Measuring Disc Thickness Variation (DTV) on brake discs

Measuring Disc Thickness Variation (DTV) on brake discs

The shape of a brake disc can deform during braking as higher energy is absorbed. The full extent of this deformation or disc wear can be measured using Micro-Epsilon’s new optoNCDT 1700 BL Blue Laser Sensors.

With red-hot, glowing objects, a conventional red laser has a high signal interference from the surface of the brake disc, because it emits the same or very near wavelengths of light as the red laser. However, the blue laser works at a wavelength of 405nm, which is far from the red part of the visible spectrum. This means it is easier to filter this type of emitted light from the brake disc, which ensures very stable signals.

During brake disc measurement, the impact on the brake disc is recorded. Using the optoNCDT 1700BL, it is possible to very accurately measure the DTV of the red-hot, 800°C brake disc. In order to protect the sensor from these high disc temperatures, the sensor is positioned behind a heat shield (dismantled in the picture above) while measurements are carried out.

Using the new Blue Laser technology from Micro-Epsilon, it is possible to measure very hot, glowing surfaces to a high degree of accuracy. Due to the optoNCDT 1700BL’s digital interface, measurement data can be transferred quickly and easily to a PC.

The blue laser clearly offers superior technical advantages over conventional red laser versions used in similar applications.

Ambient conditions:
- Approx. 40°C, behind the heat shield
- Magnetic interference fields

Requirements for the measurement system
- Measuring range: 20mm
- Linearity: 16μm
- Resolution 1.5μm
- Measuring frequency: 2.5kHz

For more information on Micro-Epsilon’s range of laser displacement sensors, please call the sales department on 0151 355 6070 or email: info@micro-epsilon.co.uk