The device is equipped with an internal light source (white LED). The light source brightness may be set by command to any desired value between 0% and 100% of the max brightness. Alternatively, the sensor may be configured to an “auto-adaptive” mode in which the source brightness is automatically adjusted to the sample reflectivity.
The optical pen works on principle of Chromatic Confocal Imaging (CCI). The backscattered light from the white light LED is collected by the same optical system, which images the light spot on a pinhole. The pinhole is placed in front of a photodetector, it filters the light rays that can reach the photodetector. A spectrometer signal corresponds to the spectral repartition of the collected light. It presents a spectral peak. When the object moves away from the light source inside the measuring range, the spectral peak on the spectrometer shifts.
Chromatic confocal sensors can measure samples made of practically any type of material (Glass,
Ceramics, Plastics, Semiconductors, Metals, Fabrics, Papers, Leathers, etc.) making it particularly suitable for tribological tests. They can measure polished surfaces (mirrors, lenses, wafers) as well as rough ones.
An important characteristics is the fact that it is a “point” sensor; in other words, at any given instant the sensor measures a single point located on its optical axis. In order to obtain a profile or measure an entire surface, it is necessary to scan the sample along one or two axes with the aid of some external scanning device such as the XY table provided with the Ducom Non-Contact 3D Profilometer. Generally the scanning device is motorized; in some cases it comprises an encoder for determining the precise position of the sample at any given instant.
The Ducom Profilometer includes software embedded in the WinDucom software to enable estimation of wear depth, volume etc.
- Compact tabletop design.
- Easily interchangeable optical pens.
- Computer controlled operation with software license included.
- Micro/nano topography,
- Roughness Measurement,
- Pretest and post-test measurements of samples.
Parameter Specifications Stage travel (X,Y) 100 mm X 100 mm Depth range 1 mm Depth resolution Resolution: 10 µm
Wear forms a very important aspect in tribological tests. In most tribological tests, the material under test is usually a pin or ball, and a counter specimen in the shape of a disk or plate of a significantly harder material is used. In such cases the best practice was and remains measuring the weight loss of the pin or ball at intervals during the testing.
However, in the process of developing newer materials, the practically achievable hardness limits of disks is fast approaching. In other cases tribological properties between specific combinations of materials is required. High temperatures also reduce hardness of most materials. For all such research the counter-specimen – i.e. disk or plate, is also a test sample and would be suffering significant wear.
Weight-loss method of measuring wear of the disk may not be feasible since the weight of the disk or plate is usually quite high and weighing balances with the resolution required for tribological tests and having the range to weight a disk are not practical.
Profilometers have been successfully used to measure wear formed on the track radius after test run is completed. The Ducom Non-Contact 3D Profilometer has a compound stage with X-Y movement on which the test specimen is placed to move below a white light optical pen, mounted vertically above the specimen. This optical pen is connected to an electronic unit through fiber optics cable, controller controls signal acquisition, performs signal processing, computes the distance and thickness data and transmits the data on the digital outputs (RS232 or USB).