Fast algorithm for Morphological FiltersLou, Shan; Jiang, Xiangqian; Scott, Paul J
doi: 10.1088/1742-6596/311/1/012001pmid: N/A
In surface metrology, morphological filters, which evolved from the envelope filtering system (E-system) work well for functional prediction of surface finish in the analysis of surfaces in contact. The naive algorithms are time consuming, especially for areal data, and not generally adopted in real practice. A fast algorithm is proposed based on the alpha shape. The hull obtained by rolling the alpha ball is equivalent to the morphological opening/closing in theory. The algorithm depends on Delaunay triangulation with time complexity O(nlogn). In comparison to the naive algorithms it generates the opening and closing envelope without combining dilation and erosion. Edge distortion is corrected by reflective padding for open profiles/surfaces. Spikes in the sample data are detected and points interpolated to prevent singularities. The proposed algorithm works well both for morphological profile and area filters. Examples are presented to demonstrate the validity and superiority on efficiency of this algorithm over the naive algorithm.
Realization and calibration of the "Isara 400" ultra-precision CMMWiddershoven, I; Donker, R L; Spaan, H A M
doi: 10.1088/1742-6596/311/1/012002pmid: N/A
This paper presents the realization of the Isara 400 ultra-precision 3D coordinate measuring machine, which features a measuring volume of 400 × 400 × 100 mm and a volumetric (3D) measurement uncertainty of 100 nm (2). In order to achieve these challenging specifications, specific calibration strategies need to be applied, such as the calibration of flatness and out-of-squareness of the system's mirror table. In addition, a newly developed ultra-precision tactile probe system is described, featuring a probe tip with a diameter of 70 m; results of the 3D sensitivity calibration of this probe are presented.
Optical Measurement of Micro Cutting ToolsHelmli, F; Danzl, R; Scherer, S
doi: 10.1088/1742-6596/311/1/012003pmid: N/A
We present an optical measurement device for the complete 3D measurement of very small micro cutting tools with diameters down to 100m and below. Such micro tools can be hardly measured by conventional devices such as tactile systems due to their complex geometry and small dimensions. The used optical device is based on the Focus-Variation principle which combines the small depth of focus of an optical system with vertical scanning to provide topographical and color information from the variation of focus. Full 360° measurements of the tools are automatically measured in a two step procedure. First, single measurements are performed from different directions all around the specimen with the aid of a motorized rotation unit. Then all single datasets are automatically aligned and merged to a full 360° dataset. Various measurement results are presented for milling cutters and drills including tools with diameters in the range of about 50m. From the measured tools various parameters can be obtained including the major diameter, the core diameter or various angles. Additionally roughness measurements are provided on small cutting tools showing the versatility of the system for both form and roughness measurements.
A quantitative method to estimate high gloss polished tool steel surfacesRebeggiani, S; Rosén, B -G; Sandberg, A
doi: 10.1088/1742-6596/311/1/012004pmid: N/A
Visual estimations are today the most common way to assess the surface quality of moulds and dies; a method that are both subjective and, with today's high demands on surfaces, hardly usable to distinguish between the finest surface qualities. Instead a method based on non-contact 3D-surface texture analysis is suggested. Several types of tool steel samples, manually as well as machine polished, were analysed to study different types of surface defects such as pitting, orange peel and outwardly features. The classification of the defect structures serves as a catalogue where known defects are described. Suggestions of different levels of 'high surface quality' defined in numerical values adapted to high gloss polished tool steel surfaces are presented. The final goal is to develop a new manual that can work as a 'standard' for estimations of tool steel surfaces for steel producers, mould makers, polishers etc.
Calibration of the geometrical characteristics of areal surface topography measuring instrumentsGiusca, C L; Leach, R K; Helery, F; Gutauskas, T
doi: 10.1088/1742-6596/311/1/012005pmid: N/A
The use of areal surface topography measuring instruments has increased significantly over the past ten years as industry starts to embrace the use of surface structuring to affect the function of a component. This has led to a range of areal surface topography measuring instruments being developed and becoming available commercially. For such instruments to be used as part of quality control during production, it is essential for them to be calibrated according to international standards. The ISO 25178 suite of specification standards on areal surface topography measurement presents a series of tests that can be used to calibrate the metrological characteristics of an areal surface topography measuring instrument. Calibration artefacts and test procedures have been developed that are compliant with ISO 25178. The material measures include crossed gratings, resolution artefacts and pseudorandom surfaces. Traceability is achieved through the NPL Areal Instrument a primary stylus-based instrument that uses laser interferometers to measure the displacement of the stylus tip. Good practice guides on areal calibration have also been drafted for stylus instruments, coherence scanning interferometers, scanning confocal microscopes and focus variation instruments.
