At first glance, production hall 10 on the Kuka site in Augsburg looks like one of many production environments at German and international mechanical engineering companies: there is a slight smell of oil in the air, machine tools from various manufacturers concentrate on processing metal parts - and busy employees keep the store running. Like Rainer Eder-Spendier, Administrator for Automation and Robotics in Hall 10. "This hall is a passion for me," says the 51-year-old. "What sets us apart is the high and sensible level of automation in production. This is where intelligent automation and digitalization come to life."

What you don't see at first glance: All the machines in the hall are connected to a cloud and have various Industry 4.0 functions. With a tablet in his hand, Rainer Eder-Spendier stands in front of the safety fence of a machine tool from Burkhardt + Weber and explains: "For example, we have a digital overview of the entire hall - similar to the map app on a smartphone. I can use it to get an overview of all the machines and call up their data." A quick tap of his finger later, he checks the status of two machining centers from Heller, which are regularly loaded and unloaded by a Kuka robot. Similar to a smart watch or a fitness bracelet, robots and machines collect a colorful bouquet of data and send it to the cloud. The data is then displayed in various visualizations on the tablet's user interface. "But that's not all," says the Munich native, who has been working at Kuka for a good quarter of a century. "In the event of error messages, for example, we can access a kind of wiki in which our service technicians have compiled suitable solutions over the years - there are almost half a million entries there. The built-in technology also allows us to track every step of the process retrospectively - it works in a similar way to a black box in an airplane. The software can also alert us to irregularities in the production process - similar to an ECG."

Communication as the basis for smart manufacturing

Hall 10 contains a total of seven cells equipped with eleven robots. The robots from different series are all from Kuka. The machines they work on are standard machine tools from various manufacturers. Among other things, the robots process base frames, carousels, arms and swing arms - the components are assembled right next door in the robot assembly area. "Here in the hall, the robots work on various components that we need for the production of our robots," summarizes Rainer Eder-Spendier and emphasizes: "It was important to us not only to test the new technical possibilities in the blue, but also to actually use them sensibly. It is also important that the machines have interfaces for the so-called handshake."

The handshake refers to the communication between the robot and the machine tool. This is necessary to coordinate the components of the system with each other. In the cell, the robot can act as either master or slave. As a master, it specifies the processes and signals to the machine, for example, that a workpiece has been inserted and the door can be closed. If it is used as a slave, it reacts to the specifications of an external control system.

Shorter throughput times, greater efficiency

The automated material transport from the machine tool to the finishing cell, where the machined metal parts are finished, is carried out by the Kuka robot. © Kuka

Machine tools are usually loaded manually by workers. The worker often spends the time the machines need to process the workpiece waiting. Once processing is complete, he removes the workpiece and places it on a pallet before loading a new piece into the machine. This process is not only monotonous, but also inefficient. As can be seen in Hall 10, the process can be optimized through automation. "We use robots to load and unload the machines," explains Rainer Eder-Spendier. "This enables unmanned production for a certain period of time, even during weekend and night shifts." For this purpose, the cells are equipped with feed units, such as rotary tables or feed belts. These are manually loaded with the components to be processed by the workers. The robot can therefore draw on a supply that is sufficient for up to eight hours, depending on the number of prepared workpieces and the work to be carried out by the machine.

Productivity is further increased by the fact that the robots perform secondary tasks. "In some of our cells, the robot turns helicoil threads into the pre-drilled holes while the machine tool is already processing the next workpiece," says Rainer Eder-Spendier, giving an example. Deburring the workpieces is another such task that the robots perform in most cells. Waiting times are used efficiently and the throughput times of the individual parts are shortened because the machines are relieved of processing tasks such as drilling holes and milling within a tolerance range of +/- 0.2 mm. This means that the valuable machining time on the machine tools can be better utilized and more parts can be produced.

Robots work hand in hand with machine tools from various manufacturers

In practice, one of the robot cells in Hall 10 looks like this, for example: Three machine tools from the manufacturer Grob have more than 30 pallets in the system and can therefore react quickly and flexibly to different requirements. The workpiece to be machined is manually clamped into a clamping device by the worker at a set-up station. The component is then fed into the cell together with the pallet and fixture. A KR Fortec type KR 600 R2830 is responsible for linking the individual steps and transporting the material from the machine tool to the finishing cell, where the machined metal parts are finished - i.e. deburred, drilled or fitted with helicoils, for example. It moves to the three machines via a linear unit and then returns the finished part to the respective workstation. The worker releases the clamping device, removes the part and places it on a pallet.

A similar process takes place in another cell with two machining centers from the manufacturer Heller. Here, a KR Fortec robot of type KR 500 L480-3 MT uses a pneumatic gripper to pick up a workpiece placed on a rotary table and feed it into one of the two machines. The robot is installed on a linear unit so that both machines can be loaded alternately. Four feed stations supply sufficient raw material. As soon as processing in the machine is complete, the robot deburrs the part at the set-up station. Finally, it places it on a rotary table.

A Burkhardt + Weber machine tool, which processes swing arms and carousels, is equipped with a double pallet changer. © Kuka

A Burkhardt + Weber machine tool is also loaded and unloaded by a KR Fortec type KR 500. The machine tool, which processes swing arms and carousels, is equipped with a double pallet changer: the clamping fixtures for the swing arms are located on one pallet and the fixtures for the carousels on the other. While the robot loads one pallet with a workpiece, the machine simultaneously processes the workpiece clamped on the other pallet.

The benefits of automation and networking

"Automation makes work considerably easier for the workers, as in most cases there is no need to manually load the machine tools with heavy workpieces," says Rainer Eder-Spendier. Only the material feed is carried out by the worker. However, this is possible with significantly less effort and time, which results in higher productivity of the system. Another advantage is that no in-depth robot-specific expertise is required for the deburring processes. As soon as the cells are working in this mode, they can be operated via the Kuka.CNC software and thus in G-code like a conventional machine tool. The recorded data - including that of components not manufactured by Kuka itself - is made available in the cloud. This ensures a full overview and control of the ongoing production process at all times, greater transparency and optimized task planning.