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.     

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.     

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.     

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.     

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.     

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.     

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.     

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。     

Investigations of new possibilities in the calibration of diamond hardness indenters geometry

The influence of Rockwell and Vickers diamond indenters geometry in hardness measurements justifies the strict specifications and tolerances in the relative standards. Many methods, and consequently dedicated instruments, have been developed to investigate the geometrical parameters in order to calibrate the diamond indenters. Most of them, using contact or contactless methods, can only investigate some profiles of the indenters; from these partial measurements the whole geometry is derived. Few other instruments can investigate the whole shape but, since they are custom-developed, costs and difficulties in the calibration of these instruments have limited their use.A new method is proposed in this paper using a commercial and not dedicated instrument: a 3D measuring confocal microscope. This type of instrument has also the advantage that the whole geometry is analysed with a consequently knowledge improvement in the indenter calibration.In the paper the measurement method, the used instrument and its calibration to assure traceability to the length and angle standards are investigated.     

超音速火焰喷涂WC涂层超高速磨削试验研究

针对超音速火焰喷涂碳化钨涂层存在的加工困难,研究了不同砂轮线速度对涂层磨削力、表面粗糙度及表面微观形貌的影响,试验结果表明,随着砂轮线速度的大幅度提高,涂层磨削力、表面粗糙度值都能得到明显的减小;通过观察磨削表面的微观形貌发现,在超高速磨削条件下,涂层材料的去除方式更多的以塑性去除为主.     

钢厂中型材计量与标牌打印联机运行系统的开发

本文主要阐述了应用串行通讯技术完成中轧秤计量计算机与标牌打印计算机联机运行的方案,实现标牌自动打印,不再需要人工干预。     

基于海流剖面的UUV辅助导航方法

为了解决水下无人航行器(UUV)携带的测速传感器在失效情况下无法正常导航的问题,提出了一种基于海流剖面的UUV辅助导航方法.该方法首先采用实时性较好的卡尔曼滤波技术对海流剖面数据进行滤波,并引入小波变换方法辅助确定卡尔曼滤波器观测噪声方差、根据导航速度的变化动态计算过程激励噪声方差;然后建立海流剖面-导航速度关系数据库,从而反演UUV的导航速度,进而通过船位推算方法实现对UUV的辅助导航.为验证该方法的有效性,分别就海试时多普勒测速仪(DVL)测得的UUV速度数据1/2有效、1/10有效、1/20有效以及长时无效情况下进行计算分析,试验结果表明:在DVL声呐数据间隔有效的情况下,海流剖面辅助导航可以达到UUV的导航精度(CEP＜0.5％)要求;且即使出现DVL声呐长时间得不到有效数据的情况,其导航精度也大大高于单纯使用UUV动力学模型进行辅助导航时的精度,说明海流剖面辅助UUV导航方法研究具有较大的意义.