Characterization of nano-structured surfaces by EUV scatterometryScholze, F; Kato, A; Laubis, C
doi: 10.1088/1742-6596/311/1/012006pmid: N/A
Scatterometry in the UV and the VIS is widely used for the inspection of nano-structured surfaces in, e.g. quantitative wafer metrology in the semiconductor industry. As the structures become progressively smaller, ever fewer propagating diffraction orders exist. Consequently, these few orders do not carry enough information about the structure any more. Particularly the reconstruction of structures without detailed a priori knowledge becomes impossible due to this lack of information. The Physikalisch-Technische Bundesanstalt (PTB) has developed extreme UV (EUV) scatterometry using its EUV reflectometry facility at the electron storage ring BESSY II. The short wavelength of EUV at around 13 nm is advantageous since it provides more propagating diffraction orders compared to the longer wavelength radiation. The short wavelength also increases the sensitivity to small structural features, particularly roughness. We present the application of EUV scatterometry for the characterization of absorber lines with a trapezoidal cross section on semiconductor photo masks and for the characterization of ultra-smooth surfaces of EUV multilayer mirrors. It is shown that structure roughness significantly impacts the scattered diffraction intensities from structured surfaces and must be included in the structure reconstruction algorithms using inverse modelling by FEM. Estimates for the changes in reconstructed geometrical parameters induced by roughness are presented.
Machine integrated optical measurement of honed surfaces in presence of cooling lubricantSchmitt, R; König, N; Zheng, H
doi: 10.1088/1742-6596/311/1/012007pmid: N/A
The measurement of honed surfaces is one of the most important tasks in tribology. Although many established techniques exist for texture characterization, such as SEM, tactile stylus or white-light interferometry, none of them is suited for a machine integrated measurement. Harsh conditions such as the presence of cooling lubricant or vibrations prohibit the use of commercial sensors inside a honing machine. Instead, machined engine blocks need time-consuming cleaning and preparation while taken out of the production line for inspection. A full inspection of all produced parts is hardly possible this way. Within this paper, an approach for a machine-integrated measurement is presented, which makes use of optical sensors for texture profiling. The cooling lubricant here serves as immersion medium. The results of test measurements with a chromatic-confocal sensor and a fiber-optical low-coherence interferometer show the potential of both measuring principles for our approach. Cooling lubricant temperature and flow, scanning speed and measurement frequency have been varied in the tests. The sensor with best performance will later be chosen for machine integration.
Effect of measurement conditions on three-dimensional roughness values, and development of measurement standardFabre, A; Raynaud, S; Brenier, B
doi: 10.1088/1742-6596/311/1/012008pmid: N/A
Friction or corrosion behaviour, fatigue lifetime for mechanical components are influenced by their boundary and subsurface properties. The surface integrity is studied on mechanical component in order to improve the service behaviour of them. Roughness is one of the main geometrical properties, which is to be qualified and quantified. Components can be obtained using a complex process: forming, machining and treatment can be combined to realize parts with complex shape. Then, three-dimensional roughness is needed to characterize these parts with complex shape and textured surface. With contact or non-contact measurements (contact stylus, confocal microprobe, interferometer), three-dimensional roughness is quantified using the calculation of pertinent parameters defined by the international standard PR EN ISO 25178-2:2008. An analysis will identify the influence of measurement conditions on three-dimensional parameters. The purpose of this study is to analyse the variation of roughness results using contact stylus or optical apparatus. The second aim of this work is to develop a measurement standard well adapted to qualify the contact and non-contact apparatus.
Development of measurement standards for verifying functional performance of surface texture measuring instrumentsFujii, A; Suzuki, H; Yanagi, K
doi: 10.1088/1742-6596/311/1/012009pmid: N/A
A new measurement standard is proposed for verifying overall functional performance of surface texture measuring instruments. Its surface is composed of sinusoidal surface waveforms of chirp signals along horizontal cross sections of the material measure. One of the notable features is that the amplitude of each cycle in the chirp signal form is geometrically modulated so that the maximum slope is kept constant. The maximum slope of the chirp-like signal is gradually decreased according to movement in the lateral direction. We fabricated the measurement standard by FIB processing, and it was calibrated by AFM. We tried to evaluate the functional performance of Laser Scanning Microscope by this standard in terms of amplitude response with varying slope angles. As a result, it was concluded that the proposed standard can easily evaluate the performance of surface texture measuring instruments.
An expert system to characterize the surface morphological properties according to their functionalitiesBigerelle, M; Mathia, T; Iost, A; Correvits, T; Anselme, K
doi: 10.1088/1742-6596/311/1/012010pmid: N/A
In this paper we propose a new methodology to characterize the morphological properties of a surface in relation with its functionality (tribological properties, surface coating adhesion, brightness, wettability). We create a software based on experimental design and surface profile recording. Using an appropriate database structure, the roughness parameters are automatically computed at different scales. The surface files are saved in a hard disk directory and roughness parameters are computed at different scales. Finally, a statistical analysis system proposes the roughness parameter (or the pair of roughness parameters) that better describe(s) the functionality of the surface and the spatial scales at which the parameter(s) is (are) the more relevant.