螺纹的综合测量和单项测量

简要介绍了螺纹测量的现状和目前存在的问题,讨论了螺纹测量需要研究的几个问题,分析了螺纹单项参数测量和综合测量的关系以及螺纹量值传递技术.具体介绍了实现内螺纹中径参数测量的测量原理、测量方法和测量中的问题.     

接触扫描法测量圆柱螺纹量规中径的测量不确定度评定

依据JJF 1345-2012《圆柱螺纹量规校准规范》和GB/T 28703-2012《圆柱螺纹检测方法》,圆柱螺纹量规可用二维螺纹量规扫描仪进行多参数自动测量,其测量方法为接触扫描法。即通过测针沿被测螺纹轴向剖面轮廓进行二维接触扫描,获取被测螺纹轴向剖面轮廓的二维坐标信息,由计算软件算出被测螺纹各参数的测得值。针对用接触扫描法测量的圆柱螺纹量规中径,建立测量模型,分析主要测量不确定度来源,对中径测量的不确定度进行合理的评估。     

基于图像处理技术的螺纹几何参数测量

针对螺纹几何参数测量过程中,传统人工测量效率低、仪器昂贵、耗时费力、偶伴有人为误差等不足.本研究采用非接触测量的方法,利用计算机视觉的图像处理技术,通过系统标定、图像采集、图像预处理、边缘检测、几何参数计算等步骤,实现了对螺纹几何参数的自动测量.通过大量实验证明,该系统具有快捷高效、数据可靠、易于操作、替代传统人工操作...     

批量生产中圆锥管螺纹量规的测量

圆锥管螺纹塞规是一种检测工件内螺纹的综合量规,ISO 7/2规定了这种量规的结构形式和螺纹各参数值。为解决该量规在批量生产中对基面大、中径及锥度的测量需要,我们采用了专用检具测量其各参数的方法及合理的生产检测工艺,本文对此作一介绍。     

自制卡具改进三针测量螺纹中径尺寸

正在螺纹的3个直径(大、中、小径)参数中,中径的实际尺寸对螺纹结合时的互换性、旋合性和足够的连接强度影响是主要的,它决定了螺纹结合时的配合性质,是检验精密螺纹是否合格的一个重要指标。用三针法测量较精密螺纹单一中径是最常用的方法,但是用三针测量螺纹中径尺寸时,三针不容易固定,易造成测量数据不准确。为能方便、快捷、准确地用三针测量螺纹中径尺寸,经过多次研究,笔者设计出了一个可代替人手支撑三针来完成对螺纹中径尺寸测量的夹具。     

基于线结构激光的滚柱表面参数测量系统

为实现行星滚柱丝杠的滚柱表面参数测量,建立基于线结构激光的测量系统,针对滚柱螺纹牙型角、螺距和牙型高等表面参数的测量方法进行研究。首先,根据线激光三角法的测量原理,设计搭建测量装置系统。激光经成像系统,通过CCD摄像头获取到线激光条纹图像,对其进行预处理并提取出激光条纹中心。其次,根据螺纹形状特点对获取的螺纹轮廓进行ROI提取,将轮廓线分段进行处理,简化处理难度并获取不同的表面信息参数。最后,根据提取出的分段利用曲线拟合、特征点提取等方法计算所有滚柱表面参数。经实验验证:该文提出的测量系统对牙型角的测量重复性达到0.6°,螺距测量的重复性达到15μm,牙型高测量的重复性达到8μm,基本达到滚柱表面参数测量的要求。     

石油管螺纹单项参数测量仪使用注意事项

石油管螺纹单项参数测量仪是广泛应用于石油行业的特种精密测量仪器，主要用于测量套管、油管、输送管、钻杆等管螺纹的单项几何准确度，．检测人员可以依据美国石油协会API5B及5D等国际通用标准．通过更换相应规格的测量头或标准块进行石油管螺纹单项参数的检验，、     

扫描法外螺纹中径测量不确定度评定及En值验证

正一、测量方法依据JJF1345-2012《圆柱螺纹量规校准规范》和GB/T28703-2012《圆柱螺纹检测方法》,使用XP16060型螺纹扫描仪对规格为M24-6H的螺纹塞规进行测量。其测量及数据处理方法为:根据螺纹塞规的大小选择合适的测针并进行标定,接着标定主标准器,然后根据螺纹塞规的大小选择合适的光面标准塞规进行标定。标定结束后,在程序中选择与螺纹塞规规格一致的标准,点击仪器开始测量,     

螺纹精密跨线测量的计算方法

本文根据螺纹跨线测量精确公式导出10种实用公式(推导略),不但适于现场应用,还可以解出各种特性参数。     

【测量应用】使用SJ5100高精度光栅测长机测量锥螺纹量规基准面中径

正如何在测长机上非常准确地进行锥螺纹量规的基准面中径测量,是目前国内外测长机的一道难题,中图仪器SJ5100高精度光栅测长机针对此应用进行了独特设计及算法优化,较好地解决了这个难题。锥螺纹基准面中径测量锥螺纹基准面中径是所有锥螺纹量规最重要的一项参数,在未出现螺纹综合测量仪之前,所有锥螺纹量规均采用此项参数作为是否合格的评判指标。传统测量锥螺纹基准面中径主要采用三针法,如     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.