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TOLERANCE STACK-UP ANALYSIS
[for Plus and Minus and Geometric Tolerancing]
per the ASME Y14.5-2009 and 1994 Standards

James D. Meadows
300 pages, illustrated, color, 2nd Edition, published 2010 / $89.00

ISBN: 978 0971 440142

This text-workbook/answerbook explains the process of Tolerance Stack-Up Analysis for assemblies using both plus and minus and geometric tolerances. It explains pertinent aspects of Geometric Dimensioning and Tolerancing, then proceeds to teach a sound, logical, mathematically-reliable methodology for calculating tolerance stack-ups. This text is comprehensive, yet very easy to understand and follow from lesson to lesson - by James D. Meadows. 

This second edition is easier to understand, includes more discussion on what can go wrong, shows how to tell right from wrong stack-up routes, includes more on statistical analysis, 

reads smoother and adds information that eases the learning process.  The terminology in this revision has been updated to comply with ASME Y14.5-2009.  It contains some color illustrations, including those of CAD models of assemblies.  This text also makes a tremendous reference resource. For self-study or classroom use.

[Text Contents]

#1 THE BASICS
• Where to begin a stack
• Designating positive and negative routes
• What are you calculating?
• What dimensions are factors
• How to push the parts to create the worst case
• Which geometric tolerances are and are not factors
• Finding the mean
• Calculating boundaries for GD&T, MMC, LMC and RFS Material Condition modifiers
• Mean boundaries with equal bilateral tolerances

#2 STACK-UP ANALYSIS OF AN ELEVEN PART ASSEMBLY USING PLUS AND MINUS TOLERANCING
• The calculations
• The loop analysis chart
• The numbers analysis chart
• Finding MIN and MAX gaps

#3 VERTICAL vs. HORIZONTAL LOOP ANALYSES FOR FEATURES OF SIZE
• Where to start and end
• Graphing the loop
• Minimum and maximum gap analysis

#4 ASSEMBLIES WITH PLUS AND MINUS TOLERANCES
• Multiple dimension loops
• Positive and negative values
• Airspace vs. interferences

#5 FLOATING FASTENER FIVE PART ASSEMBLY ANALYSIS
• Resultant conditions
• Virtual conditions
• Inner and outer boundaries
• Mean boundaries
• Converting to radii
• Mixing widths and diameters
• Complex loop analyses with geometric dimensioning and tolerancing

#6 FIXED FASTENER ASSEMBLIES
• Calculating overall minimum and maximum assembly dimensions
• Mixing slots, tabs, holes and shafts
• Calculating minimum and maximum gaps within the assembly
• Projected tolerance zones for total runout as a factor
• Determining if geometric tolerances are a factor
• Ruling out features and patterns as factors

 

#7 A RAIL ASSEMBLY
• Threaded features
• Multiple geometric controls
• Projected tolerance zones
• Gaps with and without perpendicularity as a factor
• Calculating interference
• Theoretically vs. physically worst case possibilities
• When logic becomes an integral step
• Factoring in assembly conditions
• Maximum wall thickness vs. minimum airspace for assemblies

•How to determine the right routes                                                                                                                                                               

• What can go wrong and how to correct it

#8 SINGLE-PART ANALYSIS
• Two-single segment positional controls
• Switching datum reference frames and accumulating geometric tolerances
• Datum features at MMC (pattern shift)
• Profile tolerances
• Flatness
• Envelopes of perfect form at MMC
• Creating envelopes of perfect orientation at MMC
• MIN and MAX axial separation
• Datum planes vs. datum features
• Separate requirements and accumulating tolerance
• Tolerances in degrees; Trigonometric function introduction
• Composite positional tolerancing

#9 FIVE PART ROTATING ASSEMBLY ANALYSIS
• Position
• Perpendicularity
• Parallelism
• Profile
• Flatness
• Threaded holes with projected tolerance zones
• Mounted screws
• Part to part analysis (from two parts to an infinite number of parts
• Runout
• Total runout
• Concentricity
• Positional coaxiality
• Simplifying a complex assembly
• Determining assembly housing requirements
• Radial clearance MIN and MAX calculations
• Interference calculations

#10 TRIGONOMETRY AND PROPORTIONS IN TOLERANCE STACK-UP ANALYSIS
• Rocking datum features
• Constructing a valid datum
• Consideration of differing orientations from measurement to assembly
• An in-depth assembly analysis using trigonometric functions
• Computer programs vs. a personal analysis
• Vertical stacking as it effects horizontal housing requirements
• When stacked parts are not flat or parallel
• Formulae to calculate worst case fit conditions when trigonometry is a factor
• Using proportions and trigonometry to calculate fit conditions beyond the GD&T formulae

#11 STATISTICAL TOLERANCING
• Gaussian Frequency Curve
• Standard Deviations
• Plus or Minus 3 Sigma
• Root Sum Square Formula
• Steps to Calculate and Apply Statistical Tolerances
• Statistical Tolerancing Applied to Plus and Minus Toleranced Assemblies
• Statistical Tolerancing Applied to Geometric Toleranced Assemblies
• When Best to Allow Statistical Tolerances and When it Should Not Be Allowed
• The Logic of Statistical Tolerancing
• Modifying the Root Sum Square Formula with a Safety/Correction Factor
• Reintegrating the Statistical Tolerance into the Assembly

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