This is to ensure that the products remain functional over a longer period of time, even under demanding conditions.

There is a defined verification and validation strategy for each new product family, which begins with the selection of suppliers and components. Assemblies and end products are subjected to long-term tests that depict various load scenarios. In addition to the information provided by the suppliers, the company carries out additional tests, including

• Temperature cycling tests in HALT chambers with measurement of functional capability with widely varying temperature profiles,
• Vibration and shock tests on electrodynamic shakers,
• Protection type tests according to IP protection classes,
• EMC measurements to confirm electromagnetic compatibility.

At the heart of an encoder, and therefore the focus of many tests and qualifications, are the ball bearings and the associated bearing package. The dimensioning and qualification of these components are decisive for the quality and durability of an encoder. Therefore, one focus is on the qualification of the bearing packages. For verification, Wachendorff has equipped a bearing assembly test station with five stations so that up to five test lines can be tested simultaneously. The test station is very well shielded from the rest of the test laboratory due to the noise development and long test duration. A test usually takes between twelve and 14 weeks.

Cutaway model of the WDGA58B Industrial Ethernet absolute rotary encoder from Wachendorff Automation. The shaft and bearing assembly, which are subject to external forces, are particularly stressed and are therefore intensively tested before being released for series production. © Wachendorf

The 'WDGA58F' absolute rotary encoder with Profinet and EtherCAT interface was tested as an example. The model is designed for nominal speeds of up to 8000 min-¹ and was subjected to axial loads of 50 N and radial loads of 60 N in the test. For this purpose, the existing bearing pack test station was expanded and automated so that the calculated service life of the bearing packs, which are mounted (glued) in the flange of our encoders, can be verified. The test station is completely enclosed so that the noise generated during the test process is insulated and employees are not endangered in the event of a defect. Loads are generated via pneumatic cylinders. Each pneumatic cylinder is controlled and adjusted via a separate pressure regulator. Temperature, speed and vibration are continuously recorded in parallel. Depending on the selected speed and the calculated service life at 100% assumed bearing load, the verification of a bearing package takes approx. 12 to 15 weeks. Despite the compact design, the test specimen passed the long-term tests after 13 weeks without failure.