What Is a Laser Welder?
A laser welder is a specialized laser processing machine used for metal welding and cutting. This technology utilizes a high-energy laser beam to rapidly heat and melt the workpiece, which then solidifies quickly, resulting in minimal distortion after welding. One of the key advantages of laser welding is its speed, which often surpasses traditional welding methods. Moreover, by precisely adjusting the laser’s wavelength, energy density, and beam spot diameter, laser welders are capable of microfabrication.
Common types of lasers used as oscillators in laser welding machines include YAG lasers, CO2 lasers, and fiber lasers. In recent years, disk lasers and semiconductor lasers have also gained popularity. This advanced technology enables the welding of delicate, heat-sensitive components and materials like titanium, which is susceptible to oxidation at high temperatures.
Uses of Laser Welders
Laser welding is a versatile process applicable to a wide range of materials, from large objects such as automobile bodies and frames to relatively small items like molds and even microfabrication of electronic components. The technology covers various applications, including welding metals such as stainless steel, aluminum, and copper. It is also employed for precision tasks like spot welding of electronic components and seam welding for high air tightness.
Principle of Laser Welders
Laser welding machines typically consist of a laser oscillator, optical path, focusing optics, drive system, and shielding gas system.
The laser light generated by the oscillator is directed through optical components like mirrors and optical fibers to the focusing optics. The focusing optics narrow down the beam to an appropriate spot diameter, which is then emitted from the welding head. To prevent oxidation and plasma formation in the irradiated area, assist gases such as argon, helium, and nitrogen are sprayed—this constitutes the shielding gas system. The drive system includes fixtures and positioning stages to secure the workpiece during processing.
Two primary welding methods exist: thermal conduction and deep welding.
- In thermal conduction welding, the laser irradiates the workpiece, generating heat that melts the surface before it cools and solidifies.
- Deep penetration welding delivers high-energy-density laser beams, enabling deeper welds compared to thermal conduction welding.
Each type of laser used for welding has its unique characteristics, and the laser’s wavelength and output power are selected to match the material and welding method.
1. CO2 Laser
CO2 lasers offer high-power Continuous Waves (CW) and possess a wavelength of 10.6 μm, making them the longest-wavelength lasers among commonly used types.
2. YAG Laser
Although YAG lasers are not as powerful as CO2 lasers, they can be transmitted via optical fibers. With a wavelength of 1.06 μm (1063 nm), YAG lasers exhibit high material absorption rates.
3. Fiber Laser
Fiber lasers offer a wide output range and can be transmitted via optical fibers, allowing for compact machine designs.
Advantages of Laser Welding Machines
Laser welding machines deliver high thermal energy with minimal heat-affected zones, resulting in minimal energy loss. This minimizes distortion in the welded area, allowing for deeper and stronger welds.
Additional advantages include:
- Effortless computer control, enabling automation with robotic arms. Robotic arms offer high flexibility, enabling welding in various locations.
- Line welding instead of spot welding, enhances strength and eliminates the need for reinforcement components, thereby reducing weight.
- Ability to weld in ambient air without requiring a vacuum, unlike electron beam welding.
Laser Welding with Tailored Blanks
Tailored blanks involve welding materials before press forming, a technique used for parts like automobile bodies and frames, which require a balance between strength, durability, and weight reduction. Tailored blanks offer the advantage of combining different materials, allowing for cost-effective weight reduction by using high-tensile materials where needed and softer materials where strength is less critical. In addition to material combinations, tailored blanks allow for variations in plate thickness.
However, tailored blanks have the drawback of potentially brittle joints, which can be compensated for by laser welding. Laser welding minimizes material degradation in the weld area, and the weld zone is rapidly quenched by heat, enhancing joint strength in tailored blanks.
Safety Measures When Using Laser Welders
Laser light is a special form of light generated artificially and includes both visible and invisible laser beams. Due to its high power and intensity compared to natural light, laser light can be hazardous to both eyes and skin. Safety precautions include creating protective enclosures to contain laser light, wearing protective glasses and clothing, and following safety guidelines to prevent exposure.