Talyrond 73 – Roundness Measuring Machine

The Talyrond 73 roundness measuring machine is used at METAS for high-precision roundness measurements of spheres, magnification standards (Flick), hemispheres and roundness standards. The machine is equipped with a rotating probe and a precision spindle supported by oil hydrostatic bearings and has been continuously modernised. Today, high-resolution probe electronics and digital data processing enable measurements in the nanometre range.

For measurements requiring the highest accuracy, METAS uses a multistep error separation technique in which the object under test is measured at several defined angular positions. By mathematically separating spindle errors from form deviations of the object under test, roundness measurements can be performed largely independently of the remaining run-out errors of the measuring spindle. This technique makes the measurement system effectively self-calibrating with respect to run-out and enables metrological traceability without the use of a roundness standard.

The Talyrond 73 covers roundness deviations from 0.1 µm to 300 µm for workpieces up to 150 mm in length and 390 mm in outside diameter. Depending on the measurement task, measurement uncertainties of down to 7 nm can be achieved, enabling roundness measurements at the highest international level.