数控铣床的多功能与多坐标技术

介绍了在三坐标数控铣床上实现的多功能数控技术和将三坐标数控铣床发展为四、五坐标三联动数控铣床的理论及技术,并研制了相应的数控自动编程软件。     

面向飞机大部件的智能三坐标辅助测量技术研究

为实现飞机大部件型面的高精度、高效率和自动化三维测量,对测量的关键技术进行了研究,研制出一套面向飞机大部件的智能三坐标辅助测量系统。该系统以导航小车为平台,以夹持有靶标的直角三坐标伺服机构为载体,通过激光跟踪仪实时反馈靶标位置进行闭环控制实现误差补偿,采用离线编程对导航小车和直角三坐标伺服机构进行任务规划,在保证测量精度和测量范围的同时实现了产品的自动化测量。实验结果表明,该测量系统简单有效,适用范围广,具有较大推广价值。       

三坐标测量机的自动测量和应用

模具制造业中,传统检测方式由于速度及检测能力等原因成为制约生产的瓶颈。计算机技术在产品质量管理应用方面仅限于单项检测技术,未形成完整的质量系统。三坐标测量机具有测量空间大、通用性强等特点,是制造业中收集质量数据的主要检测设备。随着三坐标测量机在电子、航空等工业领域广泛应用,CMM技术得到了广泛研究。由于缺少自动建模软件需人工调节,因此从三坐标测量机测量原理出发,讨论三坐标测量机应用问题,并提出了相关的解决方法。     

基于校企合作的三坐标测量机在质检专业中的应用探究

在分析陕西国防工业职业技术学院质检专业三坐标测量机实训开展情况的基础上,指出了传统实训过程存在的问题,并在校企合作新模式下,探讨与规划三坐标测量机的师资配置、实训内容、校外基地建设等实施方案,提出校企共建师资、校企协同开发实训方案、校企共建实训基地及开发服务功能等策略,以有效安排学生实训各个环节,改善三坐标测量机实训教学效果,推进质检专业实践教学改革。同时,开发三坐标测量机社会培训与服务功能,开创新型校企合作关系,提升职业院校质检专业社会影响力。实践证明,在校企合作模式下进行三坐标测量机实训,有效提高了学生学习兴趣与实训效果,使得学生对三坐标测量机的应用有了更深层次的认识,一定程度上提高了学生的就业竞争力。     

整体叶轮五坐标加工与三坐标检测一体化技术的研究

分析了整体叶轮的几何形状特点和加工难点,介绍了在UG7.0上采用细分技术,拟合生成样条曲线,利用三坐标测量仪检测技术对加工好的整体叶轮各种尺寸进行检验,提出了整体叶轮设计、加工与三坐标检测于一体化的方法。     

坐标测量机的最新进展

三坐标测量机是量仪产品中的支持产品,本文介绍了三坐标测量机的最新发展,对从事三坐标测量机的设计、开发技术人员,以及欲购买三坐标测量机的人员均有一定参考价值,对一般从事测量工作的专业人员,也可从中了解三坐标测量机的发展趋势。     

三坐标测量机在航空发动机零部件检测中的运用分析

三坐标测量机在航空发动机零部件检测中,往往因为三坐标选择的型号（含精度）、测量功能、测量方法等因素造成测量数据不准确、测量效率低等。为了能够提高三坐标测量机在航空发动机零部件检测中的应用效果,对三坐标测量机发展进行了简要介绍,并针对三坐标测量机在航空发动机零部件检测应用中存在的这些问题,从航空发动机零部件特点、三坐标测量机检测航空发动机零部件的具体测量方法出发,本文提出了一些在现场特别适用的运用指导方法,希望可以改进三坐标测量机在航空发动机零部件检测中的应用效果。     

浅谈气缸套同轴度在三坐标上的正确测量

本文介绍了气缸套同轴度在三坐标上的正确测量方法,利用三坐标测量机进行检测,三坐标测量既直观又方便,且测量精度高,可以大幅度的降低生产成本,缩短生产周期,但由于不正确的评价方式,可能会出现测量结果误差很大,从而误导生产过程的控制.     

