车身梁截面库组件的开发

采用组件技术研究开发了车身梁截面库系统,可对现有的车身截面形状进行采集、编辑和管理,可计算截面的结构性能参数,支持对截面的不同方式查询,支持截面形状优化,帮助车身设计者设计和确定符合结构性能要求的车身截面参数和形状。论文介绍了车身梁截面事例库的结构和功能,详细给出了截面参数计算和形状优化的实现方法,最后给出了通过截面形状优化提高车身结构性能的算例。     

基于有效厚度法的铝合金构件有效截面特性计算

由于我国2007年10月发布的《铝合金结构设计规范GB 50429?007》采用有效厚度法计算铝合金构件的有效截面特性,需要进行反复迭代,并且若同时考虑局部屈曲和焊接对构件截面厚度的折减,则计算变得更加复杂,不方便工程应用,因此基于该规范采用VC++.NET开发基于有效厚度法的铝合金构件有效截面特性计算软件. 对于铝合金构件在受轴向力、单向受弯、单向压弯、双向受弯和双向压弯等情况下,该软件实现常用焊接或者挤压成型工字形、槽形、矩形、C形以及带肋矩形截面的有效截面形状自动绘制和截面特性自动计算. 实例表明该软件能够提高铝合金结构设计和计算的效率及准确性,有助于该规范的推广使用.     

激光焊接技术在加工汽车EModule-TCU上的应用与研究

激光焊接是汽车零部件加工过程中不可或缺的技术之一.为了研究如何更好的加工汽车EModule-TCU零部件,提出采用的先进激光焊接技术,并对以S7-300 PLC为控制核心的软-硬件系统结构设计作了具体分析.通过这项技术的应用,实现了无人智能全自动焊接过程,向智能全自动化生产迈出了实质性的一步.     

关于激光焊接工艺的现状与进展分析

作为一种高效率、高精度、低变形的先进焊接方法,激光焊接技术在工业制造中得到越来越广泛的应用。从激光焊接技术的概况谈起,介绍了国内外激光焊接技术的研究现状及其应用,最后对激光焊接技术未来的发展方向进行了展望。     

激光焊接技术的发展探究

激光焊接是这几年发展起来的新型焊接技术,激光焊接技术的应用领域及其广泛,尤其是在工业领域。本文详细阐述了激光焊接技术的内涵,特点,分类等基本内容,并着重对激光焊接技术的应用现状和发展进行了分析。希望能够通过本文,对激光焊接技术的领域有个总体的认识。     

铝合金构件有效截面特性计算软件的研制

我国<铝合金结构设计规范>时于可能出现受压局部屈曲以及焊接铝合金构件有效截面特性的计算采用的.有效厚度法",需要进行迭代计算;采用VC++语言开发了"铝合金构件有效截面特性计算软件",实现了各种压应力分布不均匀系数v和焊接热影响效应下的工字形截面、槽形截面.矩形截面、C形截面以及带肋的矩形截面有效截面的自动生成和截面特性的自动计算.计算算例及实际应用表明,该软件提高了铝合金结构设计计算的效率和准确性,有助于新规范的推广使用.     

有视觉的焊接机器人

焊接机器人工作起来不知疲倦,焊接精确,但是它们不能随着焊接形状的改变快速进行重新编程,因此应用受到限制.而且,即使部件稍稍偏离位置,它们也无法对预先编好程序的指令进行调整.为此,由法国、加拿大、日本的研究小组组成一个联合体,推出了一种名叫“Robokid”的焊接机器人,这种焊接机器人能用激光三角测量法“看”焊缝,并在焊接过程中调整激光焊炬.由法国焊接研究所与加拿大伺服机器人公司、日本Sumikin焊接研究所、法国机械工业技术中心联合开发的Robokid用视觉传感器和     

激光除漆技术在船舶领域的应用

激光除漆技术采用激光为加工工具,在船舶领域中应用不但可获得高质量船用钢清洗表面,还能够大大提高后续的喷涂、焊接等工序质量,具有操作方便、定域性好、绿色环保等优势,易于实现除漆装置的自动化、集成化和智能化清洗。通过综述激光除漆机理与工艺等研究进展,重点阐述激光除漆技术在船舶方面的应用,探讨技术目前存在的问题,为激光技术在船舶除漆的工业应用提供参考,也可推广应用于航空航天、高铁运输等其他领域,具有较高的经济价值和社会意义。     

