Advancements in digital controlled power sources are resulting in new welding process variants that can bring fabricators and manufacturers significant opportunities to improve weld quality, consistency and productivity.
According to BOC product manager automation and welding, Peter Kuebler, these new GMAW (MIG/MAG) variants and enhancements provide opportunities for cost savings in material preparation, welding times and post weld finishing, as well as energy consumption.
Kuebler points out that with the shortage of skilled welders, there is a growing need for welding equipment that requires less operator intervention to achieve acceptable weld quality.
"In recent times welding equipment designers have concentrated on harnessing the versatility and energy efficiency of inverter power sources by manipulating their outputs using digital technology," Kuebler told Manufacturers’ Monthly.
"For example, modified short circuit transfer, such as BOC’s coldArc system can significantly reduce the risk of lack of fusion defects by controlling power surges during arc re-ignition after each short circuit.
"This is achieved by continuously monitoring the arc voltage and switching the machine output current precisely at the point of arc re-ignition using a high speed digital processor.
"As material thicknesses decrease with the trend to light weight, higher performance vehicles and components, the system has found extensive application in the automotive industry, particularly for MIG brazing."
Kuebler says that compared with conventional GMAW welding, the use of this technology has resulted in cost reductions related to faster joint completion times, reduced finishing requirements, lower power consumption, and reduced distortion.
"Importantly, these savings assist in maintaining the competitiveness of automotive and sheet metal industries in advanced economies with high labour costs," he said.
"Another significant process variant that has emerged is modified spray transfer for deep penetration and narrow joint geometry, such as forceArc. By monitoring the arc voltage and rapid intervention, it provides a combination of powerful, stable spray transfer with lower heat input and deep penetration without undercut or spatter," Kuebler said.
Ensuring accuracy and tolerances
Accuracy in fabrication and assembly is a continuing issue in many industries where tight tolerances are required.
Leussink Engineering’s demmeler fixturing tables are designed for assembly, testing and welding processes where the maintenance of tight tolerances is critical.
Company director and design engineer, Jason Leussink, explains that the heart of the system is a solid steel block-like work table designed to provide a sturdy platform for mounting weldments with a variety of angles, blocks and accessories.
"With this system of positioning and clamping in any horizontal or vertical plane, making custom welded fixtures is no longer a cumbersome, time consuming challenge," he told Manufacturers’ Monthly.
"During welding, any changes in the fixture that are needed to compensate for weld pull can be made easily."
Leussink points to Trimax Mowing Systems as an example of an industrial company that was using flat tables and moved to demmeler.
This privately owned NZ company designs, develops, manufactures and markets tractor powered grass mowing equipment – in Australia under the brand name Howard Australia.
"By sourcing the demmeler fixturing tables, it gained higher accuracy in all job processes and now uses them right across the board. It is an item used in tooling processes as well as production and welding as it provides flat surfaces and datums everywhere," he said.
"All tooling and checking of production is done on these; as is inspection to see how straight bases are; general level of accuracy is measured in case of misalignment; plus the fixturing tables are used to build spindle mount surfaces.
"These tables are suitable for use in any industry where accurate and rapid assembly methods are required and wherever economic positioning, clamping, tacking and welding are necessary.
"They can be used in car making, farm machinery and defence products construction, container production, gate and handrail manufacture, mining equipment making and food machine manufacture, and even in the production and reworking of non-metallic parts such as those made of wood, plastic or glass."
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