Process automation for welding complex component geometries - Small and flexible tools for good accessibility
In the world of automotive production, everything revolves around efficiency and profitability. Automated welding solutions are the key to optimising production lines and ensuring smooth operations. DALEX GmbH has long been a competent partner for the construction of such systems and has driven numerous innovative developments. One outstanding example is the flexible micro welding guns and push spot welder. They enable, for example, the precise robotic welding of exhaust pipe insulation - and that in the tightest of spaces.
The geometries of components for customised shielding solutions on vehicle exhaust systems vary greatly, as they are optimally adapted to the respective application. The challenge when welding the components lies on the one hand in the low material thickness and on the other hand in reaching all the welding points of the most varied component geometries. DALEX has developed adapted tools for automated welding for this task.
Automation with customised tools
"Due to their fine equipment, our micro welding guns and push spot welder are particularly suitable for welding thin-walled components such as insulating materials, foils in exhaust technology, e.g. on exhaust manifolds, turbochargers, catalytic converters and exhaust pipes, but also for welding contact lugs and cable connections in electrical engineering. Double-sided welding, e.g. for joining insulating shells at parting lines, is the domain of the micro gun. If welding is only possible from one side, e.g. when fastening the shells to the base body of the exhaust line, our push spot welder are used. The fitting geometry can be flexibly adjusted and thus adapts to any component geometry," says Christoph Desch, sales manager at DALEX GmbH.
The micro-welding guns and push spot welder are very light and therefore ideal for use on small robots. Since only a small area is required in the system, space-saving solutions can be realised. At the same time, the welding tools promise optimum accessibility: even in the most confined spaces, all the welding points on the workpiece can be reached without any problems. In addition, the tools can be quickly and easily converted to different components or welding tasks.
Numerous solutions implemented in practice
DALEX offers more than just customised welding tools: its core competencies include above all the design and construction of highly complex manufacturing cells as well as the automation of production processes and has already implemented numerous customer-specific solutions: one example is a flexible robotic welding cell for spot welding various components for exhaust gas aftertreatment. The system is loaded manually via three insertion stations. A handling robot brings the raw parts to the clamping devices. A welding robot joins them together. In order to cope with the complex component geometry and the different tasks, the robot can switch between three different micro welding guns and a push spot welder, which are optimally adapted to the respective task.
At another automotive supplier, several components for exhaust gas aftertreatment were to be automatically flanged and spot welded. DALEX's solution: a turntable welding system with 6 stations for holding the components. The welding is done by two robots: one with micro guns and the other with micro guns and spot welder. Depending on the accessibility of the welding points, the components can be joined with the micro gun or the spot welder.
A robot cell with a 3-station positioner was used for flanging and spot welding heat protection plates on components. A rotary table clamping tool serves as an insertion point for the components. The 3-station positioner rotates them to the two welding robots. To join the sheet metal to the component, the first welding robot sets seven welding spots in succession with a push spot welder and the second sets another four welding spots with a micro gun. A handling robot then transports the component from the welding device to the flanging station.
Christoph Desch: "How complex such systems are depends on the respective task and not least on the component geometries and the accessibility of the individual joining points: For the spot welding and flanging of preformed stainless steel shell plates on exhaust systems, for example, we have built a robot welding cell with 13 robot stations. The components and insulating shells are placed in a clamping device on a tilt-turn positioner. Different robots weld the parts in a continuous process - depending on the accessibility with micro guns or spot welders. To ensure that the component is correctly positioned for the respective points, a handling robot transports it to a total of four component fixtures. The component is then flanged and transferred to the assembly line. Such coordinated solutions enable the user to weld exhaust tract insulation precisely and quickly. Thanks to the high degree of automation and the associated increase in productivity, suppliers can thus confidently meet the global economic pressure."
Further development for even more automation
In order to extend the service life of the micro welding electrodes and save resources, they are reworked with a cap milling cutter. In order to shorten non-productive times and reduce manual activities, DALEX has developed a fully automatic finishing unit for milling the micro-welding electrodes and the push spot welder in cooperation with a milling specialist. The components were optimally matched to each other: The further developed double-stroke guns can pneumatically move to three different positions in order to open wide enough for milling and still maintain the short path for fast welding. If the electrode is worn, the robot-guided clamp opens, moves over the running cap cutter and closes again. In seconds, the electrode is ready for use again and the welding process can be continued immediately.
More flexibility is offered by the optimised spot welder with adjustable holder for robot use and adapter for quick electrode cap change. This allows, for example, reinforcement sheets to be welded quickly and precisely to the frame of a car backrest. To do this, the frame and sheet metal are inserted into a clamping frame. The push spot welder with special electrode cap mounted on the adjustable robot holder then sets seven welding spots in succession.
"So that our customers can see for themselves the performance and flexibility of our micro guns and push spot welders, we have also equipped machines with the tools in our T-Center. Here, for example, we can also carry out test welds and adapt the tools perfectly to the requirements," adds Christoph Desch.
The DALEX micro welding gun (left) and the DALEX push spot welder (right), mounted on robots, are
robots are ideal for joining very complex components in the smallest space.
When joining the components, a robot moves over the individual welding points with micro gun or push spot welder. To adapt the tools to the task at hand, DALEX uses a quick-change system on the robot.
The robotic welding system for welding exhaust tract insulation from DALEX is equipped with a fully automatic rework unit for micro welding guns and push spot welder.
For compact components, the experts at DALEX usually advise using a stationary welding station equipped with a micro welding gun and push spot welder.
Robot cell with two fixed stations, each equipped with DALEX micro welding gun and push spot welder.
In the DALEX Technology Centre, users can test the micro-welding guns and push spot welder at a mobile station.
Photos: DALEX GmbH