锻造图纸中的符号（四）

Counterbore/Spotface - is used to indicate a counterbore or a spotface. The symbol precedes the dimension of the counterbore or spotface, with no space

—沉孔或锪平

Countersink - is used to indicate a countersink. The symbol precedes the dimensions of the countersink with no space. —埋头孔

Depth/Deep - is used to indicate that a dimension applies to the depth of a feature. This symbol precedes the depth value with no space in between.

—深度

Square - is used to indicate that a single dimension applies to a square shape. The symbol precedes the dimension with no space between. —正方形

Number of Places - the X is used along with a value to indicate the number of times a dimension or feature is repeated on the drawing. —相同的地方

Arc Length - indicating that a dimension is an arc length measured on a curved outline. The symbol is placed above the dimension. —电弧长度

Radius - creates a zone defined by two arcs (the minimum and maximum radii). The part surface must lie within this zone. —半径

之间

Between - to indicate that a profile tolerance applies to several contiguous features, letters may designate where the profile tolerance begins and ends. These letters are referenced using the between symbol (since 1994) or the word between on drawings made to earlier versions of the Standard.

统计公差

Statistical Tolerance - is the assigning of tolerances to related components of an assembly on the basis of sound statistics (such as the assembly tolerance is equal to the square root of the sum of the squares of the individual tolerances). By applying statistical tolerancing, tolerances of individual components may be increased or clearances between mating parts may be reduced. The increased tolerance or improved fit may reduce manufacturing cost or improve the product's performance, but shall only be employed where the appropriate statistical process control will be used. Therefore, consideration should be given to specifying the required Cp and /or Cpk or other process performance indices.