测量精英 各显神通

三坐标测量机作为一种高效率的精密测量仪器,已广泛地应用于机械制造、电子、汽车与航空航天等工业中。利用三坐标测量机可方便地进行空间三维尺寸的测量,并能实现在线检测及自动化测量。在本届展会上,三坐标测量机与其他精密测量产品成为展出亮点之一。     

哈量集团三维扫描式测头研制成功

精密量仪系列产品是哈量集团重点研发的项目之一,三维扫描式测头作为三坐标测量机和齿轮测量中心等仪器的主要功能部件,其重要性不言而喻。目前国内市场对精密量仪产品的需求量十分大,但国内尚无一家企业可以批量生产三维扫描式测头,市场上的三坐标测量机和齿轮测量中心等仪器需要的三维扫描式测头都依赖进口。     

某大型米波雷达天线结构设计

为快速完成天线结构设计,提出一种决策评估与仿真优化相结合的设计方法。针对某大型米波天线结构设计需求,利用该方法首先完成天线单元的概念设计;然后利用计算机仿真,对设计方案进行抗风校核;最后根据仿真结果,对方案进行优化以满足设计需求。     

CMM uncertainty analysis with factorial design

The purpose of this research is to present a method to estimate the Coordinate Measuring Machine (CMM) measurement uncertainty. The approach is based on a performance test using a ball bar gauge and a factorial design technique. A factorial design was applied to carry out a performance test and to investigate CMM errors associated to orientation and length in the work volume. The CMM measurement uncertainty was estimated with components of variance obtained after statistical analysis of variance applied to volumetric measurement errors. An application was performed with a Moving Bridge CMM and the results were compared to the volumetric performance test proposed by ANSI/ASME B89.4.1 standard. The results showed that the proposed method is suitable to investigate CMM hardware performance and determine the contribution of machine variables to measurement uncertainty.     

使用高精度三坐标测量仪实现透镜定中心

传统的光学测量定中心法受限于光源、转台大小和装调误差传递性而不适用于大口径、多透镜光学系统的装调,为此本文提出了使用三坐标测量仪接触式测定透镜中心的精密机械测量法。介绍了使用三坐标测量仪测量大口径透镜中心偏的原理,即在测量透镜上表面与基准轴等距离各点坐标的基础上拟合得到透镜光轴与基准轴的夹角,从而解算出透镜的中心偏。通过大口径长焦距镜头的装调对该方法进行了检验。检验结果表明:该透镜的装调偏差为6.47″,重复性误差为(1.16×10-4)″。该方法将光学测量变为机械测量,利于装调,可在保证装调精度的同时简化装调难度,提升装调效率,满足大口径多透镜光学系统对高精度装调的要求。     

Measuring-sequence planning by the nearest neighbour method and the refinement method

This paper focuses on the measurement, using a coordinate measuring machine (CMM), of the shape of a workpiece made up of geometric elements. It explores how a CMM can complete the whole measuring process with an optimised measuring sequence to reduce measuring time, after a CAD/CAM software system has planned the number and positions of the measurement points. In this paper, the nearest neighbour method and the refinement method are proposed to plan the measuring sequence. The nearest neighbour method uses individual element faces as the subject of planning. It takes the position closest to the starting point as the initial measuring face, and then gradually completes the sequence of all points. It arranges the sequence of measurement points on the initial measurement face by means of the nearest neighbour method as described in the aforementioned algorithm. It calculates the distance between the final point on the initial measurement face and all of the unmeasured points on the other faces. The point with the shortest distance between the final point on the initial measurement face and all of the unmeasured points on the other faces is selected as the next measurement point and the measurement face of this selected point is considered as the next initial measurement face. It determines whether all of the faces and measurement points are completely planned. The refinement method does not distinguish among element faces, but treats all planning points as the goal. The method is often used to handle the measurement-sequence problem where a large area and a large number of points are involved. The CAD/CAM software and power of calculation and analytical capability of the system can quickly obtain a suitable measuring sequence.     

