车削高精度内外球面的工具

我厂生产的φ1.5×3m等型号的矿用球磨机中,均有一副轴承座和轴承支座是内、外球面相结合的重要零件。由于它们配合的球体大(SR550±0.1),球面粗糙度要求高(R_α1.6～0.2μm),内、外球表面在90°～120°区域内每25×25mm~2面积上接触不少于2点。因此,我们根据零件加工难度较大这一实际困难,专门设计制造了一套内、外合一的球面加工工具。经实际使用证明,该工具不但结构简单、性能良好、操作方便,而且成本低、效率高、应用范围广,特别适用于车削大尺寸,互相匹配的内、外球面。     

道夫筒体铸造工艺的改进

道夫铸件是纺织机械上的关键零件,原浇注系统为底返雨淋,铸件顶部加环形冒口,废品率较高(35～40%),严重影响用户单位的生产。 1.铸件的结构和要求 (1)铸件外形尺寸φ718×1150mm,壁厚15mm,重300kg。 (2)外国为主要加工面,不允许有肉眼可见的孔洞(气孔、夹渣等),     

电工纯铁中性介质保护密封退火

电工纯铁的磁性退火通常是在真空或氢气介质中进行,对许多中小型厂而言,目前还不具备这种条件,这里介绍一种在中性介质中保护密封退火的方法。一、准备工作根据零件的几何尺寸,选用带有密封槽的大小箱子(见图1),建议大箱尺寸为250×250×300mm,小箱尺寸为70×70×120mm。大小箱子均用Cr13型不锈钢制作。箱子表面不允许有氧化皮或其它污物存在。小箱内外表面均要进行喷砂处理。大小箱的焊缝必须致密,以渗水法检查是否漏气。密封槽用石英砂填实。装箱用的填料为干     

STD总线工业CNC系统用于数控纵切自动车床

一、机床的功能及特点 数控纵切自动车床主要用于加工棒料零件,最大加工尺寸为16×80(直径×长度,mm),圆度误差0.008mm,长度公差0.015mm,可车外圆、车端面、切槽(切断)、车锥度、车圆弧,配附件还可钻孔及攻铰螺纹,可加工出圆柱,圆锥及非圆曲线的柱状零件。 数控纵切自动车床各刀架传动示意图如图1。     

大型箱体零件内腔表面的喷丸除锈处理

我厂生产的一种大型变压器油箱为钢板焊接结构,油箱内腔尺寸为1580×1240×2010mm。油箱的清洁度要求很高,在内表面涂1504绝缘漆之前要进行喷丸除锈处理。众所周知,对钢铁零件进行除锈,一般可采用化学方法和机械方法。化学方法对中小型零件较为适宜,对大型零件除单件生产可采用手工打磨之外,一般可采用离心抛丸机和高压风喷丸器在封闭的室内对工件进行除锈处理。这种抛丸或喷丸方法只能对零件毛坯或半成品的外表面进行处理,而对大型箱体类零     

在立车上加工外接圆弧的装置

我厂生产φ3.8×12m水泥磨机中的主要零件中空轴(图1所示),有R240mm的外接直角圆弧,其表面粗糙度要求达Ral2.5mm。根据我厂拥有的机床设备情况,安排在普通双柱立车上进行加工。中空轴的外接直角圆弧虽然比其他部位的技术要求低一些,但加工难度、     

三维测量工业内窥镜的双目光学系统

针对国内工业内窥镜只限于观察,无法满足工件三维尺寸测量的现状,设计了一种探头外径为6 mm并且可以向任意方向弯曲的三维测量工业内窥镜,并介绍了该内窥镜的双目光学系统及镜体内部结构的设计。首先,基于双目立体成像的原理,提出了一种具有双物镜、单图像传感器的新型双目光学系统。其次,根据光学系统的技术要求,设计了内窥镜的头部结构。考虑到一些工件内部结构比较复杂,分别设计了内窥镜的可弯曲结构以及后部操控机构以方便一些精密工件的检测。最后,通过三维图像处理软件对待测物表面两个特征点进行长度测量试验,得到了两个特征点的间距。实验结果表明：待测物表面两个特征点的长度测量误差在±0.2 mm内。该系统基本实现了工业内窥镜的三维测量功能。     

50AE钢制管件调质工艺的改进

我厂生产的某产品上有个关键管件,其内在质量好坏直接影响产品性能和寿命。管件采用50AE-YB481-80钢制造,要求进行调质处理,调质时的几何尺寸:4·95mm(内径)×24mm(外径)×424mm(长度)。工艺流程为:下料→正火→深孔钻→调质→机加工。调质的目的有两个:一是保证零件的使用性能要求;二是要满足内膛电解抛光表面粗糙度的要求。有关热处理方面的技术要求有如下几条:①热处理后零件100%进行硬度检验,达到266~302HBS(27·5~32HRC)。②内外组织均匀一致,为回火索氏体。③工件不得淬裂。1·原热处理工艺长期以来,工厂对50AE钢制管件的调…     

