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Permission granted to reproduce for educational use only.
• Explain common terms related to surface quality and surface texture symbols.
• Identify and interpret the components of surface texture symbols.
• Identify lay symbols used in surface texture symbols.
Permission granted to reproduce for educational use only.
• Describe the units used by various values within surface texture symbols.
• Explain standard practices for applying surface texture symbols on a print.
• Identify special designations related to surface quality that may appear on a print.
Permission granted to reproduce for educational use only.
Surface Texture Terms
• Surface texture is the overall roughness, waviness, lay, or flaws of a surface
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Surface Texture Terms
• Roughness height examples
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Surface Texture Symbols
• In the past, finished surfaces were identified with finish marks, as shown here
• Surface texture symbols are now used instead
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Surface Texture Symbol
• A—Basic surface texture symbol• B—Material removal is required by machining• C—Indicates a minimum amount that must be
removed• D—Material removal is prohibited• E—Horizontal bar to help locate parameters and
values
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Surface Texture Values
• (a) Average roughness value (in microinches or micrometers)
• (b) Optional production method (i.e., MILL or GRIND)
• (c) Roughness cutoff or sampling length• (d) Optional lay symbol
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Surface Texture Values
• (e) Minimum material removal (inches or millimeters)
• (f) Roughness parameter other than arithmetic average
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Lay Symbols
• Lay symbols are not required• If used, there are seven options
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Applying Surface Texture Symbols
• Surface texture symbols can be attached to:– Surface “edge views”– Extension lines– Leader line shoulders– Placed in a note
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• What is the difference between surface texture and surface roughness?
Surface texture is the overall roughness, waviness, lay, or flaws of a surface, while surface roughness is the fine irregularities in the surface texture.
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• Which microinch value appearing in a surface texture symbol indicates the finer finish, 8 or 1000?
8
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• When the symbol appears in the surface texture symbol, what does it indicate?
It is a lay symbol that means the lay is perpendicular to the edge view line to which the texture symbol is applied.
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• If the value .06 appears under the horizontal bar in a surface texture symbol, what does this mean?
It specifies a roughness cutoff, or sampling length, of .06 inches.
Permission granted to reproduce for educational use only.
• List three methods that may be used to place surface texture symbols on a drawing in order to reduce clutter in a view.
Place the symbol on an extension line or leader line to the edge view of the feature or include the symbol in a note.