| The most common mechanical tests on plastics include tensile, flexure and notched impact according to Charpy and Izod. Zwick has now produced a robotic testing system in which all three tests can be performed at the same time.
The machine operator simply loads a magazine with the three different types of specimens and the robotic “Polar System” takes over the handling of each specimen for all further steps of the testing process. The Polar System is based on an industrial robot with a pneumatically operated gripper.
After the specimen is taken from the magazine, a cross section measurement is made. Specimens requiring a notched impact test are taken directly into the pendulum impact tester, whilst tensile specimens are clamped in the pneumatic grips of the tensile testing machine. The tensile tester is usually equipped with a Zwick multiXtens extensometer for measuring strain. The multiXtens is a unique device having very high-resolution, measurement accuracy and an extremely large measurement range. Special disposal grippers automatically remove the specimen from the grips after the test and dispose of it.
For flexure testing the specimen is placed on the supports of the flex tester and the crosshead automatically brings the upper flexure fin into the starting position based on the measured specimen height. The results of the cross-section measurement can be used to automatically set the span using motorized lower anvils. The specimen is disposed of after the flexure test by automatically tilting the flexure rig block.
The intelligent testing software testXpert® controls and monitors the test sequence and automatically collects all measurement data, calculates and documents the test results. At the end of the test the results can be printed in a test report and exported to an external data base or to Microsoft Office. In addition, it is possible to export the results, together with their control parameters, as an ASCII file.
The advantage of this solution is the combination of three test functions in a single system. A robot services three testing machines and relieves the operator from routine tasks. The system is a productive and cost effective way to speed up production testing for quality control laboratories and because each specimen is handled and tested without human intervention the test results are much more consistent and repeatable.
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