The aerospace division of Singapore-based ST Engineering Aerospace Ltd - a specialist in aircraft conversion - relies on the support of a robot cell. The company has been working with Helios Applied Systems, also based in Singapore, since 2019 to automate such complex processes.

The robot cell drills dozens of holes in the floor grilles of Boeing's 767-300ER aircraft at the Paya Lebah plant. To do this, the robot cell moves along the floor structure so that the robot can drill the corresponding holes according to a predefined plan. It is located in a hall that is conveniently directly adjacent to the converted aircraft. The robot cell consists of a hydraulically liftable, movable platform, a Yaskawa robot with a payload of 180 kilograms, an end-of-arm tool with a special image processing system developed by Helios and a motor spindle with 6 kW power as well as a hollow shank taper holder for automatic tool changes.

A spindle makes all the difference

The most important prerequisite for choosing the right spindle, in addition to parameters such as concentricity and high speeds, was the ability to easily adapt the spindle to the existing robot using robot changing units. Helios found what it was looking for with the automation specialist Zimmer Group from Rheinau in Germany. The company has 13 subsidiaries worldwide - three of which are also in Asia.

The Zimmer Group supplied Helios with an air-cooled spindle from the HF145-001 series, which has an output of 6 kW and a maximum speed of 24,000 rpm, complete with EtherCAT operating terminal, all necessary cables and a matching frequency inverter. This is particularly suitable for precise positioning tasks with integrated safety technology (STO) and for operations at low or high speeds.

In addition, the inverter offers optimum performance and power yield with perfect coordination of the spindle and frequency inverter. In order to be more flexible for future applications, the spindle was mounted directly on a robot changer unit (WWS100F-001/WWWS100L-001) - also from the Zimmer Group.

This robot exchange unit allows the motor spindle to be exchanged for another tool or handling unit, thereby enabling multiple use of a robot. The Zimmer Group also supplied a storage station for the tool holder. The HSK holders and tools themselves were provided on site by Helios. Helios uses the Zimmer spindle with a fieldbus connection (EtherCAT) and also received the complete parameterization from the Rheinau automation experts. They also provided Helios with comprehensive support for the products and software issues during and after installation.

Successful collaboration

"Due to the rigid construction and the very smooth running of the spindle, even at higher speeds, the drilling result is very good. You have to bear in mind that these parts are light and not completely flat, so the vision system recognizes the position and angle of each hole," says Sunil Raibagi, project manager and Vice President Business Development and Strategy at the Zimmer Group.

The customer Helios is also satisfied: "We value the Zimmer Group as a long-standing partner and are absolutely convinced of the qualities of the spindle. We were also particularly impressed with the service provided by the Zimmer Group, who were always on hand to help us throughout the installation," says Managing Director Shyi-Herng Kan.

Busy in the future

While the robot is currently focused on drilling floor grids, the ST Engineering team is working with Helios to program the machine so that it can also be used to set countersunk rivets. "We believe the robots can handle these types of processes well," said Hui Fung Lee, SVP and Head of Innovation and Continuous Improvement at ST Engineering Aerospace in an interview with cargo facts magazine.

In the coming months, the robot will also be programmed at ST Engineering for other functions and to work on other aircraft models, including the conversion of Airbus freighters. "We know that the P2F process is very complex and that many people are needed for the entire changeover process," explains Lee. "Therefore, we are constantly looking for ways to improve our productivity," Lee continues. Tasks that are suitable for automation are usually standardized and very repetitive, according to Lee. Starting next year, ST Engineering plans to automate the drilling of floor grilles for the A321-200P2F conversion programs it owns through EFW, a joint venture with Airbus.