3D Surface Metrology Applications
Sensofar – Non-contact 3D Surface Metrology
3D surface metrology describes the measurement and characterization of micro- and nano-scale features on natural or manufactured surfaces. This can be achieved very efficiently by capturing the 3D spatial coordinates of points on a surface using a non-destructive optical technique.
Optical measurement systems have some crucial advantages over tactile (stylus-based) approaches. First and foremost, the measurement is non-contact, so no damage can occur to the object being measured. Optical techniques can measure through transparent media. They are fast and flexible, and they also yield 3D (areal) results. Last but not least, absolute measurement performance is dependent upon wavelength and numerical aperture, without the limitations imposed by the physical size of a stylus tip.
The most common optical techniques available are confocal, interferometry and focus variation. Each of these has their own particular set of strengths and weaknesses. Therefore, in order to provide the user with maximum versatility for 3D surface measurements across varying scales and structure types, Sensofar Metrology’s high-end optical profiler systems uniquely incorporate the three most common optical techniques in a single sensor head.
While still fragmented, the rapid growth in this applications space is in part due to the capture of market share from the often inherently slow and ‘2D only’ tactile approaches. However, an increasingly dominant element is the ‘enabler’ aspect of an optical approach – that is, the surface measurement was previously simply not possible.
What does 3D Surface Metrology measure?
Very generally, both natural and manufactured surfaces comprise a primary shape or form (topography), with varying degrees of structure, waviness and roughness (2D/3D). All of these surface features will contain both intentional and unintentional (controlled/uncontrolled) contributions.
The relative significance of these contributions is determined by the application (noting that uncontrolled contributions are not necessarily undesirable). The goal of a measurement is to evaluate – qualify and quantify – the differing contributions, either in support of a fundamental scientific research finding, or with regard to a target industrial application.
Depending on the field or application, the structure, waviness and roughness contributions might be categorized as finish, haptic, texture, defects, marks, micro-wear and much more. Alternatively, the user may be looking to determine critical dimensions, step-height, peak-to-valley, volume or slope, or even map coating thickness and other surface characteristics.
If the goal is to determine areal (3D) surface texture, the results can be also be rigorously tied to the appropriate parameters as defined by the increasingly prevalent ISO 25178 standard. In industrial (surface) manufacturing, the adoption of best practices tied to widely accepted standards can make manufacturing more efficient, reproducible and traceable.
Typical applications sectors include general scientific and materials research, optoelectronics, data storage, automotive, medical technology, energy, and optics & optoelectronics. Specific applications include additive manufacturing, automotive and consumer electronics, ballistics, CMP pad monitoring, micropaleontology, nano-technology, micromanufacturing, optics, surface inspection, surface functionality and passivation.
The sheer breadth of 3D surface and 2D profile metrology tasks across so many scientific and industrial applications points directly to the outright practicality of Sensofar Metrology’s ‘3-in-1’ approach.