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3D profiling of surfaces, sometimes known as surface profilometry, is the accurate 3-dimensional topography of any given surface. With the rapid increase in technology, surface profiling uses lasers to determine a surfaces serviceability by compiling data on surface quality, surface area roughness, surface finish, surface shape, cracks and fractures that may be hard to see with the human eye.
It can be used on a variety of materials, from small components to large scale geographical areas. Therefore, there is a wide range of 3D surface profilers. One profilometer uses a laser and an accelerometer to measure the profile of a road at highway speeds. This allows the international roughness index of the road, as well as any crack or potholes, to be observed at high speeds without having to close down a road. This particular 3D profilometer can be used for construction control surveys or network surveys.
3D Laser Profiling of Surfaces
In a 2012 paper by John Laurent et al, it was proposed that 3D surface profiling over a large area could “maximize road maintenance funds and optimize the condition of road networks” as long as pavement management systems have accurate and reliable data. The paper published the results of a decade long project with Pavemetrics inc, the National Optics Institute of Canada and the Ministere des Transports du Quebec. The three bodies developed a Laser Crack Management System which could evaluate and detect cracks to a 95% accuracy over 9000 km.
However, due to the precision of a laser, it is more likely to be found in precision microscale optical profilers. Most laser 3D profilers are able to detect the smallest detail in the surface of a material which makes them perfect for quality assurance of delicate machined components. These types of laser profilers look similar to microscopes and scan the image from the bottom to the top of the material, creating a 3D image over multiple slices.
They can also characterize micro, and even nano-scale, surface features. The laser profilers use approximately two million data points to create the 3D images of the test material in mere seconds. These types of profilers are a type of non-destructive testing because they are non-contact. Currently, most companies offer the flexibility of multiple settings per one machine. Adaptable features include speed, precision, vertical range, and automation.
3D Laser Profilers: An Extremely Useful Tool
However, research is still ongoing to create more efficient, more precise 3D laser profilers. Last year, a paper in the Applied Optics journal discussed the possibility of using an erbium-doped fiber femtosecond laser as a source of light for coherence scanning interferometer. This was used for a wide field-of-view surface profile of rough silicon carbide. According to their findings, the infrared pulse laser was able to provide a temporal coherence of around 30 μm which was deemed appropriate for rough surfaces, while also offering a high degree of spatial coherence in order to achieve a wide field of view.
No matter the application, 3D laser profiling of surfaces is an extremely useful tool in many industries and is rapidly increasing popularity, especially in manufacturing. It can be used for maintenance, data collection, and failure investigation for components. A 3D profile can provide accurate information on the surface profile of most given materials.
Sources and Further Reading
- Laurent, J. (2012). Using 3D Laser Profiling Sensors for the Automated Measurement of Road Surface Conditions. In Effect of Polymer Dispersion on the Rheology and Morphology of Polymer Modified Bituminous Blend (pp. 157-167). 2211-0844.
- Yang Lu, J. P.-W. (2018). 3D profiling of rough silicon carbide surfaces by coherence scanning interferometry using a femtosecond laser. Applied Optics, Vol 57, 2584-2589.
- Zeta. (2018). Laser Induced Surface Topography. Retrieved from Zeta-Inst.com: https://www.zeta-inst.com/applications/laser-induced-surface-topography
- Zygo. (2019). 3D Optical Surface Profilers. Retrieved from zygo.com: https://www.zygo.com/?/met/profilers/