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Tolerance Stack-Up Analysis

The document discusses tolerance stack-up analysis and calculating virtual and resultant conditions. It defines maximum material condition (MMC) and least material condition (LMC) as the maximum and minimum amount of material within size limits. Examples are given to demonstrate calculating equal bilateral tolerance from MMC/LMC and finding the mean. The boundaries of virtual condition and resultant condition are defined as the collective effects of size limits, geometric tolerance, and bonus tolerance. Formulas are provided to calculate virtual and resultant conditions for holes and pins.

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Praveen Shandige
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2K views22 pages

Tolerance Stack-Up Analysis

The document discusses tolerance stack-up analysis and calculating virtual and resultant conditions. It defines maximum material condition (MMC) and least material condition (LMC) as the maximum and minimum amount of material within size limits. Examples are given to demonstrate calculating equal bilateral tolerance from MMC/LMC and finding the mean. The boundaries of virtual condition and resultant condition are defined as the collective effects of size limits, geometric tolerance, and bonus tolerance. Formulas are provided to calculate virtual and resultant conditions for holes and pins.

Uploaded by

Praveen Shandige
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Rev.

1/2010 Tolerance Stack-Up Analysis


Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis
Finding the mean:
Calculate the sum and the difference between the
MMC and LMC and divide each by two

• Maximum Material Condition (MMC): The


maximum material condition of a feature of size
is the maximum amount of material within the
stated limits of size. For example, the maximum
shaft diameter or the minimum hole diameter.

• Least Material Condition (LMC): The least


material condition of a feature of size is the least
amount of material within the stated limits of
size. For example, the minimum shaft diameter
or the maximum hole diameter.
Tolerance Stack-Up Analysis
Example – Limit dimension
Ø20 – 22

MMC/LMC 22 22
LMC/MMC + 20 – 20

2 ) 42 )
2 2
21 1

Equal Bilateral
Tolerance (±) of part 21 ± 1
Tolerance Stack-Up Analysis
Example – Unequal bilateral tolerance
+1
Ø50
–3

MMC/LMC 51 51
LMC/MMC + 47 – 47

2) 98 )
2 4
49 2

Equal Bilateral
Tolerance (±) of part 49 ± 2
Tolerance Stack-Up Analysis
Boundaries
• Virtual Condition
The virtual condition of a feature specified at MMC is a
constant boundary generated by the collective effects of
the MMC limit of size of a feature and the specified
geometric tolerance.
Virtual condition calculations:
External Features (Pin) Internal Features (Hole)

MMC MMC
Plus Geo. Tol. @ MMC Minus Geo. Tol. @ MM
Equals Virtual Condition Equals Virtual Condition

Tolerance Stack-Up Analysis


• Resultant Condition
The resultant condition of a feature specified at MMC is
a variable boundary generated by the collective effects
of the LMC limit of size of a feature, the specified
geometric tolerance, and any applicable bonus tolerance.
Extreme resultant condition calculations:
External Features (Pin) Internal Features (Hole)

LMC LMC
Minus Geo. Tol. @ MMC Plus Geo. Tol. @ MMC
Minus Bonus Tolerance Plus Bonus Tolerance
Equals Result. Condition Equals Result. Condition

Tolerance Stack-Up Analysis


Tolerance Stack-Up Analysis
Virtual and Resultant Conditions, Hole
VC/RC 54 54
RC/VC + 48 – 48

)
2 102 )
2 6
51 3

Equal Bilateral
Tolerance (±) of part 51 ± 3

Tolerance Stack-Up Analysis


Tolerance Stack-Up Analysis
Virtual and Resultant Conditions, Pin
VC/RC 48 48
RC/VC + 42 – 42

)
2 90 2 ) 6
45 3

Equal Bilateral
Tolerance (±) of part 45 ± 3

Tolerance Stack-Up Analysis


Tolerance Stack-Up Analysis
Tolerance Stack-Up Analysis

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