以及加工难点,然后提出了一套适合于开式整体叶轮数控加工的关键技术,包括流道可加工性分析、前后缘走刀步长计算以及刀轴矢量的生成及其平滑处理.比较了分片铣削和整片铣削加工方式,提出采用整片铣削代替接刀痕严重的分片铣削加工方式.加工实例表明,该技术是有效的,所加工零件的误差控制在设计允许公差范围内,达到了设计要求.     

Measurement of the geometric features of a cutting tool edge with the aid of a digital image processing technique

For the further development of new machining systems such as flexible manufacturing systems (FMS), this paper reports on a new measuring system developed for the multi-purpose understanding of the geometric features of cutting tool edges having serious influences on the machining outputs. In this system, to detect three-dimensional (3D) features of the toolface and tool flank only from the two-dimensional (2D) microscopic observation of the toolface and to describe an overall 3D geometric feature of the tooledge as a digital 2D image as well as to enable inexpensive system development, two convenient measuring principles are used. These are the scanning optical section method for the toolface contour mapping and the cutting edge profile comparison method for the flank wear landwidth estimation. Based on these, experimental hardware was arranged and various processing softwares were developed. They were applied to an observation of the cutting edge wear development in some cylindrical turning experiments, to show that various effective cutting edge parameters could be easily extracted from the integrated toolface image recorded, and that sufficient accuracy and resolution for practical use could be obtained.     

激光在机测量系统的实现

为了能在加工航空发动机关键零部件(如叶片)等复杂曲面零件的过程中实现快速在机测量,研制了非接触式激光在机测量系统。分别介绍了测量系统的工作原理,机械结构和电控系统。该系统主要由激光测头、无线传输电路、可充电锂电池、转接基座、刀柄和外壳等部分组成。为了实现机床的加工模式与测量模式之间的快速切换,其采用刀柄式的安装方式,从加工叶片切换到在机测量时,机床只要运行换刀程序,即可实现叶片加工到叶片测量的转换。此外文中还针对在机测量系统的电控部分研制了通过无线传输的数据采集系统。为了验证所研制的在机测量系统的实用性和有效性,在五轴叶片加工中心上进行了叶片截面测量实验,结果显示其测量精度为20μm,测量时间为10min。验证结果表明所研制的激光在机测量系统能够高效精确地完成叶片型面的测量任务。     

A practical sampling method for profile measurement of complex blades

Blade is one of the most important parts in turbine machinery. The complex geometry of blades not only makes them difficult to fabricate, but also leads them difficult to inspect. Typically, the surface of blades is measured by using coordinate measuring machine (CMM). Since the measurement time and cost increase proportionally as the increase of measurement points, it is essential to sample measurement points which can represent entire blade with sufficient confidence and accuracy. In order to achieve a certain allowable deviation with a suitable set of points, a practical sampling method for surface measurement of blades was studied. Firstly, the leading edge curve and trailing edge curve were supposed to represent the twisted and bend information of blades. A sampling method based on maximum chordal deviation for leading edge curve and trailing edge curve was researched. Further, a fusion approach for sampling points on both edge curves, which determine the cross-sections, was proposed. Secondly, the inspection points sampling method for sectional curves were investigated. Finally, two simulation and one experimental examples were used to demonstrate the sampling methodology. The results indicated that the approach of this study can ensure the measurement precision at high curvature potion by measuring a small number of points.     

叶片后缘加厚对轴流风机性能的影响

为解决NACA65系列翼型叶片后缘轮廓线内切圆半径收敛至0引起的铸造工艺问题,采用三次多项式函数生成叶片后缘厚度函数,精确调整叶片后缘末端厚度.基于Ansys软件对不同叶片后缘厚度的风机进行流体仿真,并分析其气动性能与静力结构特性.结果表明叶片后缘增厚使得叶片附面层分离损失增加,尾迹与叶栅主流区的掺混损失增大.叶片载荷...     

整体涡轮大扭曲叶片电解精加工方法与试验研究

材料为高温合金的整体涡轮盘,其大扭曲叶片加工一直是制造业中的难题。提出多轴联动复合平面摆动展成电解方法加工大扭曲叶片,用一次进给电解实现叶盆、叶背面加工;分析复合平面摆动展成电解加工叶片型面成形规律,优化复合摆动展成电解加工数控编程及阴极结构设计,解决叶背出气边电解过切、根部三角区过切、出口短路等关键工艺问题;进行摆动式展成进给电解试验与分析,一次电解可达叶盆、叶背型面精加工要求。