Lasers are devices well-known for their ability to emit beams of light, and though they are available in all sorts of forms today, they were only created as recently as 1960. While some people only think of lasers as sources of light that they can get their cats to chase, many lasers are actually so powerful that they can cut metal. In fact, one of the fastest growing branches of machining is laser cutting. Within laser cutting is a subcategory called laser welding, which is on what this piece will focus. To affect change and weld two or more separate pieces of metal together, laser welding uses laser beams to melt the ends and/or edge areas of the pieces. Because laser welding simply uses laser beams, the process does not require the addition of filter material of any kind. In addition, it can be performed in tubes and in open air settings alike. Laser welding is a popular welding process for a number of reasons. In the petrochemical, military and defense, medical, lab research, electronics and aerospace industries in particular, laser welding is popular because, one, it requires less heat input that most other processes and because, two, it has deep penetration abilities. Also, the laser welding process can be completed rather quickly.
The performance of the laser welding process begins when a programmer selects a focal point to target on the surface of the material being welded. Once the laser is focused, its beam is emitted. To help concentrate the energy beam as it goes on to reach its extremely precise and small focal point, the laser is passed through a focusing lens. When the laser beam hits the surface of the material, it converts into thermal energy and starts to melt the material. As the materials of each piece are melted, they are joined together to become one. As they cool, they fuse permanently. To create the physical and metallurgical results, manufacturers usually operate the laser no more than eight inches away from the material being welded. Note that laser welding can create all kinds of joints, including tee joints, butt joints, edge joints and lap joints. Also, laser welding can create thin, small, narrow or deep welds, all which very rarely experience distortion.
Laser welding, also known as laser beam welding (LBW), can be complete by hand, but it is far more common to automate the process with CNC machines and/or CAD technology. Most often, laser welding employs one of two types of lasers: CO2 gas lasers and solid state lasers, known more technically as neodymium-doped yttrium aluminum garnet lasers. The two different types of lasers work differently, but they are both able to complete laser welding, but laser cutting and laser drilling as well. Similar to CO2 gas lasers are other gas lasers, which use a variety of gas mixtures as lasing mediums. Among the most common gases used to create gas lasers are nitrogen and helium. All gas lasers can operate in both pulsed and continuous mode, using low current, high voltage power sources to supply the energy required to excite the gas mixture that is used as a lasing medium. Typically, CO2 gas laser beams emit a wavelength of 10.6 µm, and they have power outputs reaching around 25 kW. While gas lasers tend to be faster than solid state lasers, they do have some problems with the delivery of their beams to reflective materials such as copper. Often, they require a strict delivery system of a rigid lens and mirror. Solid state lasers work instead using a combination of precisely placed mirrors and an electrical current. The electrical current excites electrons, which join the cause of the laser and convert into energy used in the laser beam. Note that only some solid state lasers can operate in both pulsed and continuous modes; some can only work in pulsed mode. Most solid state lasers operate at wavelengths much shorter than those of gas lasers, to the tune of 1 micrometer. For this reason, any and all personnel operating solid state laser beams must protect themselves from damage to the retina using special screens or wearing special eyewear. Power outputs of solid state lasers vary based on the type of media a laser uses. Ruby lasers, for example, typically emit power levels between 10 and 20 W, while Nd:YAG (neodymium in yttrium aluminum garnet) lasers typically output power between .04 and 6000 W.
Laser welding is less expensive, more earth-friendly and more efficient than its contemporaries. To find out more about how laser welding might benefit your application, or to discuss your specifications with an expert, reach out to one or more of the many excellent laser welding experts we have listed on this page.
Laser Machining Informational Video