In production, if we misunderstand the geometric tolerances marked on the drawings, the processing analysis and processing results will deviate from the requirements, and even bring serious consequences. Today, let us systematically understand the 14 geometric tolerances.

01 Straightness

Straightness, also known as the degree of straightness, indicates the condition in which the actual shape of the straight line element on the part remains an ideal straight line. The straightness tolerance is the maximum variation allowed for the actual line to the ideal straight line.

Example 1: In a given plane, the tolerance zone must be in the area between two parallel lines with a distance of 0.1mm. Example 2: Add the symbol Φ before the tolerance value, then the tolerance zone must be within the area of the cylindrical surface with a diameter of 0.08mm.

  02 Flatness

Flatness, also known as the degree of flatness, indicates the actual shape of the plane elements of a part and the condition of maintaining an ideal plane. Flatness tolerance is the maximum allowable variation of the actual surface from the ideal plane.