As a significant next step in its transition from being a rental and equipment supplier to the construction industry to a total welding solutions provider for the whole of the welding industry across Southern Africa, Renttech has invested in the premium welding equipment brand, Kemppi. African Fusion talks to Johan Bester about the reasons for the move.
Click to download and read pdf
Kemppi AX Robotic Welding Systems are specifically designed for MIG/MAG welding. Complete arc welding automation packages for MIG/MAG welding enable significant savings in time and quality benefits.
Since the Bidvest acquisition in 2016, Renttech has been on a transformation path. Previously well known for its rental offering and its robust range of associated equipment for use on construction sites, turnkey projects and routine plant maintenance work, since the Bidvest acquisition Renttech has developed a comprehensive product range well suited to high-end fabrication.
“While we continue to offer rental services for onsite and shutdown work, we have been steadily strengthening our position in the use of advanced welding processes to improve the cost and quality drivers for South African fabricators,” says Johan Bester, welding product manager for Renttech.
“To further foster this goal, we have now invested in one of the best premium welding equipment brands in the world. We are now the sole distributor for Kemppi in South Africa, having just taken over the Kemppi agency. To support the latest high-end Kemppi products, we feel a bit of Renttech muscle is needed behind the brand to get the local exposure it deserves,” Bester tells African Fusion.
“We are sure that the Kemppi product range will help the local fabrication industry to address modern and complex welding challenges and quality demands. The company has embedded decades of collected knowledge and technical ability, welding process management and welding arc optimisation routines into its welding machines and made this easily accessible to welders using advanced welding software,” Bester points out.
Kemppi’s global guiding principle is to continuously enhance the usability and reliability of its products, with local experts as highly skilled partners sharing the company’s expertise with local welders and fabricators. “This closely matches what we at Renttech have been working towards, and we believe South Africa is ready and in need of high-end solutions, especially if these make it easier for welders to achieve the first-time quality we need to raise productivity levels,” says Bester.
He notes that Kemppi recently completed another innovation phase with the release of a new high-end range of welding machines for all common welding processes. “On the new advanced products, the user interfaces are among the best we’ve ever seen – compared to high-end competitors from anywhere in the world.” he says.
Using embedded software called Weld Assist, for example, he says that settings for even complex arc welding processes such as pulsed MIG/MAG welding have been made particularly easy. “If using the Kemppi Master M 358 for pulsed MAG welding, for example, Weld Assist asks the welder to choose the base material being welded, the gas being used, the wire thickness, the welding position, and the travel direction. The software comes back with all the machine parameter options, which can then be selected for use or adjusted if necessary. This takes the guesswork out of setting up a welding machine prior to welding,” he explains.
From a process control point of view, he describes the WiseRoot function embedded into these advanced machines for open-root/backing-free weld preparations. “Traditionally, for water pipes or pressure vessels, for example, this would have to be done using the MMA or TIG processes. But WiseRoot enables this critical weld to be accomplished using the semi-automatic MAG process, with solid,” he notes.
WiseRoot is a modified short-arc process that uses precise real-time voltage monitoring to control short-arc current levels for right-time filler metal droplet release. This results in a stable, smooth, spatter-free and efficient arc that delivers excellent weld-root quality – even if using CO2 gas.
MAG welding with Kemppi’s WiseRoot is significantly faster than stick (MMA) or TIG welding options for root welding, while producing welds of equally high-quality at the very least. “Welding of fixed pipes in any position is possible and, most importantly, WiseRoot is easy to learn and it significantly reduces lack-of-penetration risks,” Bester notes.
WisePenetration is another innovation unique to Kemppi. “Normally in CV MIG/MAG welding, the power to the weld pool will change when the welder changes the stand-off distance between the joint and welding torch. This can affect penetration, result in a lack of fusion, change the weld profile or raise spatter levels.
“WisePenetration prevents the current from dropping down by actively adjusting the wire feed speed. This maintains power levels into the arc at preferred levels and reduces the risks of welding defects. “It also allows the weld preparation volume to be decreased, so fewer passes will be needed to fill the joint, heat input can be reduced, and production rates increased,” Bester explains.
“Across all welding processes, Kemppi has put a lot of effort into controlling the welding arc, by embedding digital arc monitoring and real-time control, for example, which can rapidly react to events in the arc to prevent occurrences such as spatter. Also designed into these advanced machines is software to enable fabricators and welders to easily access the best welding programs and parameters needed to produce better quality welds more productively and economically.
“In every machine it has produced, Kemppi has chased speed and positional capability. It is striving to substitute manual and time consuming processes such as MMA and TIG with more productive semi-automatic processes such as MIG/MAG. And, in our opinion, Kemppi is doing an excellent job of this,” Bester tells African Fusion.
The whole platform, he says, has migrated to this philosophy, from stick welding all the way to advanced synergic MIG welding processes for robotic and automated systems. Even on the TIG welding platforms, Kemppi has included features that make the welder’s life so much easier, particularly when he or she is faced with technically difficult welds,” he adds.
When asked to pick out the key features that make the new Kemppi range stand out, Bester highlights two key areas: the highly sophisticated arc-process control that enhances every aspect of welding performance; and the user interface, which has been carefully put together with welders in mind. “The user interface has been developed to interact with welders and to make their lives much easier. These two features really do set Kemppi apart from other manufacturers, in my opinion,” Bester responds.
And the value proposition? “At the end of the day, it is all about the quality required from the welded product. There are certain welds that are very difficult to do well using traditional welding processes. We are seeing more and more of these with very demanding welding, engineering and fabrication requirements.
“Improvement in productivity and repair rates also come into play, which can quickly justify the additional expense of a premium welding solution. So yes, top of the range Kemppi equipment does come at an increased cost compared to conventional welding solutions but compared to other high-end advanced processing machines in the welding space, it is actually quite affordable,” Johan Bester concludes.
