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YAG Laser

Pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG)

The Nd:YAG laser uses neodymium as the active gain medium, doped into a host crystal of yttrium aluminum garnet. The laser’s simple optical design includes a power supply that drives and controls the flashlamp voltage and allows precise control of peak power and pulse width during the laser pulse using internal optical feedback.

The Nd:YAG laser also offers high peak powers in small laser sizes, which enables welding with large optical spot size.  The pulsed Nd:YAG laser has been around for many decades and was very popular, but today it's outdated technology. I would say it is best suited to spot welding application under 0.5 mm penetration and seam welding heat-sensitive packages.  Lower investment cost, but high usage cost due to low energy efficiency and high rate of consumables using up.

ND:YAG

PEAK POWERS AND PULSE WIDTHS PERFECT FOR MICRO WELDING

With the Nd:YAG laser, the active gain medium is neodymium, which is doped into a host crystal of yttrium aluminum garnet. This solid rod of material is typically 2.5mm ~10mm in diameter and around 100 ~150 mm. long. Micro welding Nd:YAG lasers are optically pumped using flashlamps and typically emit light with a wavelength of 1064 nm, but can be frequency doubled (532 nm, green). The laser’s optical design is relatively simple; its heart is the power supply that drives and controls the flashlamp voltage and allows precise control of peak power and pulse width during the laser pulse using internal optical feedback.

Having excellent pulse control, the Nd:YAG laser also offers high peak power in small laser sizes, which enables welding with large optical spot size. This translates to maximized part fit-up and laser to joint alignment accommodation. An example is a 25 W laser that can provide 6 kW of peak power, sufficient to weld steel and aluminum with a 600 μm spot size.

The pulsed Nd:YAG laser has been around for many decades, is some outdated on technology and economy and has had by far the largest install base till end of 2016. In today’s laser landscape, it is best suited with a lower investment cost to spot welding application for small material like juwelery etc. 

Laser Welding is a welding technology used to join several metal components. A laser produces a beam of high-intensity that is concentrated into one spot. This concentrated heat source enables fine, deep welding and high welding speeds.  

The limitations of traditional pulsed Nd:YAG or the newly developped pulsed QCW are the maximum welding speed, the minimal spot size that can be achieved and the electrical to optical energy conversion efficiency that can be obtained. Ever more applications are demanding a higher precision control, lower heat input and lower electrical energy consumption. Continuous Wave Fiber Laser Welding is a technology that offers those features.