How the application of intelligent MIG technology enables inexperienced welders to achieve consistent, high-quality welds.

May 8, 2017

Productivity is always under the spotlight and welding is a process that is often scrutinised. Depending on the specifics of the application, welding productivity might be increased by adopting fully automated or robotic welding, using semi-automated processes or improving the manual process. Employing welding operatives with higher skill levels can be cost-effective but, in the majority of cases, a better option is to improve the productivity of inexperienced and less-skilled operatives, bearing in mind that improving weld quality and consistency boosts overall productivity by reducing or eliminating the need for post-weld dressing and rework.

Being so versatile, MIG welding is used for an extremely wide range of tasks, including general manufacturing, HVAC and automotive repair, hence MIG welding is a major focus for companies seeking to improve productivity. Manufacturers of welding equipment have developed various means by which inexperienced operatives can improve the consistency and quality of their MIG welding, and this present article looks at the latest short arc technology from ESAB, known as smartMIG or sMIG.

Some years ago, ESAB developed QSET to make MIG welding set-ups easier and to maintain a stable arc under a variety of welding conditions. The new smartMIG technology is the next evolution of QSET, as it makes set-ups even easier and achieves a level of arc stability that surpasses that offered by QSET. Currently the sMIG technology is incorporated in the new Rebel welding machines that can be used on mild steel, stainless steel, chrome-moly or aluminium plate from 1.0 to 12.7 mm thick, with wire diameters from 0.6 to 1.0 mm, delivering 5 to 205 A for MIG welding at a 25 per cent duty cycle while operating from a 230 V single-phase supply (when using a 120 V supply the maximum current is 130A at a 25 per cent duty cycle); sMIG also supports MIG brazing. ESAB will be applying sMIG technology to more short-arc welding machines in the future.

To use sMIG, the operative simply enters the plate thickness and wire diameter via the 4.3-inch colour TFT display; unlike QSET and other systems, there is no need to input the shielding gas. The final step in setting up the welding process is the production of a short test weld. After that, even an inexperienced welder can produce consistent, high-quality welds, and experienced operatives can more easily find the weld's 'sweet spot' and produce welds without having to concentrate as much as they would normally - which means they can remain unstressed and highly productive for longer.

Commercial sensitivity dictates that full details of the sophisticated sMIG control algorithms cannot be published, but it can be stated that the sMIG technology monitors the welding current and voltage and continuously makes small adjustments to the weld parameters to account for variability in the operative's technique, such as torch angle and stick-out length. Experienced operatives who have welded with the sMIG technology say they can hear the arc's superior stability and see the results on the finished weld, which is characterised by an excellent weld bead appearance and minimal spatter.

If they prefer to, experienced operatives can use the 'advanced' mode offered by intuitive and easy to use TFT panel, which enables them to fine-tune the heat input by means of the voltage trim control, thereby altering the bead profile. Inductance can also be altered to further improve arc stability and minimise spatter.  When in 'advanced' mode, the sMIG technology continues to measure welding parameters and make small adjustments to maintain the stable arc, with the operative's fine-tuning having the effect of moving the 'set point' at which sMIG maintains the stable arc.

When developing the smartMIG technology, ESAB's engineers wanted to make it as easy as possible for inexperienced operatives to produce high-quality welds, which meant simplifying the set-up and automatically maintaining a stable arc during the welding. In addition, the engineers recognised that inexperienced operatives, over time, become experienced and the same welding equipment is inevitably used by both inexperienced and skilled operatives. The result is that sMIG requires only the absolute minimum of parameters to be entered during set-up (just plate thickness and wire diameter) and experienced users have the option to enter 'advanced' mode to fine-tune the weld – yet this still retains all of the advantages of sMIG in terms of ease of set-up and automatic arc stabilisation. 

Rebel action shot
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