激光精密切割技术在特种雕刻行业中的应用

激光加工是激光应用的主要领域，而激光切割又是激光加工中发展最为成熟、应用最为广泛的一种新技术。本文在简介激光加工材料的物理过程的基础上，分析了我国的激光精密切割技术在雕刻行业中的应用现状及应用前景。     

激光热处理与激光焊接

激光是一种在机械工业中应用前景十分广泛的新型热源.近年来,国外在零件热处理、焊接以及切割等各方面应用得很广,同时越来越显示出独特的优越性.目前,我国机械工业对激光热处理、激光焊接以及切割等方面也进行了大量的研究,并且开始推广应用,取得可喜的成果.本文就激光热处理、激光焊接在机械工业中的应用作一些介绍.     

激光测量技术及其应用

随着现代科技的不断进步，激光技术已渐渐地被人们所接受和认同。激光的应用领域也已十分广泛，几乎涉及到当今科技的各个方面。尤其是在激光加工、激光测量、军事上的应用更是显现出极大的优势与潜力。这里介绍了激光定位传感器原理及其在工业生产中越来越广泛的应用前景。     

激光加工在汽车工业生产中的应用

通过在汽车制造中采用激光加工技术的大量应用实例,说明激光加工技术不仅能保证汽车的加工质量,且加工可靠安全,使制造效率提高明显降低了制造成本。     

激光技术在微电子工艺中的应用

本文介绍了国外在微电子工艺中以激光技术进行激光退火、激光划片、激光焊接、激光微调、激光制造集成电路及其检验等应用的状况。     

钣金工艺中的激光加工技术

1960年世界上第一台激光器问世以来,激光成了20世纪的重大科学发明之一,激光材料加工也成为一种新型的高能束流加工技术。激光单色性、相干性和平行性的三大特点,特别适宜于航空、航天、汽车、造船和冶金工艺的钣金工艺,为材料加工工艺提供了一种理想实用的新手段。如今,激光加工技术已从特殊用途的加工技术变为通用的、具有各种加工能力的精密加工技术,在激光的所有应用领域中,激光材料加工占30％以上。     

激光表面强化技术及其应用

激光表面强化技术至今已有20多年的历史,各方面取得了长足的进步,部分技术已经在工业实际应中取得了显著的效果,但其推广并未达到人们所期望的效果。 本文作者简要论述了激光相变硬化、激光冲击硬化、激光上釉、激光表面合金化及激光熔覆等激光表面强化技术的艺性能以及存在的问题,有助于广大读者对此项技术有一个全面、客观的认识。     

特种加工机床的发展动向：激光加工机应用领域迅速扩大

最近，在工业界起重要技术作用的特种加工机床，包括以激光加工机为主的等离子加工机床，电子束加工机床和水喷射加工机床等。人们对这些高效率，高精度加工技术的期望在日益增大。许多制造厂也在大力开发高效率，廉价的产品。本文对这类机床的技术和市场动向加以介绍     

激光切槽工艺的新发展

激光焊接、切割和金属表面处理早已被人应用,但要把它作为一种金属加工的方法却效果不好,仅在难加工材料加工方面偶而采用。本文介绍一种可用于切槽加工的新方法。     

激光精密加工技术及其应用

介绍了激光和激光精密加工的特点，以及几种激光精密加工技术在工业生产中的应用情况，并指出了激光精密加工技术在工业生产中的发展趋势。     

活性剂等离子弧焊焊接电弧的特性

针对活性剂等离子弧焊焊接过程,采用红外热像伪着色法测定了活性剂等离子弧焊焊接电弧温度场,并建立了活性剂等离子弧焊焊接电弧热流密度径向分布模型,对焊接电弧外形的变化,焊接电弧电压与活性剂之间的关系进行了研究。研究结果表明：活性剂等离子弧焊焊接电弧的温度分布比较紧凑,温度场外形窄,温度分布范围较集中,电弧径向温度梯度较大。电弧径向温度分布呈现正态Gauss分布模式。活性剂等离子弧焊焊接电弧收缩,弧尾翼消失,尾焰加大,电弧穿透力增强,电弧电压升高。     

