The automotive supplier Yanfeng Automotive Interiors (YFAI) is a global provider of automotive interior solutions. Headquartered in Shanghai, the company has over 110 locations worldwide, including a production facility in Lüneburg, Lower Saxony. Numerous components such as instrument panels, door panels and armrests are manufactured there. Plant manager Michael Oji: "The automotive industry is undergoing a profound transformation. Against this backdrop, we want to convert our production processes step by step towards Industry 4.0 as part of the future-oriented alignment of our sites."

As a first step, the company decided to integrate a cobot into the production line, which supports employees in screwing together armrests. Specifically, this is an LBR iiwa from Kuka, which was put into operation together with the system integrator Schulz Systemtechnik. In contrast to conventional industrial robots, which are usually not sensitive and therefore stand behind protective fences for safety reasons, cobots do not require complex structural measures. The safety of employees is ensured by joint torque sensors integrated in each of the robot's seven axes. If even one of these sensors senses a vibration, the cobot stops moving immediately. In addition, the robot only has smooth shapes, thus reducing potential hazards for humans.

The safety devices eliminate the rigid separation between fully automated and manual work - the two areas merge. The resulting direct cooperation between humans and robots offers numerous advantages: While humans are very flexible and can adapt quickly to new situations, the robot works with consistent precision. "This enables us to make production processes even more efficient," says Michael Oji. As safety devices such as fences are no longer required, the installation space is correspondingly smaller and flexible production islands are created that can also manufacture different products. Last but not least, the cobot relieves humans of both strenuous and monotonous, repetitive tasks.

Specifically, the task of the HRC robot at Yanfeng is to screw together the armrests of all four doors of the Opel Insigna. To do this, it shares the workspace with two employees. In the first step, the worker prepares the component. To do this, he inserts an injection-molded component together with the leather pad into a machine tool that laminates the two components. The worker then takes the laminated component and clips it to another injection-molded component to complete the arm rests. The next step is carried out by the cobot. To do this, the worker places the component in a holder. By pressing a button, the robot is informed that the machining process can be started. The robot then moves to the holder and screws the two components together. The screws are fed automatically via a hose attached to the protective sleeve. The worker then takes the finished arm supports and stacks them for removal.

Two workers each work on one machine tool in the system. They 'share' the cobot. There are a total of four holders for screwing. This eliminates waiting times.

High load capacity is crucial

The robot at Yanfeng is programmed so that it always chooses the most efficient way to screw the components together as quickly as possible.

© Kuka

One of the decisive factors in Yanfeng's choice of the LBR iiwa lightweight robot was that it can move payloads of up to 14 kilograms. Dennis Rittmann explains: "The robot must be able to guide a screwdriving head weighing 13 kilograms. The robot also has the CE marking required in Europe." An important challenge during commissioning was to ensure the safety of the workers at all times. In addition to the safety devices already provided by the robot, an automatic screwdriving machine from Stöger Automation specially designed for HRC systems ensures safe collaboration. The screwdriving head is mounted behind a protective sleeve. If the sleeve hits an obstacle, the robot switches off immediately.

The system with the cobot has been in operation since December 2017. Initial experiences have been consistently positive, as Michael Oji confirms: "The robot has now paid for itself. What's more, our colleagues have quickly familiarized themselves with it. They are able to operate the robot themselves in the event of an error message and rectify the fault. No separate training was required for the employees to operate the robot." The two workers and the robot complete 45 vehicle sets in one hour. That corresponds to 180 bolted armrests. In the medium term, the company plans to use more cobots in its plants.

The sensitive cobot

Another example of the use of sensitive cobots is the automation of the calibration process for measuring equipment of different sizes at Perschmann Calibration. The calibration service provider from Braunschweig specializes in the calibration of manual measuring equipment, including high-precision testing of gauges such as mandrels and setting rings. According to the ISO 9001 standard, measuring equipment must be calibrated at regular intervals. The company's customer base consists primarily of customers from the classic mechanical engineering, automotive and aircraft construction sectors.