Laser welding technology and equipment
Laser welding technology >> into the colorful world of laser welding  Laser welding equipment Table 1 Comparison of CO 2 laser and YAG laser Military Tactical Gear,Tactical Gear,Military Gear,Army Gears YangJiang Junxiong Trading & Industry Company Co.,Ltd , https://www.cn-sundo.com
Overview
Laser welding is a high-precision and high-efficiency welding method in which a high-power focused laser beam is used as a heat source and a molten material forms a welded joint.
The application of laser welding began in 1964, but was limited to the welding of small and small parts with small power pulsed solid-state lasers. Since the 1970s, with the advent of kilowatt-class high-power CO 2 lasers, laser deep-fusion welding has developed rapidly. The thickness of laser welding has been increased from a few tenths of a millimeter to 50mm, and has been applied to important sectors such as automobiles, steel, aviation, atomic energy, and electrical electronics. At present, in the application fields of laser processing in the world, the application of laser welding is second only to laser cutting, accounting for about 20.9%.
Laser welding equipment is mainly composed of a laser, a light guiding system, a welding machine and a control system.
Laser
The lasers used for laser welding are mainly CO 2 gas lasers and YAG solid lasers. The advantages and disadvantages of the two are compared as shown in Table 1. Wavelength μm Output power Beam quality Optical fiber transmission Optical component Operational consumption and maintenance CO 2 laser 10.6 Big it is good Not Optical components (ZnSn, CaAs, etc.) that require special materials, expensive Need to consume gas; cleaning the electrode is more troublesome YAG laser 1.06 small Second can Can be made with ordinary optical glass, cheap Simply replace the pump light if necessary for easy maintenance
The most important properties of a laser are output power and beam quality. Considering these two directions, CO 2 lasers have great advantages over YAG lasers. They are the main lasers used in deep-fusion welding. Most of the applications in production are still in the range of 15 to 6 kW, but now the world's largest CO2 laser has reached 50kW. While YAG lasers have had difficulty increasing power for quite some time in the past, the power is generally less than 1 kW for micro-joins of thin parts. However, in recent years, foreign countries have made breakthroughs in the development and production of high-power YAG lasers, with a maximum power of 5 kW, and have already invested in the market. Due to its short wavelength, it is only CO 2 . One-tenth of the laser is good for metal surface absorption and can be transmitted by optical fiber, which greatly simplifies the light guiding system. It is expected that high-power YAG laser welding technology will develop rapidly in the future and become a strong competitor of CO 2 laser welding.
2. Light guiding and focusing system
The light guiding focusing system is composed of a circular polarizer, a beam expander, a mirror or an optical fiber, a focusing mirror, etc., and realizes a function of changing the polarization state, direction, transmitting beam and focusing of the beam. The condition of these optical components has an extremely important influence on the quality of laser welding. Under the action of high-power laser, the optical components, especially the lens performance, will deteriorate and the transmittance will decrease; the thermal lens effect will be produced (the lens is heated and the focal length is shortened); the surface contamination will also increase the transmission loss. Therefore, the quality, maintenance and working condition monitoring of optical components is essential to ensure the quality of the weld.
3. Laser welding machine
Its role is to achieve the relative motion between the beam and the workpiece, complete laser welding, split welding machine and general welding machine. The latter often uses a numerical control system, which has a two-dimensional, two-dimensional welding machine or an articulated laser welding robot.