The greatest potential lies in small products, high quantities and short cycle times," says Pascal Lettmann, Managing Director and founder of AI-pro. In an industrial environment, he often observes workers inserting and removing individual parts from machines in short cycle times. This is monotonous work that is relatively easy to automate - unlike the downstream manual visual inspection. "From a technological point of view, it is difficult to have rule-based camera systems take over the operator's inspection when removing parts, and this is often associated with high costs," explains Lettmann. This is because the system quickly reaches its limits, for example in fluctuating lighting conditions or geometric deviations. In addition, such camera systems have to be operated by specially trained employees, which shifts the effort and responsibility for detecting faulty products onto the user.

This is precisely where AI-pro comes in, offering visual inspection including automation from a single source. "We limit ourselves to straightforward processes such as the insertion and removal of small components in machines with short cycle times and supplement these with reliable inspection technology including programming," explains the company founder. The special feature: the start-up from Stemwede in North Rhine-Westphalia buys the system to be automated and adds the necessary handling, control and testing technology. "Our customers don't have to deal with setting up the test programs or communication problems between the robot and the machine," says Lettmann, listing the advantages.

A current project shows what this looks like in practice: a customer wanted to replace manually operated hydraulic presses for upsetting ball sleeves and automate the process as part of this. The machines previously used had no sensors to detect faulty parts, the sleeves kept getting stuck in the tool after pressing and the maintenance costs for the hydraulics were also too high.

Stability and control

For the actual work process, AI-pro was looking for a stable press with a servo drive that enables a short cycle time, measures the press-in depth X and thus monitors the process. As soon as the X value is exceeded or not reached, the system should detect the faulty part and eject it. After extensive research, Lettmann opted for a C-frame press from Tox Pressotechnik. Lettmann had already had good experiences with the Weingarten-based family business in the past. "The comprehensive advice I received in advance and the standard modular system on offer reinforced my decision to buy the press from Tox," adds Lettmann.

The drive is provided by the Tox-ElectricDrive type EX-K. A planetary roller screw precisely converts the rotational movement into a linear feed that presses the tool into the component with up to 200 kilonewtons. It is installed in a solid and torsion-resistant steel construction that provides sufficient stability to withstand the force applied during the pressing process. As soon as a ball sleeve is seated in the tool, the drive lowers the ram. The distance required for the force-displacement protocol is recorded by a resolver directly on the servo drive, while an integrated force gauge contributes the pressing force applied. The Tox software thus monitors the control value X and can immediately detect any faulty parts.

Two linear-guided grippers alternately insert a component into the tool of the servo press and remove it after pressing. © Tox Pressotechnology

AI-pro added two linear-guided grippers to the Tox servo press, which alternately insert a component into the tool, fix it in place after pressing and before the punch moves up again and then remove it. They then hold the component in front of the lightweight robot again, which picks it up from the inside and passes it on. Thanks to the alternating operation of the two feed units, AI-pro significantly reduces non-productive times. "The robot takes the finished component alternately from one unit or the other," explains Lettmann. After further processing, seven cameras and a micrometer check the finished ball sleeve optically and geometrically.

Neural networks

AI-pro uses neural networks for this: "They enable our inspection system to reliably detect grooves, scores and chatter marks - even on reflective surfaces. It is also possible to check certain features or alignment," explains Lettmann. This works via classifications, finding similarities at pixel level and is only possible for AI-based visual inspection thanks to the availability of the corresponding computing power, which also makes sense from a cost perspective. AI-pro selects all components individually: from the camera and lighting to the feeder and the algorithm for the visual inspection. "In the end, the customer basically just has to press a button," says Pascal Lettmann.

No problems at the interface

Communication between the robot and the press takes place via the higher-level control system using Profinet. The pressing process itself is initially configured via the Tox HMI once or when changing parts, and maintenance is also carried out directly via the Tox panel. The AI-pro automation then provides the start and stop signal and also reacts to fluctuations in the process. "Our system simply picks up the data from the Tox software and sends it to the PLC," explains Lettmann. In this way, the robot also queries the last measured values for quality control and knows whether it needs to place the finished component in the in-order or out-of-order box. In addition, AI-pro can send this process data, for example about good and bad parts, to its AI computer, which then saves this data in an SQL database. "Normally, data exchange from the PLC to higher-level control systems such as ERPs is relatively difficult. However, our computer speaks precisely these languages," explains Lettmann.

The signal exchange between the press, robot and the rest of the automation runs smoothly. One reason for this is the good communication in advance: "Tox Pressotechnik advised us on the options for communication with the press and provided us with the complete documentation for this very early on in the project. We therefore had no interface problems at all," confirms Lettmann.