Can humans and machines work together safely, without the need to be separated from each other by safety zones and cages? ZKW Lichtsysteme in Austria shows that they can. Working together on a variety of workpieces on the production lines of the automotive supplier are twelve collaborative robots from ABB along with production employees. This not only saves money, but it also makes efficient production possible.
The production of modern LED lighting systems for premium vehicles is a complex process. For ZKW, a specialist in premium lighting systems and electronics, this process involves numerous operating steps at up to 15 production stations. Many components are so delicate that they require more than one set of hands to assemble them. In addition to this complication, the workpieces must not be damaged during assembly. ZKW Lichtsysteme therefore decided to perform part of its production using a collaborative robot application. The application needs to meet all legal and safety requirements and allow for highly efficient simultaneous work on a workpiece.
A production process in which a robot and a human work directly together is still not something you see every day. Quite often, such cooperation involves the production employee having to leave the work area after an operating step for safety reasons before a robot can continue the job. Whilst this ensures that nobody can get hurt, it also extends production times and blocks the assembly of components where human and machine should work hand in hand. Due to special requirements, such a solution was out of the question at ZKW Lichtsysteme.
Challenge: Position and screw on FlexPrint LED daytime running light strips
Modern lighting systems in vehicles are made up of a multitude of LEDs. Instead of being installed individually, they are commonly pre-produced as a moving strip with multiple LEDs and then mounted in the prefabricated lighting unit in several phases. Produced using FlexPrint technology, the strips used by ZKW for the lighting modules are around 60 centimeters long. With the strips being highly flexible and susceptible to preliminary damage, it makes sense to grasp them with a robot arm and precisely position them on the workpiece, such that an employee can tighten the already correctly positioned part of the strip. That’s how the robot and the human work on the part at the same time.
Development of an in-house gripper and positioning system
For grasping and positioning, ZKW Lichtsysteme developed its own gripper system, which is installed on an ABB collaborative GoFa™ CRB 15000 type robot. The gripper has six “fingers” that grab the LED strips from a holder and move them to the first placement and screwing position. If the LED strip is in the correct position, one of the “fingers” moves to the side so that the employee can insert the screws and tighten them. The electric baton screwdriver communicates with the higher-level PLC, with the sequence controller orchestrating the individual operating steps and movements of the robot. After each successful screwing process is confirmed, the robot moves to the next phase to place the remaining part of the strip in the desired position for tightening.
A challenge was ensuring that the complex gripper system did not compromise the GoFa CRB 15000’s maximum 5kg load capacity. For this reason, the engineers at ZKW Lichtsysteme who developed the gripper opted for a carbon structure. The gripper system was machined, mounted, and aligned by trainees from the internal System Engineering department. In addition, it was important to optimally gage the system in terms of weight, to avoid the generation of any imbalances during rotating movements.
A third-year trainee implemented the teaching of movements and programming of the robot using ABB’s RobotStudio® simulation and programming and SafeMove software. The robot system is also able to switch the tool between a left-hand and right-hand gripper system during production, although this kind of hot swap is performed as seldom as possible to keep things running efficiently. The production step is fully integrated in the PLC controller designed and programmed by ZKW, with the entire installation incorporated in the company’s internal SCADA system.
Second challenge: Screwing applications in confined installation spaces
An additional ABB GoFa CRB 15000 is used on a different production line. Here, screws need to be inserted in a very confined space to fasten a variety of components. In this process, it’s important to ensure that no damage is done to the lighting unit and that the screws are securely and precisely applied in angled spaces and larger cavities. The screw spindle has also been developed by ZKW System Engineering. The screws are fed and separated automatically. Here as well, humans and robots alternate directly at the lighting unit and are often no more than 30 centimeters away from each other.
“The employees in production really enjoy working with the collaborative robots from ABB. During demonstrations, they even have a lot of fun intentionally interrupting the robot path to demonstrate how safe GoFa is,” says Christian Blamauer, Systems Engineering manager at ZKW Lichtsysteme. “I would especially like to highlight the achievements of our trainees. They produced the gripper for the cobot and tackled the programming of the application. This shows how important the training and promotion of young talent is at ZKW Lichtsysteme.”
A smooth experience
As of mid-2023, ZKW Lichtsysteme is the company with the most ABB cobots in use in Austria. “Performance, professionalism, and creativity are especially distinctive at ZKW Lichtsysteme. The introduction, tests and checks were implemented in an exemplary manner. The robots were not only validated as a prototype for a use case but were quickly integrated into industrial manufacturing and series production,” says Dario Stojicic, product area specialist for collaborative robots at ABB Austria, as he describes the joint project.
A major advantage during implementation was the very good cooperation between the special machine engineering team at ZKW and ABB. The development department is on-site, right next to the production facility. Therefore, the feedback from prototype production was able to flow directly into the development process. All the relevant people, including the works council, occupational safety specialists and production managers, were involved in the development at an early stage.
The use of robots is an important building block for ZKW Lichtsysteme in terms of competitiveness. In addition, the cobots relieve employees of monotonous activities so that they can devote themselves to more value-adding tasks. This enables the company to create attractive jobs and secure them in the long term. Thanks to the close and real cooperation between human and machine, ZKW has also found the optimal mix of automation, economy and investment costs and is already working on subsequent projects in which ABB cobots will be used again.
