Influence of inclined holes in measurement of residual stress by the hole drilling method

The hole drilling method is widely used in measuring residual stress in surfaces. In this method, the inclination of holes is one of the sources of error. This paper presents a finite element analysis of the influence of inclined holes on the uniaxial residual stress field. The error in stress has been found to increase proportionally to the correct inclined angle of the hole. The correction equations by which one may easily obtain the residual stress, taking account of the inclined angle and direction, have been derived. The error of stress due to the inclined hole has been reduced to around 1% using the correction equations.     

一种溶液浓度分布测量方法简介

提出了一种在纹影法的基础上加以改进后能够对溶液的浓度轮廓进行观察与测量的新的显微成像测量方法——暗场纹影法。同时给出了该方法原理性实验的观察结果 ,并与微分干涉显微镜的观察结果进行了对比     

Micro-scale hole profile measurement using rotating wire probe and acoustic emission contact detection

The development of a new probing method to inspect the inner diameter of micro-scale holes is presented in this paper. This was accomplished by contact detection using acoustic emission with a Ø170 μm rotating wire probe tip. Contact is detected when the rotating probe approaches and impacts the hole’s inner surface. The effective diameter of the rotating probe is calibrated by using a high precision grade 0 Mitutoyo gauge block. The wire rotating probe used was fabricated with micro stainless steel wire and micro tubes. The probe’s effective diameter was compensated for in the measurement of the hole. The probe was used to measure the diameter and the roundness of micro-scale holes. Probes used in previous publications have different geometry than the probe in this paper and are used almost exclusively for external dimensions. Micro-scale holes of less than 1.0 mm in diameter and 10 mm in depth are successfully measured and the 3D profile is created accordingly. Also, the out-of-roundness values of each level spacing, 50 μm apart in height, are calculated.     

基于卡尔曼预测的差动共焦轮廓跟踪测量方法

针对轴向扫描式差动共焦测量法(ASDCM)测量轮廓效率低下问题,提出一种基于卡尔曼预测的差动共焦轮廓跟踪测量方法。该方法使用激光差动共焦轴向响应曲线数百纳米量程的线性区间实现了表面连续轮廓高精度线性传感测量,提高了测量效率;同时引入基于卡尔曼预测器的轮廓跟踪原理利用已测轮廓点数据对未测表面预测并跟踪,扩展了线性传感轮廓测量法测量范围。实验结果表明,该方法相对于ASDCM法测量效率提升了8倍,且实现了轮廓PV值大于线性传感测量范围的标准椭圆柱高精度跟踪测量,激光聚变靶丸内轮廓圆度重复测量标准差达3 nm。为精密元器件表面连续轮廓的高精度、快速、无损测量提供了一种高质量方法。     

异型玻璃外廓检测及磨边加工技术的研究

在仿形原理的基础上,提出了一种异型玻璃外廓尺寸的检测方法,通过旋转运动与直线运动结合,将传感器采集信息进行数据处理和坐标变换后,获得待测异型玻璃外廓的尺寸,为外廓磨边加工的进行提供精确的运动轨迹.在此研究基础上,采用基于PC开放式数控方式,实现对异型玻璃外廓检测和磨边加工运动控制,并结合实际应用,从硬件设计、软件设计两个方面介绍了基于翠欧开放式运动控制器的异型玻璃外廓检测及磨边加工系统,最后进行了试验验证.     

Optimization of cutting parameters on drill bit temperature in drilling by Taguchi method

In this study, the optimization of the cutting parameters on drill bit temperature in drilling was performed. Al 7075 work piece and the uncoated and Firex® coated carbide drills in the experimental were used. The optimization of the cutting parameters was evaluated by Taguchi method. The control factors were considered as the cutting speed, feed rate and cutting tool. Taguchi method was used to determining the settings of cutting parameters. The L₁₈ orthogonal array was used in experimental planning. The most significant control factors affected on drill bit temperature measurements was obtained by using analysis of variance (ANOVA). Taguchi design method exhibit a good performance in the optimization of cutting parameters on drill bit temperature measurements. In addition, the empirical equations of drill bit temperatures were derived by using regression analysis. The obtained equations results compared with the drill bit temperature measurement results. The empirical equations results indicated a good agreement with experimental results.     

Fundamental uncertainty analysis of flowrate measurement using the ultrasonic Doppler velocity profile method

The present paper describes a fundamental uncertainty analysis for a flowrate measurement in a pipe using an ultrasonic Doppler velocity profile method and an evaluation of the estimated uncertainty by an actual flow calibration. The uncertainties are estimated for internal factors originating from the measurement equipment; UVP provided by Met-Flow sa. and external factors depending on on-site measurements, such as the inclination angle of the ultrasonic transducer. The relative expanded uncertainty due to internal factors is estimated to be 0.34% with a coverage factor of 2. The relative external uncertainty including external factors is estimated to be from 0.42% to 2.13% depends on the inclination angle of the transducer. The results of the actual flow calibration under the same condition as the uncertainty analysis are within the range of uncertainty considering the internal factors.     