轻便零件箱

我厂过去使用的800mm×700mm×800mm零件箱,有效高度620mm,零件磕碰较严重,为此,我们对零件箱进行了改进,使零件磕碰现象减少。首先降低零件箱高度至500mm(附图),使零件存放量减少,而后又在零件箱     

仪表零件端齿自动分度铣床

仪表零件动、停棘轮的端齿分度糖度直接影响仪表走时精度,该零件难于在仪表通用机床上加工,为此我们设计制造了这台仪表零件端齿自动分度铣床。该机床可实现自动分度铣齿加工,分度精度可达6级,光洁度达▽8,吃刀深度精度和偏心量可控制在±0.01mm内;结构紧凑,操作及维修方便。通过改变分度盘槽齿数(Z_盘),即可加工60×Z盘齿的不同齿数工件,扩大了机床的使用范围。     

High-resolution electron microscopy image simulation on a Cray 1S/2300 computer

High-resolution electron microscopy (HREM) image simulation by the multislice method has been implemented on a Cray 1S/2300 computer, allowing accurate full nonlinear image intensity calculations with possible sampling up to 2ⁿ × 2^m samples of the transmission function (n + m = 20). As examples of applications, images have been obtained from an interface in PbTiO₃ and of a small gold aggregate. HREM image simulation of perfect or faulted crystals can now be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells.     

飞机复杂零件上大量小尺寸导孔的快速视觉检测

设计并实现了一套飞机复杂零件上大量小尺寸导孔的快速视觉检测系统MBMS,对其中的关键技术作了深入研究和讨论。采用将视觉检测与多轴数控运动机构相结合的导孔检测方式,提出了一种系统内外参数精确标定方法;详细讨论了检测程序的生成方法,对检测中导孔的检测顺序进行了规划;针对飞机零件上导孔的成像特征,提出了一种高精度、高稳定性的图像定位技术;最后通过导孔的实际成像与基于虚拟相机技术的理论成像对比分析来得出导孔加工精度的评价。该系统为复杂飞机零件上的大量小尺寸导孔提供了快速有效的数字化检测手段。     

基于序列局部图像的尺寸高精度测量方法

为实现大尺寸机械零件的高精度视觉测量,研究基于序列局部图像的视觉测量方法。首先分析机械零件图像边缘的过渡分布特征,提出边缘像素补偿法,消除实际边缘不能精确定位对测量精度的影响。然后以直线边缘距离测量为原型,提出基于序列局部图像尺寸特征的测量方法：对零件进行微小区域成像,生成在空间上连续的序列局部图像;应用相关系数法和双线性插值法获得相邻序列图像的亚像素级尺寸特征线,从而得到各局部图像的尺寸特征;对这些尺寸进行求和与补偿,得到零件的总体尺寸。实验表明,对常规尺寸零件的单幅图像运用边缘像素补偿法,相对测量误差在0.008%以内;对大尺寸零件应用序列图像测量法,相对测量误差在0.01%以内,具有误差积累小的优点,可用于机械零件的精密自动化测量。     

基于机器视觉的齿轮图像拼接方法研究

基于机器视觉的测量技术现在已经相当成熟,但目前使用机器视觉进行工业零件测量的多为小尺寸零件,对于超出工业相机有效物距的零件的测量较少。应用图像拼接方法,将拍摄到的单个齿轮的多个图像拼接成一个完整的齿轮图像,以便后续进行齿轮的测量。在图像拼接过程中,将SURF特征点检测与FREAK特征描述子相结合,节省了特征匹配的时间,提高了拼接速度;使用两次BFMatcher(暴力匹配)及对称性验证,提高了特征匹配点的质量;对特征匹配点进行多次筛选,保证了变换矩阵的准确性;去除变换矩阵中的缩放和剪切动作,保证了图像只进行刚性变换;采用加权图像融合方法,保证了图像的无缝拼接。经实验和误差分析,结果表明该齿轮拼接技术方法速度快、精度高。     

Light exposure and cell viability in fluorescence microscopy

Test systems for measuring cell viability in optical microscopy (based on colony formation ability or lysosomal integrity) were established and applied to native cells as well as to cells incubated with fluorescence markers or transfected with genes encoding for fluorescent proteins. Human glioblastoma and Chinese hamster ovary cells were irradiated by various light doses, and maximum doses where at least 90% of the cells survived were determined. These tolerable light doses were in the range between 25 J cm^?2 and about 300 J cm^?2 for native cells (corresponding to about 250?3000 s of solar irradiance and depending on the wavelength as well as on the mode of illumination, e.g. epi‐ or total internal reflection illumination) and decreased to values between 50 J cm^?2 and less than 1 J cm^?2 upon application of fluorescent markers, fluorescent proteins or photosensitizers. In high‐resolution wide field or laser scanning microscopy of single cells, typically 10?20 individual cell layers needed for reconstruction of a 3D image could be recorded with tolerable dose values. Tolerable light doses were also maintained in fluorescence microscopy of larger 3D samples, e.g. cell spheroids exposed to structured illumination, but may be exceeded in super‐resolution microscopy based on single molecule detection.     

