Worst Case Tolerance and Statistical Tolerance Analysis

Worst Case Tolerance
And
Statistical Tolerance
Analysis

1.0 REVISION PAGE

REVISION DATE DESCRIPTION

1 11-17-2013 Initial Release 2 11-19-2013 Final Release
2.0 TABLE OF CONTENT

1.0 Revision Page ……………………………………………………………………………… 2
2.0 Table of Content …………………………………………………………………………… 3
3.0 Introduction ………………………………………………………………………………….4
4.0 Drawing…………………………………………………………………………………...… 5
5.0 Data and Calculation …………………………………………………………………………6
6.0 Recommendation ……………………………………………………………….…………….8

3.0 INTRODCUTION
Objective
The following report demonstrates Worst Case Tolerance Analysis, WCTA, and Statistical Tolerance Analysis, STA. The part is failing due to clearance between circuit card from male part of assembly and a metal contacting device of female part of assembly. We need use WCTA, STA to find suitable tolerance limit to eliminate so as to reduce probability of making parts outside of extreme tolerance zone.

Assembly Overview
The circuit card in male part of assembly which transmits the electrical current is inserted between metal contacting devices attached to female part of assembly to provide power to main source.

4.0 DRAWING

The following engineering drawing was used to identify necessary dimensions and its tolerances.

5.0 DATA AND CALCULATION
Nominal Clearance/ interference on Top and Bottom of Circuit Card
Dimension Number
Dimension(d)
Ti
1A
0.87
0.1
1B
1.75
0.08
2A
1.94
0.12
2B
1.13
0.12
2C
0.4
0.1

Nominal Assembly Dimension Calculation
Bottom Contact Surface
Dimension Used

Male
1B
1.75
Female
2A
1.94
Nominal Assembly dimension () = 1.94-1.75 = 0.19
Top Contact Surface
Dimension Used

Male
1A,1B
2.62
Female
2A,2C
2.34
Nominal Assembly dimension() = 2.62 - 2.34 = 0.28

Note: