Surface Texture Symbols 12 Surface Texture Symbols

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.

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.

Surface Texture Terms Surface texture is the overall roughness, waviness, lay, or flaws of a surface

Surface Texture Terms Roughness height examples

Surface Texture Symbols In the past, finished surfaces were identified with finish marks, as shown here Surface texture symbols are now used instead

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

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

Surface Texture Values (e) Minimum material removal (inches or millimeters) (f) Roughness parameter other than arithmetic average

Lay Symbols Lay symbols are not required If used, there are seven options

Lay Symbols

Applying Surface Texture Symbols Surface texture symbols can be attached to: Surface “edge views” Extension lines Leader line shoulders Placed in a note

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.

Which microinch value appearing in a surface texture symbol indicates the finer finish, 8 or 1000?

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.

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.

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.

What is surface mismatch? An uneven blend on a machined surface resulting from multiple passes of a cutter.