Automatic turntable system from DALEX for WMU -
Spot and projection welding, bonding, testing and marking
Manufacturing ever faster and more cost-effectively while guaranteeing the highest quality - as an automotive supplier, anyone who wants to withstand the enormous competitive pressure must always be looking for new ways to make their production even more economical. Automated processes often bring the desired advantages here. WMU Weser Metall Umformtechnik GmbH relied on the expertise of DALEX GmbH & Co KG for the production of receiving pots and gussets for the automotive industry. The experts from Wissen designed a complex special welding system with a rotary table and robots for automated spot welding, gluing and nut welding of the components, including testing, measuring and marking processes.
Hundreds of thousands of high-quality parts, components and assemblies every day, piece by piece in identical quality - WMU plans and develops production processes for the efficient manufacture of metallic pressed, drawn and stamped parts as well as assemblies for the automotive and consumer goods industries. From the smallest to the largest series, the company from Hannoversch Münden manufactures complex assemblies from stamped parts in its in-house welding centre. High technological standards are mandatory in all areas of production in order to meet the quality requirements of demanding customers. WMU was looking for an automated solution for the production of locating pots and gusset parts, which spot welds and glues the individual parts of the two component types and also welds on round weld nuts. Short cycle times, high quantities and consistently high quality were further points in the specifications.
"Rotary transfer systems are particularly suitable for mass production. Thus, we designed a rotary table with four stations for WMU. In addition to the various welding tasks and the gluing process, we also integrated modern camera and exposure technology for testing and measuring in quality control as well as a marking station for traceability into the fully automated system," says Dr. Henning Grebe, Head of Design at DALEX GmbH & Co KG.
Three times welding, once gluing
The individual parts of the respective components are placed by an operator in both sides of the component fixture of the system, where they are securely clamped or fixed by pneumatic force clamps and magnetic grippers. After a 90° rotation, the rotary table positions the component fixtures with the components on the first welding robot. The robot is equipped with a spot welding gun and the dosing unit for the adhesive.
In order for the system to be able to join the two fixed individual parts, they are first swung apart by a pneumatic movement. Then the robot applies the adhesive to the intended areas by means of the dosing unit. The pneumatic movement then brings the individual parts together again, and the robot-guided spot-welding gun fixes them in place with spot welds. After another 90° rotation, a second robot applies the remaining welding spots to the joined components using robot-guided spot-welding tongs.
Dr. Henning Grebe: "Finally, the round welding nuts have to be attached. For this purpose, the rotary table rotates by 90° again and positions the component fixture in the working area of a handling robot. This then removes the welded components with a gripper and guides them to a C-module for projection welding. There, the round weld nuts are fed through a setting head and welded onto the components."
Tested quality every second
To determine whether the individual parts have been precisely assembled, the automated quality control follows: The handling robot brings the finished components to the measuring station, where state-of-the-art camera technology checks their geometry. If everything is in order, the next step is the marking station. There, sequential numbers are stamped into the components. They guarantee clear identification and traceability - an essential quality feature in the automotive industry. Finally, an outfeed conveyor transports the components out of the system.
"Our automatic turntable system joins the individual parts reliably and precisely within a few seconds. This allows WMU to run its high volumes while delivering the quality that customers in the automotive industry demand," says a delighted Dr. Henning Grebe. "In addition, the rotary table system enables a quick changeover to different components. Due to the specific design, such systems have a very high reuse factor, so that further components from a component family can continue to be manufactured on the system without great effort after the project has been completed."
Photo 1: DALEX developed and designed a complex special welding system for WMU with a turntable and robots for the automated spot welding, gluing and nut welding of components, with subsequent testing, measuring and marking processes.
Photo 2: A 4-station rotary table with component fixtures positions the inserted components to the various processing stations with spot and projection welding, gluing processes and handling operations.
Photo 3: A handling robot guides the component to a DALEX-C module. There, the round weld nuts are fed in and automatically fixed to the component by means of projection welding.
Photos: DALEX GmbH & Co KG