激光焊接原理及实践应用-1.ppt

Introduction 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 Light Amplification by Stimulation of Emitted Radiation 参考资料 References 激光的工业应用-J.F.Ready Industrial Applications of Lasers, J. F. Ready 激光焊接，W.W.Duley Laser Welding, W.W. Duley 激光加工，W.M.Steen 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0.4-0.7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 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) 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) Light and Lasers 激光的聚焦Focusing of Lasers 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