红外再流焊接技术的概述

一、前言 目前,取代原始手工焊接而发展起来的有高波峰焊接、钎焊、激光焊接和红外再流焊接。波峰焊接已用于一部份电子产品上,但真正用于高密度多层印制板和印制大底板上还存在着不少困难,如搭接、拉尖、热损伤、铜箔脱落和印制板跷曲等现象都是需要解决的。以印制大底板为例;它的外形尺寸为320×220 mm,采用2.54网格,每格内走一条至二条微带线,板内布线点约9000个(即9000根高度为17mm的统接插针)、若采用人工焊接既费时又会出现漏焊虚焊,代之有效的是采用非接触     

聚乙烯管道电熔焊接机设计

介绍了一种实现聚乙烯管道电熔焊接的智能化仪器.以单片机PIC16F877为测控核心,采用交流调压模块DTY-H220D35E、传感技术和模糊PID控制算法实现了焊接电压的控制,并且用环境温度测量值对焊接电压进行补偿;激光条码扫描器自动录入管件参数;EEPROM存储器记录焊接数据;采用传感技术实现管件断路、供电电源超压、供电电源欠压和过流检测.此聚乙烯管道电熔焊接机具有焊接质量高、使用方便和节能等特点.     

Sacrificial layer process with laser-driven release for batchassembly operations

A dry sacrificial layer process is presented in which microstructures fabricated on UV-transparent substrates are released by excimer laser ablation of a polymer sacrificial material using laser light incident from the reverse side of the substrate. We investigate the application of this technique to the batch assembly of hybrid microelectromechanical systems (MEMS) built from parts fabricated on different substrates. Preliminary measurements of initial velocity are presented for nickel test structures released from polyimide sacrificial layers using a KrF excimer laser. At fluences in the range 50-250 mJ/cm ² (i.e., close to the ablation threshold), structures with heights of 100 μm are shown to exhibit initial velocities in the range 15 ms^-1, allowing controlled transfer of parts between substrates. Application of the new assembly method to a MEMS device is demonstrated by assembling arrays of electrostatic wobble motors from component parts fabricated on separate substrates by UV-LIGA processing     

Fabrication of high-aspect-ratio electrode array by combining UV-LIGA with micro electro-discharge machining

In this paper, the combination of UV-LIGA with the Micro electro-discharge machining (Micro-EDM) process was investigated to fabricate high-aspect-ratio electrode array, and an easy and rapid process for fabricating ultra-thick SU-8 microstructures up to millimeter depth was described. First, the modified UV-LIGA process was used to fabricate the copper hole array, and then the hole array electrode was employed as a tool in the Micro-EDM process to fabricate the multiple-tipped electrodes. Electrode array of various shapes have been fabricated by this technique. The aspect ratio is up to 17.65.     

Optimization of laser butt welding parameters based on the orthogonal array with fuzzy logic and desirability approach

This paper presents the study carried out on 3.5 kW cooled slab laser welding of 904 L super austenitic stainless steel. The joints had butts welded with different shielding gases like argon, helium and nitrogen at a constant flow rate. Super austenitic stainless steel (SASS) normally contains high amount of Mo, Cr, Ni, N and Mn. The mechanical properties are controlled to obtain good welded joints. The quality of the joint is evaluated by studying the features of weld bead geometry such as bead width (BW) and depth of penetration (DOP). In this paper, the tensile strength and bead profiles (BW and DOP) of laser welded butt joints made of AISI 904 L SASS are investigated. Taguchi approach is used as statistical design of experiment (DOE) technique for optimizing the selected welding parameters. Fuzzy logic and desirability approach are applied to optimize the input parameters considering multiple output variables simultaneously. Confirmation experiment has also been conducted for both the analyses to validate the optimized parameters.     

An adaptive real-time intelligent seam tracking system

The concept of a real-time seam tracking system for welding automation and the initial design for building a prototype is presented. The Adaptive Real-time Intelligent Seam Tracker (ARTIST) uses a robot held, laser based vision system for automation of arc welding processes, and is currently under development at the Applied Research Laboratory of the Pennsylvania State University. The design of ARTIST builds upon the concept of a zero-pass technique. The 3D information of seam geometry is collected and processed for real-time guidance and control of the welding torch trailing behind the laser based vision sensor. This zero-pass concept eliminates the need for preprogramming of the weld path and thus, potentially enhances the welding cycle time for small batches. The ARTIST is designed to support multipass arc welding and to handle any tack welds which are encountered during the seam welding operation.     

