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Laser Welding 101

Green lasers shooting into the night sky

These days, in order to be marketable, a welder needs to be able to practice a wide variety of welding techniques like, submerged arc, resistance, high-frequency resistance, induction, ultrasonic and electron-beam welding. But today there is a technique that is becoming more popular that can (and very well might) replace all of these aforementioned processes.

Laser welding is a process by which light energy, either visible light or invisible (infrared), is focused, absorbed into materials and converted to thermal energy.

            Twenty years ago laser welding was still in its infancy and was seen as a rare, expensive and even unnecessary process. Today, laser welding has been fine-tuned and is used more widely by some manufacturers who require high-volume, high-quality welds.

However, despite its versatility, its speed and the quality of the welds it produces, many manufacturers are still resistant to adopt laser-welding capabilities. This is largely because of the high initial costs, unfamiliarity with the process and the beliefs of the safety concerns of using lasers.

Benefits of Laser Welding

            The major benefit of lasers is their versatility. They are able to weld in hard-to-reach spots (through the use of mirrors), can handle delicate welds and can adjust the output of energy. Lasers can also weld a wider variety of materials than other processes (Some Israeli doctors are even pioneering the use of laser welding to close wounds! … who knew?)

Laser welding is fast. Through a technique called “keyholing,” the laser is able to not only make deeper penetrations but it can increase the speed of the welding process. By heating a spot above the boiling point, a vaporized hole is formed in the metal. This hole traps 95 percent of the laser’s energy and can reach temperatures as high as 25,000 °C. This not only makes keyholing more efficient, but it creates a molten region on the material that fills in behind the keyhole as the laser beam moves, resulting in welding speeds of hundreds of centimeters per minute.

Keyholing also reduces costs by making thinner welds. Lasers can make a very narrow weld, which is perfect for smaller items that require delicate and more precise welds. Also, because the weld is small and of a higher quality, there is generally no need for finishing, which further reduces costs.

Another cost laser welding avoids is the loss of energy. Lasers provide a more stable power output, even from the onset of the process, so there is little waste of energy. You also don’t need to warm up the laser, so again less energy is wasted in the process.

For those of you who have welded professionally, you know that thermal distortion can crack and ruin welds and can slow your work. However, because of the precision of the laser process (and the fact that the lasers use minimum heat on the materials), almost no thermal distortion occurs during laser welding. This allows you to weld faster and increases the quality of your welds.

Lasers also allow welders and manufacturers to be more innovative because access for the process is required from only one side of the material. This makes many different joint configurations possible and opens doors for welders and manufacturers to innovate joint designs.

Safety Issues

OK, lasers and eyes don’t mix and the idea of welding with lasers is a concern for a lot of industry newcomers – but welding lasers are much more safe than is commonly believed. In face, lasers, if used properly, are no more dangerous than other welding techniques.

Industrial lasers are interlocked to prevent damage to the eye or skin and most are equipped with devices that cover the laser so that the operator, and those nearby, can work normally.

Many lasers can also operate under the control of computers and robots, which removes welders from many of the dangers faced in the average welding workplace.

The bottom line is that laser welding is becoming more common as the process becomes fine-tuned, as welding schools teach laser welding to those entering the workforce, and as manufacturers realize the benefits of laser welding. In order to improve your marketability as a welder you may want to study online tutorials or take a laser-training course (some are quick, one day courses). Either way, industry observers expect rapid growth over the next 15 years in laser welding technology, availability and use.



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