Devolatilization kinetics of olive leaves with application as a precursor for activated carbon production

The objectives of the study were to investigate the devolatilization kinetics of olive leaves and their utilization as precursors for activated carbon. The devolatilization process was performed using thermogravimetric analysis under nitrogen at heating rates of 10, 15, and 20°C min^?1 with kinetic evaluation by the Coats-Redfern and Horowitz-Metzger methods. Potassium hydroxide activated olive leaves were employed as precursors for the production of activated carbon at 700°C for 60?min. Brunauer–Emmett–Teller and infrared spectroscopy were used for the characterization of texture and chemical properties of activated carbon. The adsorption capacity of fabricated active carbon with 1422?m² g^?1 surface area for methyl orange was characterized and data fitted well with a Langmuir model (R²?=?0.9977). The monolayer adsorption capacity of the activated carbon on methyl orange was 714.86?mg?g^?1 and the kinetics followed a pseudo-second-order model.     

Temperature-dependent electrical resistance of conductive polylactic acid filament for fused deposition modeling

This study characterizes the microstructure and temperature dependence of resistance of two commercially available electrically conductive polylactic acid (PLA) composites for fused deposition modeling (FDM): PLA-carbon black and PLA-graphene. No microstructural changes were observed between the filament and the printed parts; however, the resistivity of the filament was found to drop by four to six times upon FDM. Also, compared to the resistivity of individual extruded wire, the resistivity of the printed parts was found to be up to 1500 times higher for PLA-graphene and up to 300 times higher for PLA-carbon black. The raw PLA-carbon black filament and printed wire showed a positive temperature coefficient of resistance (α) value between ~?0.03 and 0.01 °C^?1, which makes them more suitable for sensor development. The raw PLA-graphene filament and printed wire did not exhibit a significant α, which makes them more suitable for printing wires. However, the parts made with multilayer FDM exhibited a negative or a negligible α up to a certain temperature prior to exhibiting a positive α; further, these α values were significantly lower than those obtained for the filaments before or after extrusion. These findings enable proper selection of commercial conductive FDM filaments for enabling quicker prototyping of electronics and sensors.     

Particulate Matter Generation Properties from Sliding Parts Made of Various Carbonaceous Films

The purpose of this work is to reduce the particulate matter (PM) generation from sliding parts by applying carbonaceous films. We investigate particle generation properties of wear-resistant carbonaceous films in the form of a particle size distribution chart. Using a laser scattering type particle counter, we evaluated the particle generation properties of sliding parts coated with high crystallinity, N⁺-implanted high-crystallinity and low-crystallinity diamond films, diamond-like carbon films deposited by ion beam enhanced deposition using static and dynamic mixing methods, Si₃N₄ silicon nitride, and SUS340C stainless steel. The diamond films showed significantly lower particle generation, especially for large particles, than DLC, Si₃N₄, and SUS340C films owing to lower wear. Particle generation from N⁺-implanted diamond films was greater for small particles than for the other diamond films owing to the wear of the N⁺-implanted layer.     

Small sample parts recognition and localization from unfocused images in precision assembly systems using relative entropy

Recognition and localization of mechanical parts using machine vision is a common approach in precision assembly systems. However, positional inaccuracy in assembly systems often produces unfocused images. Hence, existing methods of part recognition and localization are vulnerable to failure. In this paper, we present a part recognition and localization method, based on relative entropy, which can be applied to small samples. First, a template image is generated based on the contour of the parts and divided into several regions. The intensity distribution of the regions was sampled to generate template features. Then, the captured image is segmented using the Gaussian mixture model and the expectation maximum algorithm to extract the target part in the image. Part features are also generated by sampling the target part image using the template features. Furthermore, an optimization model is established in which the objective function is the sum of the relative entropy between the image features, the template features, and the region matching error correction term. By solving the optimization model, the location of the part can be obtained. The proposed method is compared with the edge and invariant feature-based methods through experiments. The results show that the proposed method has higher robustness and is suitable for the recognition and localization of parts with unfocused images. By using this method, the flexibility and reliability of precision assembly systems can be improved.     

Colorimetric determination of mercury vapor using smartphone camera-based imaging

The smartphone camera presents a convenient, portable, and low-cost innovation in colorimetric measurements. In this paper, a smartphone camera was applied for the colorimetric detection of gaseous elemental mercury, an atmospheric pollutant of concern in environment, and workplace monitoring. A cuprous iodide (CuI)/polystyrene composite was used as the recognition element, which exhibited a reddish color in the presence of Hg⁰. Digital images of the sensing reagent phase were captured by a smartphone camera and were analyzed in red–green–blue color space using ImageJ, an open source image processing program. Parameters for the digital colorimetric sensing including the color values, polymer reagent binder, amount of CuI, exposure time, and Hg⁰ concentration were investigated and optimized. The linear working range of the sensor was from 61 to 270?μg/m³ Hg⁰ with a correlation coefficient of 0.978. The limit of detection is 16?μg/m³ Hg⁰. This method shows the feasibility of applying a smartphone camera for a simple, reliable, and inexpensive colorimetric measurement of Hg⁰ vapor in a gas mixture such as air.