ISE 370 TOLERANCES

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ISE 370TOLERANCES
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Performance Factors gt Dimensions Linear A
ngular gt Surfaces
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ToleranceAllowable Variation from the
DimensionDifference Between the Maximum
Minimum Limits
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Tolerances Techniques gt Bilateral gt
Unilateral gt Limit Dimension
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Geometric Attributes gt Straightness gt
Flatness gt Parallelism gt Roundness,
Circularity gt Concentricity gt Squareness gt
Angularity
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StraightnessThe degree to which a part feature
such as a line of axis is a straight
line.Symbol
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FlatnessThe extent to which all points on a
surface lie in a single plane.Symbol
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ParallelismThe degree to which all points such
as a surface are equidistant from a reference
plane or line. Symbol
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Roundness, CircularityThe degree to which all
points on the intersection of a hole a plane
perpendicular to the axis of revolution are
equidistant from the axis.Symbol
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ConcentricityThe degree which 2 or more part
features, such as a cylindrical surface a
circular hole have a common axis.Symbol
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PerpendicularityThe degree which all points on
a surface or line are 90 degrees from a reference
plane or line.Symbol
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AngularityThe extent to which a surface is at
a specified angle relative to a reference
surface.Symbol
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Three Types of Fits gt Clearance gt
Interference Force gt Transition
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Surface TextureDefined By gt Roughness gt
Waviness gt Lay gt Flaw
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Max Waviness Height Max Waviness Width
0.002 0.5 0.030
(Cutoff Length) 63 Lay Symbol
32 0.010 (Max Roughness Spacing)Max
Average Roughness Min Average Roughness
(Micro-Inches) Surface Texture

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Loss of Quality Represents Loss to
ProducergtCost of RepairsgtCost of RejectsgtCost
of Customer Dissatisfaction Loss to
SocietygtCost of RepairsgtCost of OperationgtCost
of Maintenance
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Quadratic Loss Function LSL USLLoss
Target x (Value) Loss k (x
Target)2 k Cost Coefficient Losssite /
(Toleranceold)2
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Window Frame ExampleFind width toleranced1
fall out dimensiond2 too long dimensiond
(target) mean of d1 d2 ½ (d1 d2)
Convention Tolerance T0 ½ (d2 - d1) Customer
Tolerance Range w d /- T0
Slats d d1 d2
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Loss FunctionL(width) k (width d)2k
Cost(site) / T02 (New Tolerance) TN width
d Cost(mfg) Cost(site)/T02 TN2
New Tolerances TN v Cost(mfg) / Cost(site)
T0
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Tolerance Summary gt Products processes should
be designed so that they are robust to
external sources of variability.gt Experimental
design methods are an engineering tool to
help accomplish this objective.gt Operation
on-target is more important than conformance
to specifications.