WHY TOLERANCE?
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Answers to the above Questions
Answers to the above Questions
Geometric Dimensioning and Tolerancin
FORM TOLERANCE
FLATNESS TOLERANCE
EXAMPLE:
Gauging / Measurement:
Flatness is can be measured using a height gauge run across the surface of the part if
only the reference feature is held parallel. You are trying making sure that any point
along the surface does not go above or below the tolerance zone. Modern CMM’s are
best for measuring the part as they can create virtual planes that the true surface profile
can be compared to. This is a 3D measurement so points must be measured across the
length and width of the part to ensure the entire surface is in tolerance. Flatness
cannot be measured by simply placing the part on a granite slab and running
height gauge over it. This would be measuring parallelism instead as you are fixing the
bottom of the part as a datum.
Final Notes: Flatness is not the same as parallelism. Parallelism uses a datum to control a
surface while flatness does not. Think of a table with two missing legs at an angle to
the floor. The table top may be within flatness tolerance but would not be parallel to the
floor.
STRAIGHTNESS TOLERANCE
EXAMPLE:
CIRCULARITY TOLERANCE
EXAMPLE:
CYLINDRICITY TOLERANCE
EXAMPLE:
ORIENTATION TOLERANCE
ANGULARITY TOLERANCE
PERPENDICULARITY TOLERANCE
PARALLELISM TOLERANCE
LOCATION TOLERANCE
POSITION TOLERANCE
CONCENTRICITY
SYMMETRY
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HAVE TO GIVE EXAMPLES TO ANGUKARITY
PERPENDICULARITY PARALISIM