ISO Surface Finish Standards ISO Surface Finish Standards Machinery's Handbook, 31st Edition
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ISO surface finish standards are comprised of numerous individual standards that, taken as a whole, form a set of standards roughly comparable in scope to American Na- tional Standard ANSI/ASME Y14.36. ISO Surface Finish (ISO 1302).— The primary standard dealing with surface finish, ISO 1302:2002 is concerned with the methods of specifying surface texture symbology and additional indications on engineering drawings. The parameters in ISO surface finish standards relate to surfaces produced by abrading, casting, coating, cutting, etching, plas- tic deformation, sintering, wear, erosion, and some other methods. ISO 1302 defines how surface texture and its constituents, roughness, waviness, and lay, are specified on the symbology. Surface defects are specifically excluded from consider ation during inspection of surface texture, but definitions of flaws and imperfections are discussed in ISO 8785.
Position of complementary requirements: all values in millimeters
Basic symbol for surface under consideration or to a specification explained elsewhere in a note. The textual indication is APA (any process allowed) Basic symbol for mate- rial removal is required, for example machining. The textual indication is MRR (material removal required) Basic symbol with all round circle added to indicate the specifica- tion applies to all sur- faces in the view shown in profile (outline) Basic symbol where material removal is not permitted. The textual indication is NMR (no material removed)
Manufacturing method, treatment, coating or other requirement
Machining allowance (as on casting and forgings)
c
Single texture parameter with numerical limit and band and/or sampling length
a
e
d b
Lay and orientation
Second texture parameter with numerical limit and band and/or sampling length. For a third or subsequent texture requirement, positions “ a ” and “ b ” are moved upward to allow room
d '
c a d b
x '
x
h
e
3.5 5
Text height h (ISO 3098-2)
2.5
7
10 14 20
Line width for symbols d and d '
0.25 0.35 0.5 0.7 1
1.2 2
x
Height for segment
3.5 5
7
10 14 20 28
x '
Height for symbol segment
7.5 10.5 15 21 30 42 60
Fig. 1. ISO Surface Finish Symbols Differences Between ISO and ANSI/ASME Surface Finish Symbology: ISO 1302, like ANSI/ASME Y14.36-2018, is not concerned with luster, appearance, color, corrosion resistance, wear resistance, hardness, sub-surface microstructure, surface integrity, or many other characteristics that may govern considerations in specific applications. Visually, ISO 1302 surface finish symbols are similar to the ANSI/ASME symbols; however, with the release of the 2002 edition, the indication of some of the parameters has changed when compared to ANSI/ASME Y14.36. The proportions of the symbol in
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