Illustration method of geometric tolerance
◆.Illustration method of geometric tolerance
Type of tolerance
Mark
Definition of tolerance zone
Note to illustration

Form tolerance
Straightness
When there is symbol φ in front of the numerical value
that expresses tolerance zone, it means this tolerance
zone, the area in the cylinder with diameter of t

If the tolerance frame is after the diameter of the
cylinder, it means the axial line of the cylinder
could have 0.08mm tolerance

Flatness

Tolerance zone: area enclosed by two average planes
with a distance of t

This surface must be between two parallel planes
with a distance of t
Roundness

Object plane's tolerance zone is area which
two concentric circles with a distance of t

The circumference of right-angle section of any axis
must be between two concentric circles with a distance
of t in the same plane
Cylindricity

Tolerance zone is area in which two coaxial
cylinder plane with a distance of t

Object plane must be between two coaxial cylinder
surfaces with a distance of 0.1mm
Line profile
Tolerance zone is area enclosed by two profile
lines of a circle with a diameter of t when the
center is in the theoretically correct contour line

The contour of the object in any section that is parallel with
projective surface must be between two profile lines of a
circle with a diameter of 0.04mm when the center is in the
theoretically correct contour plane.
Surface profile

Tolerance zone is area enclosed by two profile
planes of a sphere with a diameter of t when the
center is in the theoretically correct contour line

Object plane must be between two profile planes
of a sphere with a diameter of 0.02mm when the
center is in the theoretically correct contour plane
Orientation tolerance

Parallelism

When there is symbol φ in front of the numerical
value that expresses tolerance zone, this tolerance
zone is area in the cylinder with a diameter of t
that is perpendicular with the datum plane

Indication surface of indicating line arrow must be parallel
with datum surface, and be between two planes with a distance
of 0.01mm in the direction of indicating line arrow

Perpendicularity
When there is symbolφ in front of the numerical value that expresses tolerance zone ,this tolerance zone is area in the cylinder width a diameter of that is perpendicular width the datum plane.

The cylinder axis indicated by indicating line
arrow must be perpendicular with datum surface
and in the cylinder with a diameter of 0.01mm.

Angularity
Tolerance zone is area enclosed by two parallel planes with a distance of tand parallel width datum plane.


The surface indicated by indicating line arrow, must be theoretically 40°
inclined from datum plane A, and be between two parallel planes with a
distance of 0.08 in the direction of indicating line arrow.
Tolerance in position

Position

Tolerance zone is the area in a circle or sphere with a diameter
of t with theoretically correct position (hereinafter referred to
as "positive position" as the center.

The point indicated by indicating line arrow, must be in the circle
with a diameter of 0.03mm with the positive position that is 60mm
from datum straight line A and 100mm from datum straight line
B as the center.

Concentricity

When there is symbol φ in front of the numerical
value that expresses tolerance zone, this tolerance
zone is area in the cylinder with a diameter of that
is parallel with the datum axis line

The axis indicated by indicating line arrow, must be in the
cylinder with a diameter of 0.01mm with datum axial
straight line A as axis

Symmetry

Tolerance zone is the area symmetry with the
datum plane, and enclosed by two parallel
planes with a distance of "t".

The center plane indicated by indicating line arrow must be
between two parallel planes with a distance of 0.08mm and
symmetric with datum center plane A.
Vibration tolerance

Circular runout
Measure implementation surface
(measure sur face)
Tolerance surface attached
Tolerance zone is area between two concentric
circles with a distance of t in the direction of
radius and has the same center with datum axial
straight line in any measured plane perpendicular
with datum axial straight line
The vibration in the direction of cylinder plane radius indicated by indicating line arrow is in any measured plane perpendicular with datum axialstraight line when datum straight line A-B rotates a round and it will not exceed 0.1mm.

Total runout


Tolerance zone is area between two coaxial
cylinders with a distance of t in the direction of
radius and has the same axis with datum axial
straight line

The complete vibration in the direction of cylinder plane radius
indicated by indicating line arrow, when in datum straight line
A-B's rotating cylindrical part, any point on cylinder surface will
not exceed 0.1mm
The lines used in definition column of tolerance zone have the following meanings
Thick real line or dashed : form
Thick one-dot dashed: data available
Thin real line or dashed: tolerance zone
Thin one-dot dashed: center line
Thin two-dot dashed: complementary projective surface or section
Thick two-dot dashed: projection of profile to complementary projective surface or fracture surface