Images

An AGV delivering samples to a roboTest testing system. © ZwickRoell

Robotic inspection systems, for example those based on industrial robots, have been used successfully for years. Thanks to their high load capacity, they are able to move even heavy test specimens safely. Thanks to extensive sample magazines, they are suitable for long test series - hundreds or even thousands of test specimens can be processed independently, magazine by magazine. For example, the various roboTest testing systems from ZwickRoell, in conjunction with the respective testing machine, are not only suitable for standard tensile tests on metal or plastic specimens under normal conditions. Flexure tests, temperature-controlled tensile tests, notch impact tests and puncture tests as well as ball indentation hardness measurements can also be automated.

roboTest N during the automated execution of a notched bar impact test with a HIT pendulum impact tester. © ZwickRoell

All that remains is to transfer the samples to the robot testing laboratory. There, the test specimens are recognized by their code, assigned to the correct test and testing machine and sorted onto the corresponding tray. Further transportation is carried out by AGVs, which take the trays to the respective testing machine. They use the integrated laser navigation system to create a map of their surroundings and independently find the route to their destination. Thanks to their autonomous navigation, they are superior to conventional solutions, which have to follow a wire embedded in the road or a contrast line stuck on, for example. The solution used by ZwickRoell, on the other hand, is able to avoid obstacles and thus secure the transport chain.

Once at the designated testing machine, the AGV loads the specimens into the testing system's magazine. One of ZwickRoell's robotic testing systems, such as roboTest L, takes over the processing of the specimens: The loading of the testing machine, the testing process and the transfer of data to the customer's software systems as well as the removal of the destroyed specimens are fully automated. Here too, the identification numbers of the test specimens are read by cameras in order to correctly link the test data with the respective specimen. An AGV picks up the emptied trays and transports them back to sample preparation, where they are loaded again.

Automate small series testing

What works excellently on a large scale and saves a lot of time was previously completely uneconomical on a small scale. Setting up stationary robot inspection systems is complex and requires time and specialists. Depending on the system, comprehensive safety measures are also necessary. Powerful industrial robots are not designed to work directly with humans. They lack the ability to react to their environment. Protective fences are therefore usually used. Small series testing has therefore remained firmly in human hands until now. In the past, it was much quicker to entrust an employee with 20 tensile tests or 50 impact tests than to set up one of the large robot testing systems.

With roboTest N, ZwickRoell offers the option of automating low-volume series tests with lower specimen weights. Based on a Smart Robot, the system is fully integrated into the ZwickRoell autoEditon 3 and testXpert III. This means that neither a robot operator terminal nor special knowledge of programming and operating robots is required.

Automation of hardness tests with roboTest N. © ZwickRoell

The Smart Robot's working speed and force correspond to human proportions. Sensors detect external influences and stop the system if something gets in its way. This means that roboTest N can work alongside humans without any further protective measures.

The lightweight robot is mounted on a mobile robot table. This allows it to be easily moved to the respective testing machine and connected to the system. This enables the uncomplicated processing of changing small batches and the automated execution of various tests. Tensile and compression tests can be carried out just as autonomously as three-point bending tests, notched bar impact tests or hardness tests. The movable base also offers space for individually manufactured magazines. Started shortly before closing time, the robot extends the working day by one magazine content. The automation of monotonous standard tests frees up qualified employees for more complex testing applications. Thanks to the uniform motion sequences, user errors or inaccuracies can be eliminated and the reliability of the test results increased.

Robotic testing systems offer several advantages in series testing, from time savings to improved reliability of test results. With its various roboTest testing systems, ZwickRoell covers the entire range of test automation - from short-term support for constantly changing small series tests in the laboratory to fully automated testing laboratories without human intervention.

David Kalke, specialized journalist