Toler oleran ance ce Analy Analysi sis s and
Stack-u Stack-up p Toleran olerances ces Aditi Consultancy Servic Services es #2, ‘ANANDA’, 19th Cross, 24th Main J P Nagar 5th Phase, Bangalore-560078 Phone/Fax: 080-26580711; 080-26580711; Mobile: 9449612671
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TOLERANCES • BILATERAL TOLERANCE • EQUAL BILATERAL • UNEQUAL BILATERAL
• UNILATERAL TOLERANCE • LIMIT TOLERANCE
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TOLERANCES • BILATERAL TOLERANCE • EQUAL BILATERAL • UNEQUAL BILATERAL
• UNILATERAL TOLERANCE • LIMIT TOLERANCE
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Bilateral Tolerance A bilateral tolerance is a tolerance which is expressed as plus and minus values, where neither is zero, to denote permissible variations in both both directions from the specified size.
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Unilateral Tolerance A unilateral tolerance is one which applies only in one direction from the specified size, so that the permissible variation in the other direction is zero.
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Limit Dimensioning
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Limits of Size
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Limits of Size
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Classification of Tolerances Tolerances
Dimensional
Size
Geometric
Form
Orientation
Location
Run-out
Profile
Straightness
Parallelism
Position
Circular
Line
Flatness
Perpendicularity
Concentricity
Total
Surface
Circularity
Angularity
Symmetry
Cylindricity
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Fuel Pump
Fuel Pump
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Geometrical Variations
Geometry, GD&T...
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Assembly, FEA, Wear ...
Assembly Problems
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Dimension this part with a tolerance of ± 0.05mm between any two surfaces
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Change the design such that variation in distance between any two surfaces is not more than ±0.1mm
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LIMITS and FITS
Material Conditions • Maximum Material Condition (MMC) That condition where a feature of size contains the maximum amount of material within the stated limits of size. Example: maximum shaft size and minimum hole size.
• Least Material Condition (LMC) That condition where a feature of size contains the least amount of material within the stated limits of size. Example: minimum shaft size and maximum hole size.
Shaft Size Limits
Hole Size Limits
Taylor’s Principle
FITS
Clearance Fit
Transition Fit
Interference Fit
Deviations
Deviations
+ 0.3
Hole Tolerance
0.2 + 0.1
φ 12 - 0.1 - 0.10 - 0.17
0.07
Shaft Tolerance
+ 0.1
FITS
INTERFERENCE FITS
p m
H
e
f
g
h
n
k j TRANSITION FITS
d c b
CLEARANCE FITS
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Types of Fits Extra Loose Running Fit Loose Running Fit Easy Running Fit Running Fit Close Running Fit Slide Fit Push Fit Wringing Fit – Easy Keying Fit Light Keying Fit Drive Fit Light Press Fit Press Fit Heavy Press Fit
ISO SYSTEM OF TOLERANCES SHAFT
ISO SYSTEM OF TOLERANCES HOLE
Fundamental Deviation Fundamental deviations are represented by the following letter symbols: Type of Fit
Hole
Shaft
Clearance
A, B, C, D, E, EF,F,FG, G & H
a, b, c, d, e, ef, f, fg, g & h
Transition
J, JS, K, M & N
j, js, k, m & n
Interference
P, R, S, T, U, V, p, r, s, t, u, v, x, X, Y, Z, ZA, ZB & ZC y, z, za, zb & zc
