Papers by Keyword: Surface Metrology

Abstract: In surface assessment, the reference line extracted using the profile filter are always distorted by freak characteristics of the scratches and peaks of the profile. In order to overcome this problem, the robust spline filter and the Gaussian regression filter were recommended by ISO standards. However, their different algorithms and different filtering characteristics lead to the different mean lines for the assessment of the same surface. A novel robust spline filter based on the M-estimate theory is developed, which possesses the same filtering characteristic as the Gaussian regression filter. It is available for use and transfer of the international standards, as well as the comparison of the surface assessment results.

Abstract: In order to produce optically cooperative surfaces to use triangulation measuring systems, the methods of surface and thin-coating technology are resorted to. Among these number physical methods such as PVD technology, (electro-)chemical treatment as, for example, electrochemical etching and electroless coatings as well as mechanical treatments of the components by means of glass-bead and corundum blasting. The processes mentioned are suitable for producing optically cooperative surfaces since, owing to the corresponding test parameters, a change of the component's surface occurs at the sub-micrometer scale. Currently, no indication in the literature is provided that such processes are employed for manufacturing optically cooperative surfaces vis-à-vis triangulation methods.

Abstract: In this research, Air mist-abrasion machining method for corrective figuring of a rough isotropic quartz surface before polishing process has been proposed. By this method, not only the next polishing time decreases, but also figuring efficiency increases through the possibility of using bigger abrasive grain size. Since the restrictions of laser interferometer measuring devices, capacitor probe has been used for measuring “out of flatness” of a rough isotropic quartz surface and creating error map for corrective figuring. By the proposed Air mist-abrasion figuring method, flatness of a rough isotropic quartz surface improved from PV= 0.4μm to PV=0.1μm without any change in surface roughness value.

Abstract: The paper presents the review of various methods of isotropic and anisotropic random surfaces of Gaussian ordinate distribution modeling. The procedure of digital simulation of one-process profile using AR methods of various degrees is presented. We analysed also FFT methods of generating random surface profiles of Gaussian ordinate distribution. The examples of using methods mentioned above for the simulation of machined profiles are given.

Abstract: For functional properties such as gliding, sealing, assembling, adhering etc. the outer layer of the surface is the functional related surface. For the functional assessment of the surface this outer layer should be used as the reference for any functional characteristic. With the existing mean line system for the assessment of roughness and waviness, the standardized characteristics do not follow this logic. However there are valid historical reasons for the acceptance of the shortcomings of the mean line system. They are e.g. the alignment of the profile, the removal of form, the assumption of a sinusoidal structure of the waviness on the surface, and the distortion of the surface by the application of the mean line filtering process. To overcome these shortcomings morphological operations have been used to establish a new developed envelope system. In order to define new parameters to characterize and specify functional properties of surfaces, a common datum is necessary. The presented method for the alignment of datums is consistent with the algorithms used to establish datums and datum systems for workpieces, where the datum is established by the location of a tangent geometrical element such as a line, plane, cylinder etc. The orientation is usually derived by the application of the minimum zone algorithm. The benefit of the assessment of the functional properties of surfaces with morphological operations will be presented for two examples.

Abstract: The reliable determination of periodic micro structures on open surfaces as they exist on involute tooth flanks gain of increasing importance. They allow conclusions from the waviness of the gear surface to the wear and running noise in gears. With the aim of determining traceable wave structures, a method has been developed at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig by which it is possible to model, realise and, especially, reliably evaluate wave-shaped structures on the flank surfaces of involute cylindrical gears.

Abstract: The implementation of the basic physical principle of Chromatic Confocal Microscopy in the field of Phase stepping interferometry (PSI) opens new opportunities for the development of an innovative surface metrology method specially dedicated to 3D nanotopography with subnanometric z axis resolution altogether with a very large measuring range: typically up to one hundred micrometers. The basic property of optical sectioning inherent to (chromatic) Confocal imaging is particularly well adapted to Phase stepping Interferometry since it automatically solves the critical and time consuming problem of phase unwrapping computation. The axial chromatic extension of the chromatic confocal setup offers a very fast and easy way to determine the height of the different elementary surfaces forming the measured object. It is then easy to carry out, for each one of those elementary surfaces, a measurement in phase shifting interferometry, at the wavelength corresponding to the altitude indicated by the confocal chromatic, in order to reach subnanometric axial resolutions. The four phases needed for implementing the phase stepping interferometric measuring procedure can be successively realized by adequate spectral shifts instead of the classical axial displacements of the reference mirror which then stands in a fixed position. Consequently this chromatic confocal phase stepping interferometer (CCPSI) has definitely no moving part, the spectral shifts being done by electrooptical means. Typical applications are MEMS and microoptics surface topography and/or roughness metrology. For this purpose we designed a new system incorporating confocal chromatic imaging and phase stepping interferometry. As a direct consequence of the optical sectioning property, this system allows measuring through any type of optical window (for example a cover glass).

Abstract: This paper describes the software gauge data for surface texture standard using the non-causal 2D auto-regressive model (A-R model). This model can provide with 3D irregular surface topography and intentional geometrical characteristics from specified surface texture parameters. The measurement area consists of a periodical combination of the generated sampling area data. The surface roughness parameters introduced from the gauge data on a defined evaluation area can be insensitive to size and location of the evaluation area size. Adequate measuring conditions to utilize the surface material measures were investigated and then the evaluation area and sampling distance for areal profiling by a stylus instrument were clarified.

Abstract: To meet the requirements of next generation Geometrical Product Specification and Verification (GPS), a surface texture information system integrated with AutoCAD is developed. The information system mainly consists of three parts: a surface texture database containing large amount of surface texture specification information, inference algorithms and interfaces with AutoCAD, so that unambiguous, explicit and complete specification for design, manufacture and verification of surface texture can be provided in AutoCAD for function assurance.

Abstract: The focus of this paper will be on comparison at the measurement of container lids between Advanced TOpometric Optical Sensor - ATOS III SO (GOM mbH) and traditional coordinate measuring machine CMM for the measurement of surfaces - Form Talysurf Series 2 (Taylor Hobson Ltd). In the paper, two kinds of measuring methods (noncontact method at ATOS and contact method at CMM Form Talysurf) and techniques will be made for comparison: digitizing measuring system based on the triangulation principle and traditional measuring systems based on the collecting of points from an object by touching it.