Improving repeatability of coordinate measuring machines with shaped command signals

Performance of coordinate measuring machines (CMMs) is adversely effected by structural vibrations. The effect of input shaping, a method of reducing residual vibration, on the quality of CMM measurements has been investigated. Measurements of a CMM show a reduction of structural deflection when input shaping is used. Additional tests indicate that input shaping improves measurement repeatability over a large range of operating parameters.     

免形状测量机的误差分离技术研究

免形状(Form-free)测量机是基于零件"小偏差假设",不依赖被测对象的几何形状、无须知道几何参数、无须精密定位的情况下,也能进行几何尺寸和形状误差的测量与评定的测量机。针对此测量机,建立了误差补偿综合模型,为测量机误差测量和补偿提供了理论基础。提出基于激光追踪仪的几何误差分离方法,快速准确实现对测量机几何误差的检定。使用软件对分离算法进行仿真及实验,结果证明该分离算法是可行的,并将其与激光干涉仪测得的误差比较,两者非常吻合,证明此算法具有快速、精度高等优点,适用于坐标测量机的几何精度检测。     

On-Line Diagnostic Tools for CMM Performance

The on-line evaluation of the degradation of a coordinate measuring machine (CMM) performance, either due to variations of environmental factors, or to the deterioration of one of the CMM subsystems, is particularly important for the machine user. A sign of this interest is the large number of international standards that have been issued. The paper presents an approach for the on-line diagnostic of the metrological capabilities of a CMM. The method, which does not make use of additional internal or external instrumentation, is performed on-line during a normal measurement cycle. The graphical approach of the method, based on the use of control charts, permits a simple and immediate monitoring of the machine performance. Preliminary experimental results are presented and discussed.     

Measuring external profiles of porous objects using CMM

Coordinate measuring machine (CMM) has been extensively used in surface measurement and inspection. CMM produces more accurate and reliable results compared with non-contact measurement devices, since CMM measures target surfaces in a tactile way and is not affected by surface reflection quality. However, when there is porosity on the outside surfaces, CMM measurement will have errors because part of the probing stylus will come into the porosity spaces. This paper presents a method of using CMM to measure external profiles of objects with external porosity spaces. The center of a CMM probing stylus will be compensated to avoid porosity spaces and located above external surface areas along surface normal directions. Such a probing strategy can be implemented in both computer-aided design (CAD)-guided mode and non-CAD-guided mode. When the CAD model is available, the probing styli are guided to approach the surface along its normal directions successively to identify and avoid porosity spaces. When the CAD model is unavailable, surface normal directions will be estimated first and then adjusted. The presented method is able to avoid porosity spaces in CMM measurement regardless of the availability of CAD models.     

大型曲面天线精度测试方案综述

以某雷达大型双弯曲曲面天线为对象,提出了大型曲面天线精度测试的几种测量方案。论述了每一种方案的基本原理、数据处理方法和优缺点,对天线的工程测试具有一定的应用价值,同时也适用于一般的大型结构件的测量。     

Wear Measurement and Assessment of Explanted Cross-Linked PE Acetabular Cups Using a CMM

Wear has been considered the main limiting factor in the longevity of hip replacements. Wear analysis is thus essential for determining wear-related failure mechanisms and prediction of wear, which will consequently enable biomedical engineers to improve the design, material, and service life of the bearing components. This article presents wear measurement and assessment of the explanted conventional cross-linked polyethylene (XPE) and second-generation highly cross-linked polyethylene cups (X3) using a coordinate measuring machine (CMM). An expanded uncertainty analysis was performed to assess the performance of wear measurement. Wear measurement using the CMM method was validated with the gravimetric technique. The normalized error between volumetric wear measurement of the CMM method and that of the gravimetric technique was estimated to be always less than 1, suggesting that the CMM method applied to explanted hip wear measurements under the specific conditions was accurate and reliable. The approach to CMM measurement with uncertainty analysis was shown not only to locate 3D wear scar and wear direction but also to accurately quantify linear and volumetric wear with a maximum volumetric uncertainty of ±3.15 mm³ (95% confidence level). It is shown that identifying the key uncertainty components involved in the measurement process including validation, which contributes to an overall expanded uncertainty budget, is crucial to improve the confidence and the reliability of hip wear measurement results using a CMM.