Application Note | High-Speed Inspection
High-Speed Scanning with Non-Contact Profilometry
Step Height, Radius, and Roughness of a Machined Part from a Measurement Taking Less Than 5 Seconds
Research & Experimental Testing
Jocelyn Esparza & Pierre Leroux
Visual Design & Editorial
Andrew Shore
Introduction
Quick and easy set-up surface measurements save time, effort and are essential for quality control, research and development and production facilities. The NANOVEA Non-Contact Profilometer is capable of performing both 3D & 2D surface scans to measure nano to macro scale features on any surface, providing broad range usability.
Why Profilometry Matters for Fast 2D Measurement
Unlike other techniques such as touch probes or interferometry, the Non Contact Profilometer, using axial chromatism, can measure nearly any surface, sample sizes can vary widely due to open staging and there is no sample preparation needed. Nano through macro range is obtained during surface measurement with zero influence from sample reflectivity or absorption, has advanced ability to measure high surface angles and there is no software manipulation of results. Easily measure any material: transparent, opaque, specular, diffusive, polished, rough etc. The technique of the Non Contact Profilometer provides an ideal, broad and user friendly capability to maximize surface studies with the benefits of combined 2D & 3D capability.
ℹ️ Learn more about non-contact profilometry lab services for machined parts.
Measurement Objectives
In this application the NANOVEA HS2000 Profilometer is used to measure roughness, step heights and other dimensions on a machined part. All of these calculations are made from a single 2D measurement that takes less than 5 seconds to obtain. This speed and ease of use combined with highly accurate data makes the NANOVEA Profilometer a valuable tool for a wide range of applications.
NANOVEA ST500 Large Area
Optical 3D Profilometer
Sample
Results and Discussion
The roughness, step height and contour were used to calculate various dimensions from a single line profile measurement.
| Dimension | Value |
|---|---|
| Step height, left groove | 3.925 mm |
| Step height, right groove | 4.097 mm |
| Average step height | 4.011 mm |
| Groove radius, left / right | 1.767 mm / 1.746 mm |
| Average radius | 1.757 mm |
| Groove width, left / right | 3.556 mm / 3.575 mm |
| Land between grooves | 2.844 mm |
Table 1: Dimensions of the machined grooves, as measured in Fig. 3.
| ISO 25178 parameter | Value |
|---|---|
| Sa | 0.2538 µm |
| Sq | 0.3227 µm |
| Ssk | 0.1986 |
| Sku | 3.439 |
| Sz | 2.999 µm |
| Sp | 1.615 µm |
| Sv | 1.384 µm |
| Spar | 4.000 mm² |
| Sdar | 4.007 mm² |
Table 2: Height parameters of the extracted area shown in Fig. 4.
| ISO 4287 parameter | Mean | Std dev | Min | Max |
|---|---|---|---|---|
| Primary profile | ||||
| Pa (µm) | 0.2398 | 0.02643 | 0.1809 | 0.3381 |
| Pz (µm) | 1.753 | 0.2750 | 1.208 | 2.571 |
| Pq (µm) | 0.3032 | 0.0330 | 0.2304 | 0.4180 |
| Roughness profile (Gaussian filter, 0.8 mm) | ||||
| Ra (µm) | 0.2245 | 0.02703 | 0.1555 | 0.3198 |
| Rz (µm) | 1.437 | 0.2556 | 0.9034 | 2.557 |
| Rq (µm) | 0.2839 | 0.0334 | 0.2023 | 0.4041 |
Table 3: Amplitude parameters of the primary and roughness profiles, from the profiles shown in Fig. 6.
Conclusion
In this application, we have shown how the NANOVEA Non-Contact Profilometer can precisely measure roughness, various heights, widths, and other dimensions from a single 3D measurement that takes seconds to obtain. The data shows an average step height of 4.011 mm, an average radius of 1.757 mm, an average surface roughness of 0.254 µm as well as other dimensions and height parameters. These measurements are relevant to a huge range of applications, from precision machined parts to biomedical products to electronics. The data shown here represents only a portion of the calculations available in the analysis software.
Frequently Asked Questions About High-Speed Non-Contact Profilometry
Why does measurement speed matter in surface inspection?
Quick, easy-to-set-up surface measurements save time and effort and are essential for quality control, research and development and production facilities.
What can be measured from one fast profilometer scan?
Roughness, step heights, radii, widths and other dimensions. On this machined part, a measurement taking less than 5 seconds gave an average step height of 4.011 mm, an average groove radius of 1.757 mm and an average surface roughness of 0.254 µm.
Why use a chromatic confocal profilometer instead of a touch probe or interferometer?
Using axial chromatism, it measures nearly any surface with open staging for a wide range of sample sizes and no sample preparation, from nano to macro range, with zero influence from reflectivity or absorption, high surface angle capability and no software manipulation of results.
How are step height and radius measured on a groove?
A profile is extracted across the grooves and dimensional analysis fits the radius of each groove bottom and measures the step heights, groove widths and land between grooves.
Which roughness parameters were reported?
ISO 25178 area parameters (Sa 0.2538 µm, Sq 0.3227 µm, Sz 2.999 µm) on an extracted area, and ISO 4287 profile parameters with their mean, standard deviation, minimum and maximum, such as Ra 0.2245 µm.
Which NANOVEA instrument performed the high-speed scan?
The NANOVEA HS2000 profilometer, designed for high-speed inspection and large-area flatness. Its current large-area counterpart is the NANOVEA ST500.
