Initial situation in the project: aluminum door production with KUKA robot

This project involves a customer who manufactures high-quality aluminum gates. In particular, these gates are custom-made to order and their dimensions can vary greatly. Lasaco was therefore asked for a welding system including a flexible welding fixture so that door sizes between 2 and 15 meters long and with a height between 1 and 2.50 meters can be welded automatically.

The challenge of a flexible welding fixture

LASACO has a lot of experience in the automation of welding systems using industrial robots and relies, among other things, on the high-quality welding robots from KUKA for the implementation of such projects. In the case of this particular customer, a special challenge arose, as he needed an individual fixture for flexible welding work. We developed the fixture exactly according to the customer's specifications. The operating personnel are now able to insert all the individual parts of the aluminum door and fix them pneumatically. The welding robot does the rest. The flexible adjustment options enable the customer to manufacture a wide range of diverse product variations, which can also be adapted to future changes in component geometry.

System configuration of the KUKA KRC16-2 industrial robots:

To achieve the longest possible reach, two Kuka KRC16-2 welding robots were used. These were mounted on two linear axes, 15 and 17.5 m long respectively, allowing maximum use of their reach within the specified parameters. They were set up parallel to both sides of the fixture. The power supply was realized with reliable Fronius TPS4000 power sources, which are excellently suited for welding aluminum thanks to their integrated push-pull system. The risk of material distortion is significantly reduced by this system.

In addition to the welding technology, the industrial robot has a magazine that is also mounted on the linear axis and always moves with it. This allows the muntins to be automatically placed in the desired positions in the door frame and welded directly. To compensate for component tolerances, tactile sensors on the industrial robot detect the positions of the struts and frame profiles and calculate the automatic correction of the welding process.

Transmission of the gate data to the welding robot:

Separate design data are available for each door. The parameters relevant for the welding robot are extracted from this and transferred to the system in the form of an Excel file. The somewhat unusual form of the Excel spreadsheet was chosen because the industrial robot has to process 120 different parameters for door production. In addition to the door length and height, these include values such as strut distances, dimensions of profiles and much more. The so-called master robot transfers the parameters to the subordinate slave robot. Based on the data, all welding positions are calculated fully automatically and the welding process can begin. The operating personnel only have to pay attention to the correct positioning of the linear guides, which are specified in the design drawing. Both industrial robots divide up the welding tasks in such a way that they utilize the ideal position, thus reducing the time required. The complete aluminum door is then removed from the system by a crane, while the operator can already insert the raw parts for the following job. For additional welding work on small parts and so-called uprights, another manual turntable with two stations was integrated into the robot system.

Continuous optimization of quality and productivity

Lasaco supervises the further development of the production line even after delivery to the customer. Experience values from ongoing production and other optimization potential are constantly incorporated into the evaluation process. This allows the industrial robot to be continuously optimized, which has a positive effect on the quality and productivity of the entire plant.

For example, an automatic TCP torch measurement system has now been retrofitted to improve the ongoing accuracy of the weld seams. As a result of the optimizations made to the programs over time, Lasaco was able to almost halve the cycle time of the work passes for the customer. The output of the production line increased accordingly. Further options, such as automatic fixture adjustment, are available for future optimizations.

Highlights of the project KUKA welding robot for aluminum gates

  • Welding device individually developed by Lasaco according to customer requirements, with which a wide variety of formats can be realized.

  • Automatic creation of Excel tables from the design data of the gates for further use by the welding robot.

  • Data import of 120 different parameters for exact definition of the gate to be welded with maximum flexibility.

  • Compensation of tolerances and distortion in the material by tactile sensors.

  • 17.5 m linear track for master robot; 15 m linear track for slave robot.

  • Automatic welding torch measurement using the TCP method.

  • Additional rotary table for manual welding of small parts and uprights with two stations.-

Project gallery aluminum gate Kuka welding robot:

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