真空吸具在球壳电子束焊接中的应用

分析球壳电子束焊接装夹的特点,运用真空吸具的优点,设计出一种快速、精确可靠的真空吸具辅助装夹系统,解决了长期以来球壳电子束焊接装夹找正难的问题。     

电子束焊接在运输机械传动部件中的应用

简要介绍电子束焊接技术的基本特点,着重分析电子束焊接技术在汽车变速箱、重型卡车桥壳、摩托车传动离合器、工程矿山机械动力换档变速箱离合器以及联合收割机传动轴等方面的应用。     

球形容器的制造(二)

五、球罐的焊接如前所述,球罐制造分为厂内球壳总成及工地组焊附件两部分。球壳受压元件的焊接均在厂内完成。整个球壳由16块球板组成。内中赤道带10块,南北极带各3块,如图12所示。组焊的总原则为先内后外,先纵后环。由于采用大张冷压球板,组装焊缝总长仅105m。焊接工艺方法为内壁手工焊,外壁自动焊,坡口形式为单面V型坡口,见图17。总焊接流程:将球板分别组装成赤道,南、北极带——装焊防变形装置——点固定位焊缝——纵缝外壁预热——内纵缝手工焊——球带组装点固壳体——第一条环缝外预热、内手工焊妥——装另一极带——第二条环缝外预热、内手工焊——外壁纵、环焊缝碳刨清根     

不锈钢真空吸滤网冲压工艺及模具设计

不镑钢真空吸滤网是真空吸滤机的关键零件，它具有网孔小、分布密集、材料冲压性能差等特点，成为国内冲压工艺研究亟待解决的一个难题。本文在大量实践研究的基础上，对真空吸滤网的冲压工艺和模具结构进行了合理的设计，在小批量生产中，获得了较好的使用效果。     

新型管道真空吸污充气机的设计

新型管道真空吸污充气机是将传统管道真空吸污设备和普通打气筒结构巧妙地结合在一起,既能彻底地解决家庭管道、马桶堵塞问题,也能很好地取代普通打气筒实现对各种体育用球、气球、摩托车、自行车、汽车轮胎的充气。该设备具有成本低廉、使用、携带方便、易于存放的特点,是现代城乡家庭必备的工具之一。     

汽车纵梁液压机器人自动焊机设计要点

汽车纵梁自动焊机由两台焊接机器人和左右纵梁的两套装卡装置组成,每套装卡装置由11个垂直装卡和11个水平装卡组成。液压系统的特点是采用蓄能器与手动方向控制阀,采用反变形法解决焊接变形问题。     

湿式制动驱动桥壳环焊缝真空电子束焊接工艺研究

通过对湿式制动驱动桥壳材料的焊接性和焊接结构分析,研究了用真空电子束焊接湿式制动驱动桥壳本体与半轴套管的工艺方法,并对焊接过程中存在的主要问题、焊接接头的力学性能和显微组织进行了分析,确定其最佳工艺参数。结果表明,焊接接头的性能符合国家相关标准且焊后桥壳变形小,耐疲劳性能好,其使用性能完全满足湿式制动驱动桥壳的设计要求。     

熔模真空吸铸新工艺─CLA法

本文介绍了熔模真空吸铸工艺的原理、工艺。其研究结果表明，熔模真空吸铸工艺具有改善铸件质量，提高产品合格率及提高生产效率等优点，是一项具有发展前途的工艺技术。     

熔模真空吸铸新工艺—CLA法

本文介绍了熔模真空吸铸工艺的原理，工艺。其研究结果表明，熔模真空吸铸工艺具有改善铸件质量，提高产品合格率及提高生产效率等优点，是一项具有发展前途的工艺技术。     

基于电子束能量分布控制的异种金属的焊接

在通用真空电子束焊机的基础上配置两对电子束偏转线圈、工控机、多功能数据采集卡、功率放大器以及虚拟仪器软件,构建一个电子束能量分布控制系统.利用该系统可对电子束扫描加热区域的能量密度分配进行离线编辑、计算和预测,并将电子束焊接过程中的三维能量分布实时显示在工控机屏幕上.对铌钛异种合金采用不对称热输入的扫描加热方式进行焊接,获得了铌、钛熔化量相当,焊缝形状对称的焊接接头.     

磁隙式爬壁机器人的研制

大面积钢质表面预处理(如船舶表面除锈、大型储罐表面除漆等)专用的重载爬壁机器人设计,其技术关键是机器人的吸附效应,即吸附可靠、行走灵活。传统的爬壁机器人有两种吸附方式:真空吸盘式(其不适应重载)和磁吸式(其爬壁运行不灵活)。磁隙式爬壁机器人将真空吸盘式与磁吸式相结合,互补增强机器人的吸附效应,其磁隙结构即将磁履接触壁面吸附改为磁块单独安装不与壁面直接接触,通过调节其间隙改变磁隙效应。该机器人质量75 kg,且要重载几十米长的超高压软管和真空管,作业时管内充满水,专用于船舶表面自动化除锈等作业,实现了钢质表面用水作业,即除即干不返锈的目标。介绍爬壁机器人的设计原理、受力分析、磁隙效应和工业试验。应用表明磁隙式爬壁机器人满足了重载作业、灵活行进、吸附可靠的诸项要求。     

一种模块化真空吸附式组合夹具的研制与应用

介绍了一种通用程度高的模块化真空吸附组合夹具的研制与应用,重点说明了夹具模块的结构、相关技术参数的分析与确定。该夹具结构简单、适应性强,通过夹具模块的组合可用于各种不同尺寸的薄壁工件的装夹,且装夹可靠并能保证工件的加工质量。     