保护套圈对步进式电弧螺柱焊过程电弧行为的影响

利用自行研制的步进式电弧螺柱焊枪,采用套圈作为焊接过程的保护方式,研究了套圈保护步进式电弧螺柱焊过程。对焊接过程的电流及电压波形进行采集,分析焊接过程的电弧行为。实验结果表明,在套圈保护下,步进式电弧螺柱焊过程电弧稳定燃烧,熔化金属短路现象明显减少;螺柱送进过程的“无弧”时间缩短。焊接过程电弧行为的改善提高了电弧对接头的加热效率;与无保护步进式电弧螺柱焊相比,套圈保护步进式电弧螺柱焊可以在一定范围内缩短焊接时间。     

BASIC THEORY AND APPLICATIONS OF WELDING ARC SPECTRAL INFORMATION

Welding arc spectral information is a rising welding information source.In some occa- sion,it can reflect many physical phenomena of welding process and solve many problems that cannot be done with arc electric information,acoustic information and other arc information.It is of important significance in developing automatic control technique of welding process and other similar process.Many years study work on welding are spectral information of thc anthor are dis- cussed from three aspects of theory,method and application.Basic theory,view and testing methods of welding arc spectral information has been put forward.In application aspects,many applied ex- amples,for example,monitoring of harmful gases in arc(such as hydrogen and nitrogen)with the method of welding arc spectral information;welding arc spectral imaging of the welding pool which is used in automatic seam tracking;controlling of welding droplet transfer with welding arc spectral information and so on,are introduced.Especially,the successful application in real time controlling of welding droplet transfer in pulsed GMAW is introduced too.These application examples show that the welding arc spectral information has great applied significance and development potentiali- ties.These content will play an important role in applying and spreading welding arc spectral infor- mation technology.     

双钨极间接气体保护焊接电弧的数值模拟

间接电弧焊接是一种新型的焊接方法,具有高效、节能、焊接应力和变形小的优点。为了研究间接电弧的电弧参数的分布特点以及这种焊接方法热输入低的根本原因,利用有限元分析软件,建立双钨极间接电弧的三维有限元数学模型,计算得到双钨极间接电弧的温度、等离子体流速、电弧压力以及热流密度分布等特征参数;通过高速摄像拍摄到的电弧形态照片与计算得到的温度云图对比验证模拟结果的可信性。结果表明双钨极间接电弧面对称且向阳极方向偏转,呈上宽下窄的倒钟罩形态,阳极一侧的各项特征参数大于阴极一侧;与惰性气体钨极保护(Tungsten inert gas arc, TIG)焊接和等离子弧焊接相比,双钨极间接电弧被焊接工件不接电极,主要靠热流密度、等离子体流速、电弧压力等参数都比较低的弧柱区端部加热,造成工件焊接热输入低、熔深浅。     

Study on arc characteristics and their influences on weld bead geometry in narrow gap GMAW of 5083 Al-alloy

As an efficient process, narrow gap gas metal arc welding (NG-GMAW) was employed to join thick plates of 5083 Al-alloy. In this paper, arc characteristics in NG-GMAW of 5083 Al-alloy and their influence on the weld bead geometry were studied with synchronous acquisition system for various groove types, welding modes, welding current levels, and swing frequencies. The arc profiles were measured and appear to be entirely different compared with that in bead-on-plate GMAW process, meanwhile the arc size changes with varied welding mode, welding current, and arc swing frequency. Arc characteristics highly affect the weld bead geometrical parameters such as bead width, welding penetration, sidewall penetration, and weld surface concavity. Linear regressions were made between the arc characteristics and the weld bead geometrical parameters both in swing and non-swing arc process. It showed that a negative linear correlation exists between welding penetration and arc length, sidewall penetration, and arc warpage, while a positive linear correlation exists between weld surface concavity and arc warpage in non-swing arc process. In contrast, a non-linear correlation exists among them and the variation tendency remains the same in swing arc process.     

