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Level 1:  Principles and Applications of

Geometric Dimensioning and Tolerancing

(per ASME Y14.5M-1994)

     COURSE DESCRIPTION: This course uses the strategy of giving the participants a thorough knowledge of Geometric Dimensioning and Tolerancing by detailing critical information on the basics of GD&T, then providing lectures, realistic examples, discussions and applications problems on the more difficult principles of GD&T.  It allows the participant the opportunity to learn and apply techniques in datum selection and tolerancing optimization. This approach will preserve functional product requirements, while taking into consideration manufacturing difficulties, introducing more producible tolerances, practical datum structures and pre-planning measurement methods.  All dimensioning techniques discussed are functional, but also producible and inspectable.  It shows how bonus tolerances, composite tolerances and proper datum selection can decrease costs while preserving functionality.  The lectures, discussions and applications problems presented not only give participants a thorough knowledge of the meaning of each geometric characteristic symbol, but also a perspective on how each symbol relates to the others for strengths and weaknesses, capabilities, advantages and disadvantages.   

Throughout this course the participants are constantly reminded of the most common errors, pitfalls and traps that any user can easily fall victim to and also how to avoid such problems.  Doís and Don'ts of proper tolerancing are reinforced in every segment of the course by showing how they apply to realistic assembly tolerancing conditions.  It shows the best usage of all geometric characteristic symbols and datum structures.  Inspection methods and quality assurance strategies are stressed to create an understanding of the theory of geometric tolerancing by creating a physical embodiment of that theory through proper inspection techniques, gage and fixture design and usage.  A thorough discussion of the basics of GD&T principles is the basis for the first part of the course.  Then the course escalates into more advanced techniques and principles that build on the participantsí gained knowledge in every segment of the course to that point.  The goal of this course is not only to give the participants a comprehensive knowledge of Geometric Dimensioning and Tolerancing techniques, but through the use of discussion and applications problems, the ability to apply these techniques to their product lines with a great deal of confidence.

COURSE MATERIALS:  Geometric Dimensioning and Tolerancing in 2007

   CLASS SIZE:  We only require that the classroom be of sufficient size to accommodate the number of course participants comfortably. 

   WHO SHOULD ATTEND:  This is the course that provides the foundation of GD&T knowledge upon which all advanced courses rely.  Anyone involved with improving the quality of their parts should attend.  This course is designed for personnel whose work requires them to either communicate, interpret or manufacture products through the use of engineering drawings and/or CAD models.  

  COURSE DURATION:  Recommend four 8-hour days; also available in a 3-day format.


1)      Overview of GD&T Basic Principles.  A sheet of notes is given on 1. Rules, 2. Datum Selection Criteria, 3. Fixed and Floating Fastener Formulas and 4. Doís and Doníts for Geometric Characteristic Symbols.  A lecture and discussions on the major principles of geometric dimensioning and tolerancing will be given by presenting a simple assembly of mating parts and applying geometric controls to each part in the assembly. The effects of MMC, LMC and RFS concepts are discussed.  Inner and Outer Boundaries, Virtual Condition and Resultant Condition of features of size are explained.  Gage design for position controls will be introduced in this section.

a.       Lecture, examples and discussion


2)      Geometric Characteristics and Their Inspection. All fourteen geometric characteristic symbols will be explained in a food chain of symbology to show how each symbol relates to the others for control of size, form, orientation, profile, runout and location.  Geometric Characteristic symbols covered include; flatness, straightness, circularity, cylindricity, perpendicularity, angularity, parallelism, profile of a line, profile of a surface, circular runout, total runout, concentricity, symmetry and position. This will give each participant a perspective of how to choose exactly the right characteristic for every step of the part definition.  Inspection of all characteristics will be discussed and several options shown for each.

a.       Lecture, examples and discussion


3)      Datum selection, choosing the perfect geometric characteristic for parts and assemblies. Fixed fastener assembly mating part tolerance formulas and the effects of modifiers (MMC after datum features) are also emphasized.  A more complex assembly will be used to explain the proper selection of datum features and a linear progression of geometric controls.  The fixed fastener formulas will be thoroughly explained and used to calculate and distribute geometric tolerances for maximum manufacturability and functionality.  Process capability, producibility and functional product requirements are considered and shown to work in tandem to create the best tolerancing scheme possible. Threaded holes, positional tolerancing, projected tolerance zones and inspection techniques are discussed.

a.      Lecture, examples, discussion and applications


4)      Producibility and Measurement Considerations.  How manufacturing processing can influence datum selection without adversely affecting part functionality.  How to correctly distribute tolerances in an assembly to reduce difficulties in part manufacture. How to imply a manufacturing and a measurement plan in sequencing geometric controls.

a.      Lecture, examples and discussion


5)      Holding Direct vs. Indirect Functional Relationships in an Assembly.  A floating fastener assembly will be used to explain how important functional relationships can be held using different datum structures.  How to increase tolerances by proper datum selection is discussed.

a.      Lecture, examples, discussion and application problems


6)      Application of Common Tolerancing Methods and Datum Structures.  A series of application problems are used to build participants' knowledge and confidence in applying common datum approaches and tolerancing methods.  Circular surfaces, planar surfaces, free form surfaces, datum targets, free state variation, the BOUNDARY concept for elongated holes and other oddly configured features.

a.      Examples and Discussion


7)      Commonalities in Tolerancing Approaches on Dissimilar Part Geometries.

a.       Profile of a Surface all-around, Two Single Segment Position, Perpendicularity of Centerplanes, Simultaneous Gaging vs. Separate Gaging Requirements, Analyzing Geometric Tolerances, Angular Orientation Datums, Analyzing Tolerances for Minimum and Maximum Axial Separation, Wall Thickness and Housing Requirements.


8)      Design, Dimensioning and Tolerancing of Functional Gages and Fixtures.  Quality Assurance Strategies and Measurement Planning.

      a.  Lecture, example and application problem


9)      Converting from Plus and Minus Tolerancing to Positional Tolerance

a.      Calculating Geometric Tolerances for Functionality and Cost Savings 

b.      Lecture, examples and application problems


10)  Composite Position vs. Two Single Segment Positional Tolerancing.

a.      Lecture, examples and discussion


11)  Composite Profile vs. Two Single Segment Profile Tolerancing.

a.      Lecture, examples, discussion and application problem


12)  Applying Position Tolerances to a Complex Assembly with Multiple Datum Structures for Floating and Fixed Fastener Assembly Conditions

a.      Lecture, examples, discussion and application problems

 This course is recommended to run for 4 consecutive days, 8 hours a day.  A 3-day version of this course is also available.  One hour will be taken for lunch each day.  Breaks will be taken at regular intervals. 

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