DIAROND - Overview

Non-Contact In-line Measurement of Diameter and Roundnesss.

For rod bar and tubes. For finishing, peeling, grinding, straightening, quality control (NDT).

DIAROND is a novel, non-contact measuring system from Zumbach.

It allows to measure, simultaneously the diameter and the roundness of cold processed steel products in the production or testing line.

The problem

So far, a measurement of roundness and shape deviation can be done only on samples by means of tactile laboratory-measuring machines (e.g. MAHR, MITUTOYO, TAYLOR HOBSON etc) but not continuously in the production line. Conventional optical in-line gauges, allow for accurate measurement of diameter and limited capability for ovality, but no possibility for roundness or shape.

The solution

A high-precision, 3-axes laser head ODAC® TRIO measures at high frequency and fully synchronized, 3 x diameters at 60° offset to each other, and 6 x corresponding tangent points on the periphery of the product. All measured values are stored in the USYS IPC processor. For completing the whole profile there must be a self rotation of the product of at least 60° or a rotation of the measuring head by means of a rotary device. An angle information is not required. Without rotation, there can also be statistical evaluation of a number of parts, where results can be enhanced by any random manual oscillation or orientation.

ZUMBACH's advanced STEELMASTER software with proprietary EPM algorithms analyses the stored data and calculates all relevant parameters for the profile:

  • Diameter: max., min., mean, max.-min.
  • Roundness RONt in accordance with ISO/TS 12181-1 (formerly DIN 4291/92): The roundness (peak-to-valley roundness deviation) is calculated exactly for any shape and deviation. Also, the maximum inscribed reference circle MICI and the minimum circumscribed reference circle MCCI are calculated and displayed.
  • Deviation of shape and polygonality: Shape deviations in general, especially polygonal shapes (3, 4, 5 & 6-lobed), can now be detected in-line. With this, problems in the process (rolling, peeling, centre-less grinding, etc) can be detected and corrected at an early stage.


The required parameters can be freely selected and configured for numerical and graphical display and they are also available at the computer interface.