电弧声信号与铝合金MIG焊缝塌陷的相关性

针对铝合金MIG焊过程热积累作用强容易产生焊缝突然塌陷从而导致焊接过程失败的问题,建立电弧声信号传感系统并以焊接电弧声为研究对象,运用小波分析方法研究焊接电弧声信号与焊缝塌陷的相关性。研究表明电弧声信号的能量变化与焊缝塌陷有着明显的对应关系,电弧声总能量随着焊缝开始塌陷而增加,对电弧声进行小波分解发现不同频带有着不同的变化规律。研究结果为铝合金MIG焊实时焊接塌陷缺陷的检测提供一种新型有效的方法。     

基于周期平均值外特性的脉冲MIG焊弧长稳定性研究

通过对脉冲熔化极惰性气体保护(Metal inert gas,MIG)焊脉冲平均电流电压变化率的计算,提出脉冲周期平均值外特性曲线,并对弧焊电源脉冲周期平均值外特性曲线和电弧静态性曲线的动态稳定工作点进行详细分析,得出利用脉冲平均值外特性控制脉冲MIG焊的控制策略。同时运用双闭环控制实现了基于弧压反馈的I/I模式控制数字化弧焊电源,此电源能在送丝速度稳定情况下自适应弧长扰动变化,实现脉冲弧焊过程一脉一滴熔滴过渡。通过弧长阶跃试验表明,脉冲弧焊过程中焊丝熔化速度快速跟踪弧长变化,具有良好的弧长动态调节性能,保持弧长动态稳定,即焊接过程稳定,焊缝成形良好,同时验证了分析过程正确性和设计过程的可行性。     

Effect of laser on the welding process of short-circuiting transfer MIG welding of aluminum alloys

In this paper, the effect of laser on the welding process in metal inert gas (MIG) welding of aluminum alloys was studied exploiting high-speed imaging and welding electrical signals collecting. Bead-on-plate welding experiments were conducted using conventional short-circuiting transfer MIG welding and laser-short-circuiting transfer MIG hybrid welding. The obtained results point out that it took less time to strike the arc in laser-MIG hybrid welding, and the stability of arc striking was increased. When the laser was introduced into the arc atmosphere, the arc was compressed, and the welding energy was more concentrated. The arc cathode spot was fixed to the laser beam impinging spot, so the arc could burn stably. In laser-MIG hybrid welding, the droplet short-circuiting transfer stability and the weld appearance were improved significantly. Moreover, an analysis method of judging droplet transfer stability which bases on statistical techniques was proposed. By this method, it can be concluded that the short-circuiting transfer process became more stable in laser-MIG hybrid welding.     

焊接电弧的控制系统

本文对工业中常用焊接电弧特别是MIG-MAG电弧的控制系统进行了理论分析,并对其中存在的问题进行了讨论。为了改善焊接电弧的行为,提高焊接质量,作者提出一种新的电弧控制法（QH-ARC法）。利用这种控制法,焊接电弧可以在任何类型的外界扰动下或送丝速度大范围快速变化时保持稳定的弧长和最佳的射流过度状态。因而用它可以作为进行程序焊接、脉冲送丝焊接、单旋钮控制的手段。利用这种控制法还可以对焊缝成型、溶深以及热输入量进行闭环控制。     

Multisensor-based monitoring of weld deposition and plate distortion for various torch angles in pulsed MIG welding

Manufacturing companies often fail to maintain good weld quality due to poor arc stability and distortion after welding. Weld quality can be improved by reducing the transverse shrinkage and the angular distortion in butt welding. The welding deposition efficiency is also an important economic factor. In this work, various pulse voltage parameters have been varied along with welding torch angle in pulsed metal inert gas (P-MIG) welding. The experimental results revealed that the peak voltage is the dominant pulse voltage parameter. Various sensors were also used to monitor arc current, arc voltage, arc sound, and also weld temperature. A strong relationship between arc sound (as well as arc power) and transverse distortion (as well as metal deposition) was found to exist in P-MIG welding. The frequency domain features of welding arc sound were also extracted and correlated to the process characteristics.