Machinery's Handbook, 31st Edition
828 ISO Surface Texture Symbology Examples Surface roughness for the chamfer is produced by any material removal process to one unilateral upper limit specification, Ra = 2.5 m m. It is to the default “16%-rule,” default transmission band and default evaluation length (5 × l c) (ISO 3274). There is no lay requirement.
Rz 50
2 x 45
A
A
Fig. 13. Fig. 14. Example 7: Surface texture symbology may be applied to extended extension lines or on extended projection lines, Fig. 14 . All feature surface roughness specifications shown are obtainable by any material removal process and are single unilateral upper limit specifica tions, respectively: Ra = 1.5 m m, Ra = 6.2 m m and Rz = 50 m m. All are to “16%-rule” default, default transmission band and default evaluation length (5 × l c). There is no lay requirement for any of the three. Example 8: Surface texture symbology and dimensions may be combined on leader lines, as in Fig. 15 . The feature surface roughness specifications shown are obtainable by any material removal process and are single unilateral upper limit specifications, respectively: Rz = 1 m m, to the default “16%-rule,” default transmission band and default evaluation length (5 × l c). There is no lay requirement.
Fe/Cr50
Ground Rz 6.5
Rz 1.7
14
Fig. 15. Fig. 16. Example 9 : Symbology can be used for dimensional information and surface treatment . Fig. 16 illustrates three successive steps of a manufacturing process. The first step is a single unilateral upper limit Rz = 1.7 m m to the default “16%-rule,” default evaluation length (5 × l c) and default transmission band. It is obtainable by any material removal process, with no lay characteristics specified. Step two, indicated with a phantom line over the whole length of the cylinder, has no surface texture requirement other than chromium plating. The third step is a single unilateral upper limit of Rz = 6.5 m m applied only to the first 14 mm of the cylinder surface. The default “16%-rule” applies as does default evaluation length (5 × l c) and default transmission band. Material removal is to be by grinding, with no lay characteristics specified.
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