The quality requirements in manufacturing are growing steadily and, with them, the significance of production-geared testing. In the automobile industry, in particular, dynamic testing is gaining in importance. Zwick, the testing machine manufacturer based in Ulm, has included a number of servohydraulic testing machines in its offering which are geared especially for these applications. Tailored to the environmental conditions particular to manufacturing and supporting the user through superior ease of operation, these machines enable a variety of stress tests to be performed over numerous cycles. The key benefit is quality assurance in the running line. Two examples of Zwick solutions deployed in the industry are presented in the below.
Testing of Rubber-Metal Bearings
When rubber-metal bearings are tested in the line in volume production, a variety of characteristic values need to be determined to be able to assure the desired product properties and monitor the production process accordingly. And it is with this measurement task in mind that Zwick developed a testing system allowing the determination of static and dynamic stiffness as well as the loss angle and loss factor of rubber-metal bearings.
As the testing machines are set up in the production environment, operator safety when inserting and removing the specimens but also during testing is of particular importance. For this reason, the machine is equipped with a safety light curtain. Together with an additional two-hand control used to start testing, the safeguard ensures optimal protection for the user.
The measured values are checked against specified tolerances with the results displayed using colored tolerance indicators. And the testing machine comes with a convenient acoustic signal: a buzzer signals when it is necessary to change specimens or intervene in testing, freeing the operator to perform other activities in the meantime.
Dynamic Torsion Test Bench for Clutch Tests
To determine the fatigue rating and the force at break of clutches, Zwick developed a testing concept based on a servohydraulic torsion testing machine tailored to the particular requirements of the customer.
The basic task was to perform tests on the individual components of an automatic clutch. The test bench was therefore equipped with a multi-functional fixture which the single disks were screwed onto.
As per the customer's wishes, the standard load frame from the servohydraulic product family was not used in this case. Instead a special torsion testing frame was built to accommodate the torsion drive separately at the back of the machine. The measurement and control electronics as well as all the hydraulic control components are compactly installed in the lower part of the base. The testing area is sectioned off and equipped with an electric protection door to ensure operator safety.
Figure 1. Dynamic torsion test bench for clutch tests.