Carbon nanofluids flow behavior in novel composites

Nanocomposite materials have broadened significantly to encompass a large variety of systems, made of distinctly dissimilar components and mixed at the nanometer scale. This rapidly expanding field is generating many exciting new advanced composites with promising properties. However, during the fabrication of nanocomposites, many problems could arise and remain as challenging tasks. One such problem is controlling of the nanofluid flow behavior around the microfiber perform as in case of Resin Transfer Molding (RTM) process because of the high resin viscosity and the low preform permeability. In this paper, a two-dimensional simulation model based on the Eulerian multiphase approach has been performed and solved to investigate and predict the flow characteristics of a carbon nanofluid around a staggered microfiber matrix. ‘The interactions between the microfiber walls and the interfacial nanofluid layers during the flow process have been also studied. Based on the predicted results an energy “imbalance” technique has been applied between the microfiber walls and the interfacial nanofluid layers allowing them the potential to flow more smoothly around the microfiber walls to prevent any potential sticking on the microfiber walls.     

Tracking control system using image sensor for arc welding

A highly accurate and widely applicable tracking control system which guides a welding torch along a joint line is described. The control system includes a servomechanism, a solid-state image sensor, and an image processor. The solid-state image sensor detects the cross-sectional pattern of the welding groove with a He-Ne gas laser. The image processor, consisting mainly of a microcomputer, processes video information and estimates the position of the welding groove center using a statistical technique. This method of tracking control has been employed in the welding apparatus for penstocks with good practical results.     

自动控制在薄板钛合金激光焊接中的应用

采用YAG激光作为焊接热源,针对具有自动控制的激光焊接系统,研究了1.3mm厚的TC4钛合金薄板的双面激光焊接.分析了试样的焊前清洗、保护气体的选择及激光工艺参数(激光功率密度、焊接速度、脉冲宽度、频率等)的匹配对焊缝形成及表观形貌的影响.试验结果表明,施焊前对试样进行合适的清洗十分必要,未经清洗的试样很难实现焊接成功.在保护气体的选择方面,使用氩气的焊接效果明显优于使用氮气;激光功率密度、焊接速度、脉冲宽度和脉冲频率4个参数的合理组合,是实现钛合金薄板焊接的关键因素.     

基于图像识别的AH36钢激光焊缝节点定位技术研究

激光焊接过程中，强光导致焊接节点的视觉图像质量较低，降低了定位准确性。为了优化特殊材质的激光焊接节点定位精准度。以AH36钢为例，设计一种激光焊接节点视觉定位方法。在获取AH36钢的激光焊接节点区域图像后，通过EGDNet算法获取焊接节点边缘图像。利用Shi-Tomasi算法检测焊接边缘图像的角点，计算节点在AH36钢激光焊接图像中的位置坐标，完成AH36钢激光焊接节点定位。实验结果表明，该方法的焊接节点采集质量高、定位精度高、定位效率高。     

一种并联激光焊接机器人的机构设计与运动学分析

提出了一种3 分支5 自由度的并联激光焊接机器人,通过3 个分支共同作用,使整机具备了5 个自由 度的空间加工能力．针对激光焊接,通过分析该机器人的结构特性,建立了其正反解运动学模型,通过解析法求解 该模型并进行了计算仿真．最后,对机器人进行激光拼焊实验,仿真数据和实验结果表明,本文研究的并联机器人 机构适用于实际的高速、高精度激光焊接．     

Novel positive-tone thick photoresist for high aspect ratio microsystem technology

 A methacrylate copolymer combining chemically amplified concept and casting technique was developed as a novel thick photoresist for the UV-LIGA process. Photoresist layers up to 500 μm in thickness can be fabricated easily. Microstructures fabricated by the novel thick photoresist were demonstrated. At present, the ring-shape microstructures with 150 μm tall and 15 μm wide have been realized and the calculated aspect ratio is 10. Received: 10 August 2001/Accepted: 24 September 2001