Hardness testing of metallic materials often places high demands on the patience of the user due to the standardized test methods called for. In particular, the mandatory indentation times are to be strictly observed while, additionally, the time needed for equipment setup plays a significant role. The result – a long test time. Thus, automating such tests is a logical consequence. And Zwick in Ulm has come up with an outstanding solution: an automatic system for fully standards-compliant testing that is both fast and reliable.
The basic for the system comprises two hardness testing devices: a machine for testing according to Rockwell and an additional tester for Vickers hardness tests. Both machines are fully automated and designed for the testing of strip specimens up to 8 mm in thickness. The specimens are fed using a 6-arm industrial robot: the magazine has a capacity of 100 Rockwell and 160 Vickers specimens. Further workstations are the barcode reader, which recognizes the relevant test to be performed by the label on each specimen, a thickness measuring station with two sensors for determining the specimen thickness. The system is fully controlled using the Zwick testing software testXpert® autoEdition.
Of particular mention is the fact that specimens can be tested in parallel as both hardness testing machines can be operated simultaneously. If more than one test should be required per specimen, the shifting station will move the specimen the necessary distance. Thanks to an intelligent test program, the system recognizes which of the hardness testers is free and feeds the next specimen accordingly. Two buffer magazines are provided to harmonize operations, ensuring that the next specimen is ready on time and adjusting discrepancies in test times occurring between the Vickers and Rockwell testers. The result – fast specimen throughput.
Furthermore, the tested specimens are sorted into containers in accordance with specific criteria (e.g. measured hardness value within/out of tolerance). The system can conveniently be connected to a higher-level host computer for automatic upload of the relevant test results.