Research Area

Magnetic and Optical Systems

Twist Tester

The twist tester twist inspector DIO 125 SD is an optical measuring device for quality control of cylindrical sealing mating surfaces. Both macro-twist structures according to the Mercedes Benz standard MBN 31007-7 and textures of the surface microstructure with increase in axial direction (micro-twist) can be recorded and evaluated in a few minutes. The basis for this is a new patented measuring method which reproduces the surface of the test specimen with high resolution in both the axial and circumferential directions. This method combines the advantages of macro twist testing and the conventional yarn running method. The measuring device can be used close to production and is suitable for a 100% inspection of sealing mating surfaces.


Application examples:

  • Macro twist analysis according to MBN 31007-7
  • Microtwist measurement for the determination of conveying parameters
  • Roughness measurement on rolled and precision turned shafts
  • microsection analysis and 2-dim. roughness test on ground cylinder surfaces

device configuration

  • Measuring principle        

          - Conical diffraction analysis of scattered light measurements with grazing illumination in circumferential direction
          - 2-dim. area deflection measurement in circumferential direction

  • Standing workstation 2m x 1.2m x 1m (H x W x D)
  • Measuring range (macro twist)    
  • Period length DP 20µm - 400µm, twist depth Dt 50nm -1500nm
  • Resolution 50 nm
  • Working distance 14 mm
  • Beam sources Laser diodes (l=635nm, 10mW; l=650nm, 5mW)
  • Measuring spot size >2mm axis length (scattered light), approx. 5µm deflection
  • Surface inclination ±5°
  • Measuring time approx. 8 min (micro- and macro-twist analysis)


Other Measuring Instruments


Innovent e.V.


Drallinspektor DIO 125 SD

Dr. Albrecht Hertzsch

Team Leader
Technical Optics

Phone: +49 3641 282589