激光焊接原理及实践应用

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,WJM Technologies,Excellence In Material Joining,激光焊接,Lasers Welding,Girish P.Kelkar,Ph.D.,激光,LASER,受激辐射式光频放大器的英文第一个字母的缩写,L,ight,A,mplification by,S,timulation of,E,mitted,R,adiation,参考资料,References,激光的工业应用,-,Industrial Applications of Lasers,J.F.Ready,激光焊接，,Laser Welding,W.W.Duley,激光加工，,Laser Materials Processing,W.M.Steen,AWS,焊接手册，,1-4,AWS Welding Handbooks,1-4,激光加工手册,-,美国激光协会出版,Handbook of Laser Materials Processing,Published by the Laser Institute of America,公开的相关文献,Published literature,请记住,.,Remember.,学习需要积极的参与,Learning requires active participation,不耻下问,Feel free to ask questions,无所顾及地提出个人不同见解,Do not hesitate to present different viewpoints,光,Light,光是一种电磁辐射,Light is electro-magnetic radiation,我们听不到,.,Waves that you cannot hear,可见光的波长在微米之间。,Visible from 0.4-0.7 micron wavelength,波长小于,0.4,微米是紫外线和,X,光,Below 0.4 ultraviolet to x-rays,波长大于,700nm,的光为红外线和微波。,Above 0.7 infra-red to microwaves,0.4 0.7,m m,Visible,Gamma x-ray UV IR Microwave TV Radio,0.01,m,0.001,m,YAG,1 m,光的吸收和颜色,Absorption and Color,物体的颜色来源于它反射的光的波长,Color of an object(wavelength that it reflects),颜色和光的波长是相关联的。,Color is associated with particular wavelength,黑色和白色代表着什么？,What is the meaning of black or white color?,黑色表面吸收了,YAG,光，而白色在反射了大部分光。,Black surface will absorb YAG light while white will reflect most of it,我们为什么需要激光？,Why do we need Lasers?,材料加工需要吸收很强的光。,Absorption for materials processing requires very intense light,高强度的光可以通过激光聚焦成光束获得。,Intensity can be generated by focusing a beam of laser light,普通光不能聚焦成很高的能量密度（或足够小的点）,Ordinary light does not focus down to a high enough power density(or small enough spot size),手持放大镜可以把太阳光聚焦让纸燃烧但是不能把金属融化,Hand-held lens can focus sunlight to set fire to paper but not enough to melt metal,Light and Lasers,单频的（单波长）,Monochromatic(single wavelength),校准的（平行光）,Collimated(parallel),激光,Laser Light,普通光,Ordinary Light,很多波长,Many wavelengths,不平行,Not parallel,Light and Lasers,激光,Laser Light,普通光,Ordinary Light,激光的聚焦,Focusing of Lasers,激光,Laser Light,普通光,Ordinary Light,单频（单波长）和校准（平行）的光可以聚焦成很小的焦点,Monochromatic(single wavelength)and Collimated(parallel)light can be focused to a very small spot,激光的种类,Types of Lasers,激光能量传输,Laser Power Delivery,连续波,Continuous Wave(CW),脉冲,Pulsed,Q-,开关,Q-switched,激光频率,Laser Frequencies,基频,和倍频,Fundamental and multiples,连续光纤激光,Continuous Wave Fiber Lasers,激光在光纤中产生,Laser light is created in the fiber,可在连续波和脉冲波中使用,Can be used in pulsed mode as well as CW,可以被用于焊接和切割,Can be used for welding and cutting,激光二极管光,Laser Diode Light,激光二极管光,Laser Diode Light,光纤,Fiber,脉冲,YAG,激光（焊接）,Pulsed YAG Lasers(Welding),闪光灯开关产生脉冲,Flash lamp turns on and off to create pulses,光纤用于传送激光,Fiber is used to transmit laser light,闪光灯（光泵）,Flash Lamp(Optical Pump),全反镜,100%mirror,90%,反镜,90%mirror,光纤,Fiber,激光棒,Laser Rod,脉冲打标激光,Pulsed Marking Lasers,Q-switching produces very short pulses,10-100 nano-sec,Cannot be used for welding,Laser light delivered directly;no fiber,Frequency can be doubled or tripled to get green or UV light,M,M,Rod,Mirrors,Q-switch,Galvo Mirrors,Focus,Lens,Frequency Multiplier,(not present in all markers),Galvo-,光学器件,Galvo-Optics,经常用于打标。,Often used for marking applications,逐渐受到焊接应用的青睐。,Is gaining popularity for welding applications,Nutfield,Inc.,Laser,WJM Technologies,激光频率,Laser Frequencies,上表只包括了大部分常用的和商业化的激光器。,Table includes only the most common and commercialized lasers,。,波长,Wavelength Range,激光种类,Laser,频率,Frequencies,(,m,m),远红外,Far IR,CO,2,10.64,近红外,Near IR,Nd:YAG,1.064,可见光,Visible,Frequency doubled YAG,Copper-Vapor Lasers,0.532,0.510,紫外光,UV,Frequency tripled YAG,Frequency quadrupled YAG,Excimer,0.354,0.266,0.15-0.35,脉冲,YAG,激光焊接典型示意图,Typical Layout for Pulsed YAG Welding Lasers,镀膜反光镜,Coated Mirrors,激光,Laser,光纤,Optical Fiber,聚光头,Focus,Head,工件,Work piece,透镜,Lens,注：某些激光不通过光纤直接传输。,Note:Some lasers are delivered direct without fiber,聚焦高度和焦点尺寸,Focus height and spot size,短焦距透镜将光束聚焦成更小的点。,Short focal length lens(of given diameter)will focus the beam to a smaller spot,高的能量密度。,Higher energy density,Focus height is critical due to shallow depth of focus,Lens protection from work piece spatter is important,短焦距,Short Focal Length,长焦距,Long Focal Length,Depth of Focus,Spot Size,Time Share,A single laser can be used for multiple applications on a time shared basis,基于同一个理论,单雷射可以一次性用于多种应用,.,Most convenient with transmission through optical fiber,通过可见纤维的转换是最方便的,.,Processing stations can be in different rooms,工作台可以放在不同的房间,.,Mirrors(100%Reflective),全反镜,Energy Share,Laser energy split into multiple fragments,雷射能量分成多个部分,Typically three outputs for circumferential spot welding,典型的是圆周点焊接的,3,份输出量,Mirrors(Partially Reflective),反光镜,(,部分反光,),33%50%100%,30 W,10 W 10 W 10 W,Total Internal Reflection,完全内反射,Light propagation through fibers depends on total internal reflection,通过光纤的光线传播完全取决于完全内反射,Air,空气,Glass,玻璃,Core,核,Cladding,覆层,Protective Sheath,接地屏蔽,Optical Fibers,光学纤维,Single mode has very small core diameter,10 microns,单模式只有