Mx Surface Texture Parameters
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Mx Surface Texture Parameters

© Copyright 2022 by Zygo Corporation. All rights reserved. Information in this document is subject to change without notice. No liability is assumed with respect to the use of the information contained in this documentation or software, or for damages in connection with this information. OMP-0608D August 2022

Standards ZYGO is an industrial leader in surface texture metrology and complies with numerous international standards, including the following: ANSI/ASME B46.1 - Surface Texture (Surface Roughness, Waviness and Lay) ISO 4287 - Geometric products specifications (GPS) - Surface texture: Profile method - Terms, definitions and surface texture parameters ISO 4288 - Geometric products specifications (GPS) - Surface texture: Profile method - Rules and procedures for the assessment of surface texture ISO 13565 - Geometric products specifications (GPS) - Surface texture: Profile method - Surfaces...

Surface Texture- The topography of a surface composed of certain deviations that are typical of the real surface. It includes roughness and waviness. Lay- direction of finish pattern. Form- general shape of the surface (inaccurate machine, stressed part). Waviness- widely spaced irregularities (vibration, chatter). Roughness- closely spaced irregularities (cutting tool marks, grit of grinding wheel). Filtering A filter cutoff is used to separate the roughness and waviness components of a surface. Shorter wavelengths become part of the roughness data; longer wavelengths are part of the...

Profile ISO Parameters Profile ISO Height Parameters These are amplitude results based on ISO 4287. Arithmetic mean deviation of the roughness profile defined on the sampling length. Ra does not indicate the spatial frequency of the irregularities or the shape of the profile. Ra is meaningful for measuring surfaces that are sand blasted, milled, or polished. Kurtosis of the roughness profile. It is a measure of the randomness of heights, and of the sharpness of a surface. A perfectly random surface has a value of 3; the farther the result is from 3, the less random and more repetitive the...

Profile ISO Height Parameters (continued) Rpm Mean peak profile height. The mean peak height based on one peak per sampling length. The single highest peak is found in five sampling lengths and then averaged. Skewness of the roughness profile. It is a measure of symmetry of the profile about the mean line. An Rsk value of 0 depicts normal distribution about the average line. Positive values correspond to high peaks spread on a regular surface while negative values are found on surfaces with openings and scratches. Mean valley profile depth. The mean valley depth based on one peak per...

Average peak-to-valley profile roughness. The average peak-to-valley roughness based on one peak and one valley per sampling length. The single largest deviation is found in five sampling lengths and then averaged. Profile ISO Functional (Material Ratio) Parameters These 2D ISO results evaluate the plateau structure of the surface. These are suitable for evaluation of adhesion performance, surface treatability, wear resistance, and lubrication performance. Profile functional parameters are based on ISO 13565. Peak area defined by Rpk. Valley area defined by Rvk. Peak Material Component. The...

Profile ISO Material Ratio Parameters (continued) Rk Midpoint The middle point of the Rk region; it is an absolute height. Reduced Peak Height. Peak height above the core roughness. During a running-in operation, Rpk is the nominal height of the material that may be removed. The threshold between the Rpk and Rk regions; it is an absolute height. Reduced Valley Depth. Valley depth below the core roughness. Rvk impacts a surface’s ability to trap debris and retain lubricant. The threshold between Rk and Rvk regions; it is an absolute height. Height (or depth) at profile material ratio control...

Profile ISO Hybrid Parameters These are 2D ISO spacing parameters, typically useful for surfaces having periodic or pseudo-periodic motifs, such as turned or structured surfaces. The average spacing between local peaks over the evaluation length. A local peak is the highest point between two adjacent minima. The average spacing between peaks at the mean line over the evaluation length. A peak is the highest point between an upwards and downwards crossing of the mean line. It is calculated by summing all the peak spacing and dividing by the number of spaces. Profile Parameters Profile Area...

Profile Area Parameters (continued) Area Below Area Below is the area of the profile data below the mean. Instrument calibration is required for this result. The mean is the best fit surface to the data. Area Net is the overall area of the profile data. It is equal to the Area Above minus the Area Below. Instrument calibration is required for this result. Area Total Area Total is the sum of the Area Above and the Area Below the mean of the profile data. Instrument calibration is required for this result. The mean is the best fit surface to the data. Profile Dimension Parameters These are...

Profile Hybrid Parameters Correlation Length Correlation Length is the length along the xaxis where the Autocovariance (ACF) function first crosses zero. Autocovariance is used to determine the periodicity of a surface; it shows the dominant spatial frequencies along a cross section of the test surface. ACF is a measure of “selfsimilarity” of a profile - the extent to which a surface waveform pattern repeats. If the surface is random, the plot drops rapidly to zero. If the plot oscillates around zero in a periodic manner, then the surface has a dominant spatial frequency. Surface/Profile...

Surface/Profile Height Parameters (continued) Mean The arithmetic average of a set of values. It is calculated by summing the data and dividing by the number of points. The mean is often quoted along with the standard deviation- the mean describes the central location of the data, and the standard deviation describes the spread. Peak is the maximum distance between the center line and the highest peak point within the sample. The center line is defined as the best-fit surface selected with the remove function. Peak is the value of the highest data point. The x-axis location in camera...