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The function may be defined analytically by: Monochromatic light is essential and asje fringe sharpness and contrast depend on high reflectivity ame low absorption for the workpiece and reference mirror. Swanson, Deere 81 Co. Roughness maybe considered as superimposed on a wavy surface. These techniques generally use an optical or electrical sensor. Unnecessary restrictions may increase production costs and will mitigate the emphasis on specifications for important surfaces.
Analog meters are damped to minimize acute deflections; nevertheless, extremelyhigh and low momentary readings oftenoccur.
What is Surface Texture B for Stainless
For a roughness evaluation length of five sampling lengths, the traversing length is typically equal to at least six sampling lengths. The antialiasing filterremoves wavelengths shorter thantheNyquist wavelength prior to digitization.
It is recommended that specifications of the surface be limited to defined areas of the casting.
The level p maybe specified in several ways including: See waviness long-wavelength cutoff and wavinessevaluationlength defined in Section Proflle valley fc FIG.
The digital approximation is: However, this section does allow for the measurement of the area profiling parameters, AR, and AR, as alternatives to the traditional profiling parameters. Nominal roughness average R, grades for various manufacturing processes are listed in Table along with corresponding sampling lengths.
The nominal values given assume negligible attenuation by the stylus filter. When this is practiced, a waviness long-wavelength cutoff for the Gaussian filter must be specified. It is usually longer than the evaluation 50 length in order to keep the start and stop of the stylus scan from affecting the results.
Filter cutoff length is determined in part by the x and z aspects of the surface under evaluation. For further discussion of profile filtering, refer to Section 3. To assess the calibrated value of the B2 specimen, at least I8 evenlydistributedtracesshallbetakenon each specimen, all instrumentadjustmentsremainingconstantthroughoutthedetermination.
The surface at the bottom of the groove is assessed only over the central third of its width. The stylus dimensions limit theminimum size of the irregularities which are included in a measurement.
The z axis magnificationis the ratio of the displayed profile heightsto the actual heights of the corresponding surface features on the workpiece. This is usually determined by the capabilities of the measuring instrument by such factors as the sampling interval see para. The residual profileis thatprofilewhichis generated by internal and external mechanical disturbances as well as by devia29 3. If the skids undergo appreciable vertical displacement in movingovera surface, this displacement is subtracted from the probe motion see Fig.
The instruments permit the accurate measurement of characterization parameters for surfaces generated in production. On prior drawings whenthecutoffisnotspecified, the 0. If this force is too large, the stylus will plow through the surface irregularities instead of following their profile. The change in static measuring force in the z direction over the entire z measuring range of the pickup.
The standard roughness long-wavelengthcutoff values for the 2RC filter are listed in para. The displacementsof the stylus are linearly proportional to the heights of features contained on the surface. B1 of Appendix B.
What is Surface Texture B46.1 for Stainless
The specimens intended for overall checks of instrument performance simulate workpieces containing a wide range of crest spacings. Olear, Eastman Kodak J.
This is a key specification for a measuring instrument. The appendices shall not be considered a part of this Standard. The transfer function is: Nonworking surfaces such as those on the walls of transmission cases, crankcases, or housings seldom require any surface asne control.
b46.11 G Observations on theFiltering of SurfaceProfiles The waviness transmission characteristic in the region of the short-wavelength The form error line then is the mean line for the waviness profile.
After filtering, the measured profile is typically plotted on a graph for visual interpretation. Theymay be electroformed or made of plastic or other materiais and coated or otherwise treated to have the feel and appearance of the surfaces produced directly by a selected manufacturing process. They can also wsme equipped with an auxiliary measuring system andused as a noncontacting null sensor.
Its surface shall be b46. and flat enough not to affect the evaluation of the grooves. The FFC probe contacts the surface via its nonconductive skid. This eliminates the potential for g46.1. Area profiling instruments may be used to measure AR, and AR, provided the lateral resolution andthe sampling length or alternatively, the sampling area are indicated for each measurement. Analytically, Ris given by: Criteria for selection of surface qualities and information on instrument techniques and methods of producing, controlling, and inspecting surfaces are included in the other sections and in the appendices.