钛合金深孔钻削钻头刀片材料和几何参数的选择

这里以难加工材料钛合金为研究对象，针对钛合金材料的加工难点特性，选择目前国内相应的硬质合金材料，并优化组合出不同的钻头几何参数，进行了深孔钻削试验。通过对试验结果进行分析，确定出适合加工钛合金材料的深孔钻用刀片材料和几何参数。     

两相流速度分布算法的研究

提出一种基于小波变换、神经网络和空间滤波测量速度成像的方法。神经网络用来重构管道相关部分的图像。小波变换用于确定每个像素空间滤波信号的带宽 ,并由此得到速度和它的图像。实验结果表明这种速度成像测量方法是可靠的。     

Influential factors on hardness uniformity of Vickers hardness blocks for high hardness range

Reference Vickers hardness blocks for high hardness range were developed from WC 9–Co and WC 6–Co mixtures by two different processes of powder metallurgy, conventional liquid phase sintering in hydrogen and vacuum-sintering with subsequent hot isostatic pressing in one cycle, sinter-HIP, in order to analyse the appropriateness of the manufacturing process and the influence of starting characteristics of the mixtures on hardness uniformity and overall metrological characteristics. WC powder of 150 nm grain size and 2.5 m²/g specific surface area with the addition of grain grow inhibitors was used as starting material. The emphasis of the research was placed on hardness uniformity of the test surface as it is the most important property placed on hardness blocks. For that purpose the surface of the blocks was divided into radial and circumferential divisions, forming different sections on the block surface. Hardness measurements were performed in each section with HV1 measuring method. A total of 40 indentations were performed, based on which the conclusions about hardness uniformity of Vickers hardness blocks were drawn. Hardness measurements and uniformity were tested by analysis of variance, ANOVA, for single factor in order to determine if significant hardness variations across the block surface were present. From the research conducted it was concluded that hardness distribution across test surfaces of Vickers hardness blocks had a trend according to a process of manufacturing and the amount of binder in the WC–Co mixture. The best material and metrological characteristics were obtained on the block manufactured by sinter-HIP with 9 wt.% Co.     

Evaluating the measurement capability of a wheel profile measurement system by using GR&R

Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. This graph has the advantages that it can visualize three different levels of data quality in same figure, namely “unacceptable”, “acceptable” and “good”, and also include a number of measures without becoming unclear, which are features that have been missing in previous presentations. The results show that the measurements of the flange slope are on an acceptable level, while those for the flange height, flange thickness and tread hollowing have to be rejected as unacceptable. The action proposed for increasing the quality of data on the flange height, flange thickness and tread hollowing is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making. This investigation also shows that there is good reason to be careful when selecting measures and when interpreting the results, since, for a certain wheel profile parameter, when one measure is used, the results may be acceptable, but when another measure is used, the results may be unacceptable.     

由硬度凹坑形貌预测金属材料塑性及切削加工性

测定十种典型金属材料的硬度后,用金相显微镜和JXA-840型电镜观察测硬度时留下的凹坑及其剖面的形貌后发现,塑性及切削加工性不同的金属材料,其凹坑形貌也各有特点,将试验结果列表对比说明,可由铸件或试样的硬度及凹坑形貌预测材料的塑性及切削加工性。     

Quantitative measurement of indentation hardness and modulus of compliant materials by atomic force microscopy

An atomic force microscopy (AFM) based technique is proposed for the characterization of both indentation modulus and hardness of compliant materials. A standard AFM tip is used as an indenter to record force versus indentation curves analogous to those obtained in standard indentation tests. In order to overcome the lack of information about the apex geometry, the proposed technique requires calibration using a set of reference samples whose mechanical properties have been previously characterized by means of an independent technique, such as standard indentation. Due to the selected reference samples, the technique has been demonstrated to allow reliable measurements of indentation modulus and hardness in the range of 0.3-4.0 GPa and 15-250 MPa, respectively.     

圆柱凸轮轮廓的三坐标测量法研究及应用

介绍用三坐标测量机基于等分度测量法完成圆柱凸轮轮廓轨迹的自动测量及程序设计,讨论其实际轮廓面在CAD/CAM中的生成,分析其制造和质量控制方法.     

A note on the three-point method for roundness measurement

This technical note presents two enhancements to three-point method for roundness measurement. They enable measuring a larger bandwidth and also present a logical progression from two-point profile to three-point roundness measurement using the combined method. Simulated profiles with and without step variations are used to demonstrate these improvements.     

数字式通用硬度计

外力经负荷传感器量度后施加于压头,取代砝码-杠杆载荷系统,位移传感器在线测取压痕深度,在机内更换相应的压头,实现硬度计的数字化和通用性,预期可适应硬度的常规检验,准确性更好。     

A force-matching method for quantitative hardness measurements by atomic force microscopy with diamond-tipped sapphire cantilevers

We present a new method to improve the accuracy of force application and hardness measurements in hard surfaces by using low-force (<50 μN) nanoindentation technique with a cube-corner diamond tip mounted on an atomic force microscopy (AFM) sapphire cantilever. A force calibration procedure based on the force-matching method, which explicitly includes the tip geometry and the tip-substrate deformation during calibration, is proposed. A computer algorithm to automate this calibration procedure is also made available. The proposed methodology is verified experimentally by conducting AFM nanoindentations on fused quartz, Si(1 0 0) and a 100-nm-thick film of gold deposited on Si(1 0 0). Comparison of experimental results with finite element simulations and literature data yields excellent agreement. In particular, hardness measurements using AFM nanoindentation in fused quartz show a systematic error less than 2% when applying the force-matching method, as opposed to 37% with the standard protocol. Furthermore, the residual impressions left in the different substrates are examined in detail using non-contact AFM imaging with the same diamond probe. The uncertainty of method to measure the projected area of contact at maximum force due to elastic recovery effects is also discussed.     

DQ50钢的显微组织对硬度的影响

试验研究了DQ50钢显微组织对硬度的影响,以及该钢在不同冷速下得到的显微组织。研究得出该钢适宜的冷速应选为10－60℃／min。     

等距型面孔插削原理及其计算机仿真

借助齿轮啮合原理，推导出加工等距型面孔的插刀刀刃曲线方程；运用相对运动原理，进行了计算机仿真，形象地再现了插刀刀刃加工等距型面孔的包络过程。