多用真空吸具设计

真空吸取是真空技术在起重、吊运、装夹产品设备等方面的一种应用技术。为适应军工生产中的特种型面、特种材料、易燃易爆产品的加工、装配、吊运的需要,研究出一种多用真空吸具。可吸取多个相似型面的产品。     

发动机试验用液氮（液氧）贮箱的研制

论文介绍了一种粉末真空液氮／液氧贮箱,用于承担某液体火箭发动机试验。该低温储存容器采用立式夹套结构。使用珠光砂真空绝热,几何容积6．2m3综合考虑该压力容器工作环境、制造工艺性、安装条件及空间的限制以及维护成本等诸多因素,详细介绍了研制中材质的选择、结构特点以及漏热计算、相关试验等关键技术。     

Note: Development of target changeable palm-top pyroelectric x-ray tube

A target changeable palm-top size x-ray tube was realized using pyroelectric crystal and detachable vacuum flanges. The target metals can be exchanged easily by attaching them on the brass stage with carbon tape. When silver and titanium palates (area: 10 mm(2)) were used as targets, silver Lα and titanium K lines were clearly observed by bombarding electrons on the targets for 90 s. The intensities were the same or higher than those of previously reported pyroelectric x-ray tubes. Chromium, iron, nickel, copper, and zinc K lines in the x-ray tube (stainless steel and brass) disappeared by replacing the brass stage and the stainless steel vacuum flange with a carbon stage and a glass tube, respectively.     

Highly precise and compact ultrahigh vacuum rotary feedthrough

The precision and rigidity of compact ultrahigh vacuum (UHV) rotary feedthroughs were substantially improved by preparing and installing an optimal crossed roller bearing with mounting holes. Since there are mounting holes on both the outer and inner races, the bearing can be mounted directly to rotary and stationary stages without any fixing plates and housing. As a result, it is possible to increase the thickness of the bearing or the size of the rolling elements in the bearing without increasing the distance between the rotating and fixing International Conflat flanges of the UHV rotary feedthrough. Larger rolling elements enhance the rigidity of the UHV rotary feedthrough. Moreover, owing to the structure having integrated inner and outer races and mounting holes, the performance is almost entirely unaffected by the installation of the bearing, allowing for a precise optical encoder to be installed in the compact UHV rotary feedthrough. Using position feedback via a worm gear system driven by a stepper motor and a precise rotary encoder, the actual angle of the compact UHV rotary feedthrough can be controlled with extremely high precision.     

仿生多材料复合增强骨软骨支架的制造及性能研究

针对关节面上大面积骨软骨缺损修复过程中软骨形态恢复和力学环境恢复困难的问题,设计并制造一种新型聚乙二醇(Polyethylene glycol, PEG)/ 聚乳酸(Polylactide, PLA)/ β-磷酸三钙(β-Tricalcium phosphate, β-TCP)仿生多材料复合增强骨软骨支架。基于CT扫描数据重建的羊膝关节模型上进行仿生多材料骨软骨支架的结构设计,包括多孔定制结构和固定桩及仿生结构;以光固化成形技术与真空灌注工艺相结合制造了的多材料复合增强骨软骨支架,确定灌注温度220℃,真空度–0.08～–0.10 Pa。形貌观测表明真空灌注法能使PLA完全充满整个次级管道,力学试验发现复合材料支架的压缩强度(21.25 MPa ± 1.15 MPa)是单管道多孔生物陶瓷支架(9.76 MPa± 0.64 MPa)的2.17倍, PLA固定桩的剪切强度(16.24 MPa±1.85 MPa)是陶瓷固定桩(0.87 MPa±0.14 MPa)的18.7倍。因此,复合PLA的骨软骨支架具有显著的力学增强和固定能力,有望为大面积骨软骨缺损的修复提供新的治疗手段。     

Effect of constraint on fracture behavior of welded 17mn4 and aisi304 steels

In this study, 17Mn4 (P295GH) pressure vessels steel and AISI304 stainless steel were welded with ER309L austenitic consumable. In experimental part of the study, tensile tests were conducted on welded plates and variation of hardness values along specimen was measured. J-integral fracture toughness values were investigated for different crack locations. In order to determine the regions where plastic deformation did not take place due to constraint, uni-axial tensile test was performed on welded tensile specimen after attaching strain gauges. In numerical part of the study, finite element (FE) analyses were conducted by fixing 2-D models precracked on different locations by using ANSYS software. In these models, stress triaxiality and plastic deformation characteristics around crack tip were determined for each crack locations after stress — strain analyses. The limitation on the extension of plastic deformation at diffusion line causes extra increase in stress triaxiality at crack tip.     

Non-optical bimorph-based tapping-mode force sensing method for scanning near-field optical microscopy

A non‐optical bimorph‐based tapping‐mode force sensing method for tip–sample distance control in scanning near‐field optical microscopy is developed. Tapping‐mode force sensing is accomplished by use of a suitable piezoelectric bimorph cantilever, attaching an optical fibre tip to the extremity of the cantilever free end and fixing the guiding portion of the fibre to a stationary part near the tip to decouple it from the cantilever. This method is mainly characterized by the use of a bimorph, which carries out simultaneous excitation and detection of mechanical vibration at its resonance frequency owing to piezoelectric and anti‐piezoelectric effects, resulting in simplicity, compactness, ease of implementation and lack of parasitic optical background. In conjugation with a commercially available SPM controller, tapping‐mode images of various samples, such as gratings, human breast adenocarcinoma cells, red blood cells and a close‐packed layer of 220‐nm polystyrene spheres, have been obtained. Furthermore, topographic and near‐field optical images of a layer of polystyrene spheres have also been taken simultaneously. The results suggest that the tapping‐mode set‐up described here is reliable and sensitive, and shows promise for biological applications.