In order to survive in the highly competitive market environment of contract manufacturing, machine tools such as lathes, milling machines, wire erosion machines and grinding machines have to run around the clock. However, this requires skilled personnel - and this is currently difficult to find. Fewer and fewer companies are able to maintain a three-shift operation on a permanent basis. Another problem: CNC machines are often loaded manually. Time and again, workpieces are left lying around for too long after processing until they arrive at the next machine and can be processed further. While large companies respond to this with complex automation concepts, there is a great need for flexible concepts, especially among SMEs. Although there are more and more robots on the processing machines that load and unload the workpieces, they have to be enclosed and work stationary. Even the mobile shuttles available on the market have so far hardly been suitable for use in production, as they are basically designed for the logistics sector. Ger4tech, together with Fanuc and Incubed IT, has set out to close this gap in the market: The Mobile Cobot G4T4 is the first autonomous mobile robot (AMR) with a 6-axis robot designed specifically for manufacturing.

Fusion of Cobot and AMR

The G4T4 is a fusion of a collaborative robot and a mobile robot. The mobile cobot can move autonomously between different work areas, easily switch from one job to the next and transport material at the same time. "Our mobile cobots autonomously find their way to the next job, even in environments that are quite chaotic," says Hubert Gerstmayr, Managing Director of Ger4tech. The G4T4 cobots therefore open up new possibilities for contract manufacturers to automate their handling and logistics processes.

Basically, the G4T4 is an AMR on which a Fanuc CRX-10iA/L cobot is mounted - a cooperative lightweight robot that is used without additional safety devices. "With its low weight of just 40 kg, it is ideally suited for use on mobile platforms," explains Gerstmayr. This enables the robot to take on and combine handling applications for machine tools as well as the transportation of raw materials and finished parts, tools, pick-and-place applications and warehouse picking tasks. For example, the G4T4 can pick up Euroboxes with HSK holders for a rotary spindle of a wire EDM machine from a central storage location. After a parts request, it travels to a machine tool and performs an offset calibration. The cobot arm then removes an HSK holder with a finished workpiece from the machine and places it in a free space in the Eurobox. It then loads the machine with an HSK holder with a raw part from the Eurobox and then transports the finished workpieces to a central storage location or a downstream machine tool.

A major challenge when using robots on mobile platforms is not only the exact positioning to the machine or workstation, but also the exact positioning to the workpiece or tool holder of the processing machines. Software uses a camera to calculate the exact position of the robot in relation to the machine. The G4T4 thus achieves a high degree of flexibility with high positioning and repeat accuracy.

Wireless charging as a key technology

For Ger4tech as a system integrator of customized automation solutions, safe 24/7 operation is the top priority. The power supply for the robot's lithium-ion battery therefore plays a central role. The built-in etaLink inductive battery charging system from Wiferion does not require any wearing parts and therefore ensures maintenance-free continuous operation of the mobile cobot. "Wiferion has a contactless charging system that has been tried and tested in industrial environments for a long time," says Gerstmayr. As Ger4tech also obtains its lithium-ion batteries from Wiferion, the automation specialist receives a complete energy system that is perfectly coordinated. "With Wiferion, we have many options for designing the system in such a way that the customer has an advantage and is flexible. It was therefore clear to us from the outset that we would only integrate this technology."

Thanks to the contactless design, the charging system can be set up anywhere where the cobot is expected to work for longer periods of time. Power is supplied during the process via "in-process charging", for example directly at a machine tool. Thanks to the greater positioning tolerance, the mobile robot can be easily positioned at the charging point. The entire automation process is also easier to plan and more transparent. It is possible to define exactly when the robot is to be loaded and how long a loading process takes. This means that processing steps can be planned precisely and are not interrupted by loading breaks. For Hubert Gerstmayr, the system has another advantage: "With the etaLink system, several mobile robots can share a charging station. It is possible to read out all relevant data from the batteries and the mobile charging electronics via a CAN interface." As etaLink is an encapsulated system without open charging contacts, occupational safety is increased.

With the G4T4, Ger4tech offers the first mobile cobot for manufacturing. The mobile handling solution automates the transportation of materials - such as raw materials and finished parts - to and from machine tools. The charging system does not require any plug or sliding contacts and therefore enables intermediate charging of the batteries. This saves time and increases productivity. Even in continuous use, the G4T4 can operate for many years without maintenance of the power supply.