The energy of the light photon is absorbed by the atoms of ruby crystal and electrons get excited to their higher energy level. When they return back to their ground state they emit a photon of light. This light photon again stimulates the excited electrons of the atom and produces two photons. In the case of simultaneous welding, the laser beam is formed so that it adapts optimally to the component.
For very large molds, you can bring the laser to the tool, even right on the press, yet still generate the most delicate features in a cavity. Perhaps more importantly with pulsed laser technology, the heat-affected zone is much smaller. Conventional TIG welding will generate a HAZ almost 0.100″ deep, while the pulsed laser generates only about 0.008″. This lower-heat process has a major impact on how a repaired mold will hold up over time because the metallurgical properties of the mold material are significantly altered in the heat affected zone . Here’s how today’s pulsed laser welding technology enables all these benefits. To understand how pulsed laser welding works, we spoke with Blair Learn, president, and Wes Wheeler, sales manager, at Alpha Laser .
Frequently, those who have purchased the laser systems find that time, labor, and material savings they realized far outweigh the original purchase price. “Laser welders have made our work so much easier that I could not imagine working without one” is a comment often heard from jewelry manufacturers. An experienced jewelry technician can normally make the transition to manipulating the jewelry item in the laser welding machine within 10 to 15 minutes. One of the key elements in making laser welding applicable to jewelry manufacturing was the development of the “free-moving” concept.
It is widely used in welding structure products such as containers, machinery, electric power, chemical industry, aviation and aerospace. You can separate the laser beam by time and energy, or process multiple beams at the same time, and realize multi-station processing, which provides conditions for more precise welding. It is now common for these systems to perform multiple laser operations, including cutting, welding, drilling and marking, using one machine on a single part or family of parts. During this process, the laser beam melts the material and also creates a deep keyhole with approximately 1.5 times the diameter of the laser beam. This keyhole created by the laser welding process is surrounded by the melt.
The portable handheld laser welding machine will take over the traditional argon arc welding and electric welding technology. Laser welding is often the ideal solution for joining metals that require relatively fast processing speed, low heat input, low heat affected zone and minimal distortion. The good beam quality of kW class fiber lasers coupled with medium to high average powers offer a wide range of laser welding mechanisms from narrow high aspect ratio keyhole welding to shallow wide conduction welding. Low to medium power CW fiber lasers are used for welding a very wide range of thin sheet materials up to 1.5 mm thick at very high speed.
The reflectivity of various metals decreases as the wavelength becomes shorter, and the reflectivity of Ag, Al, Cu to laser light is as high as 90% or more. The reflectivity of various metals to lasers of different wavelengths is shown in Table 1. However, due to the high reflectivity and good thermal conductivity of aluminum alloy and the shielding effect of plasma, some defects will inevitably occur during welding. The processed weldments were subjected to welding process experiments within 24 hours.
It is a versatile process because it is capable of welding carbon steels, stainless steel, HSLA steel, aluminum, and titanium. Due to the high cooling rate, the problem of cracking is there when welding high-carbon steels. It is a very efficient welding process and can be automated with robotics machinery easily. The energy, pulse width frequency and light spot size can be adjusted to achieve different welding effects.
In contrast, the Pulsed Fiber lasers deliver a pulse of energy which is typically ten to twenty times higher than their average power. For example, a laser can have 300 W average power and 6000 W peak power. These lasers are often referred to as Quasi Continuous Wave Fiber Lasers. Depending on the intensity of the laser radiation, laser welding is categorized as heat conduction welding or deep welding. How the model is built determines how much and on what you’ll be able to use it. You can choose from small and compact machines to very large laser welders with a bulkier build.