African Fusion July 2023

system for welding, cutting and cleaning

Laser controls include wire feed rate and wire weave width, laser power percentage, spot width and laser pulsing parameters. with a safety-interlock, which automatedly turns off the laser power as soon as the gun breaks contact with the workpiece being welded. Pretorius explains: “Although it doesn’t really need it, the system will not work unless an earth lead is connected to the plate. In addition, the system is designed so the torch must be electrically connected to the workpiece before the la ser can be activated,” Pretorius explains. “The welding torch has a contact arm underneath it that the welder drags along the plate surface in front of the joint. The laser beam doing the welding will switch off the instant electrical contact between the arm on the torch and the workpiece is broken. This removes any risk of the beam being shone at anything apart from the metal plate being welded,” he adds. The contact arm also makes welding easier than traditional TIG, MIG or MMA welding processes, in that there is no need for the welder to control the standoff distance between the torch and the work piece. “The welding beam is very narrow, and while this is ideal for line-welding some autogenous joints on thin plate, the fit-up has to be very good. To ensure that no part of the joint is missed, the spot size of the laser can be increased or the beam weave function can be used. It also helps when wire is being fed into the joint at the same time,” says Cosmo Group’s Petrus Pretorius. In terms of machine settings, he says there is nothing complicated to worry about. “As with all welding, the input power – set as a percentage laser power – is the main parameter, along with the wire feed rate. And as well as the spot size and weave functions, there are numerous other ‘fine’ settings such as sloping start and stop features. “We are just beginning to get comfort able with the new process, though, and it will take time to learn how to weld most effectively with this system,” he adds.

The hand held laser torch brings laser welding with wire feed into ordinary jobbing shops.

The cost? “It is no more expensive than a high-end MIG/MAG or pulsed TIG system,” Pretorius responds, adding that hand held laser welding could result in many cost sav ing advantage. These include: • The welding speeds can be many times faster than other processes, due to the highly concentrated laser energy source. This can significantly raise production efficiency. • The low overall heat input from the concentrated beam makes lasers ideal for joining thin, delicate parts with much less heat distortion. “Fit up must be right, though,” Pretorius emphasises. • Laser welds can be accurate with high quality and seldom need any post weld cleaning. • The system is small and portable, so it can be moved from job to job inside a workshop. • It is suitable for welding a wide range of different materials, including steels and stainless steels, aluminium, copper and many more. • It can also be used to join dissimilar materials, providing a filler material compatible with both materials being welded can be found. As well as the hand-held laser welding capability, the system can also do hand held laser cutting – for tube and plate – and hand held cleaning: “And these functions are activated simply by changing the torch nozzle and lens. “The laser cutting function can deliver good cut quality on any thin ma terials, while the cleaning function is ideal for cleaning rusted plate prior to welding, for example. “This system is potentially revolution ary. It brings laser welding, which used to be reserved for highly specialised work

The remote control for the laser settings.

Hand held laser welding is ideally suited to welding thinner sections in a wide range of different materials, including steels and stainless steels, aluminium, copper and many more. shops and for welding very high-value components, into ordinary jobbing shops. For anyone looking to upgrade their weld ing operations or to expand what they can offer to South African customers, this 3-in-1 laser welding, cutting and cleaning machine might be an ideal solution,” Petrus Pretorius concludes. cosmogroupsa.co.za

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July 2023

AFRICAN FUSION