fit design with manufacturing tolerances

FitDesignAnalyst

Copyright 2009 David Denmat

TM

Tutorial 3 – Fit Design with Manufacturing Tolerances

Tutorial 3:

Fit Design

with

Manufacturing

Tolerances

FitDesignAnalyst


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Given: A Ø3/4 nominal Shaft is purchased with a +.003/-.001 tolerance

specification.

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specification.

The Shaft is to slide in a Hole with a .001 allowance (minimum clearance).

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specification.


The Hole diameter will be machined with a .002 tolerance.

FitDesignAnalyst


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specification.

Find: Design the Hole size that will achieve the above assembly requirements.



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specification.




Note that the Basic Hole System is not applicable for this design.

FitDesignAnalyst


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specification.





Note the precision (the number of decimal places) of the given tolerances.

In this design, the precision is three decimal places (.XXX).

FitDesignAnalyst


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specification.





Note the precision (the number of decimal places) of the given tolerances.

In this design, the precision is three decimal places (.XXX).

PRECISION

3-PLACE .XXX

Select a 3-place decimal from the Precision pull-down at the top of the screen.

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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT

Given: A Ø3/4 nominal Shaft is purchased with a +.003/-.001 tolerance specification.





FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT

Enter the known information, in any order desired.






FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Starting with the Shaft, select the lower (small) Shaft limit…






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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the Shaft lower limit…






FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the Shaft lower limit…






. 7 4 9

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT







. 7 4 9

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Select the Shaft upper (large) limit…






. 7 4 9

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the Shaft upper (large) limit…






. 7 4 9

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the Shaft upper (large) limit…






. 7 4 9 . 7 5 3

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT

Intermediate results will be automatically posted.






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT







. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the allowance…






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT


Enter the allowance…






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

Intermediate results will be automatically posted.

. 7 5 4

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

. 7 5 4


FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

. 7 5 4


Enter the Hole tolerance…

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

. 7 5 4

Enter the Hole tolerance…

. 0 0 2

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1. 0 0 4

. 0 0 1

. 7 5 4 . 0 0 2

All remaining dimensional fit solution information for the given design requirements

will be computed and posted...

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2


will be computed and posted.

. 0 0 1

. 7 5 6 . 7 5 5 0

. 0 0 4 0. 0 0 6CLEARANCE CLEARANCE MEAN CLEARANCE

FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0

. 0 0 4 0. 0 0 6

The Hole size design limit dimensions.

CLEARANCE CLEARANCE MEAN CLEARANCE

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0

. 0 0 4 0. 0 0 6

The Hole size design mean dimension.


FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0

. 0 0 4 0. 0 0 6

The Shaft size design mean dimension.


FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0

. 0 0 4 0. 0 0 6

The Fit limits.


FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0


The System Tolerance.

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2



. 0 0 1

. 7 5 6 . 7 5 5 0


The resulting Mean Fit for the design.

FitDesignAnalyst


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LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2

. 0 0 1

. 7 5 6 . 7 5 5 0


FitDesignAnalyst


TM


LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT






. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2

Select Print Command for hard-copy documentation.

. 0 0 1

. 7 5 6 . 7 5 5 0


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FitDesignAnalyst


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Save the file for digital storage and retrieval.

LIMITS

LARGE

SMALL

+– –

HOLE

SHAFT

TOLERANCES MEANS

SMALL

LARGE

LARGE SMALLFIT

. 7 4 9 . 7 5 3 . 7 5 1 0. 0 0 4

. 0 0 7

. 7 5 4 . 0 0 2

. 0 0 1

. 7 5 6 . 7 5 5 0







FitDesignAnalyst


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Draw the Hole and Shaft

geometry in CAD to their

mean dimensions…






FitDesignAnalyst


TM


Draw the Hole and Shaft

geometry in CAD to their

mean dimensions…






For reference,

mean dimensions

are displayed at

maximum precision.

FitDesignAnalyst


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Apply the tolerances to

the mean dimensions…






FitDesignAnalyst


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Apply the tolerances to the

mean dimensions….






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Apply the tolerances to the

mean dimensions…

to post the limit dimensions.






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Assemble “to the mean”.

FitDesignAnalyst


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Assemble “to the mean”.

For reference,

mean dimensions

are displayed at

maximum precision.

FitDesignAnalyst


TM







Note that the “mean fit”

is achieved. For reference,

mean dimensions

are displayed at

maximum precision.

FitDesignAnalyst


TM







For reference,

mean dimensions

are displayed at

maximum precision.

FitDesignAnalyst


TM







End.

fit design with manufacturing tolerances

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