two days gd&t course for virtue technology sdn bhd.day1

Geometric Dimensioning & Tolerancing

(GD&T) 23-24th Aug 2017

For: Virtue Technology Sdn BhdAddress: PLOT 202, Lorong Per. Bukit Minyak 11, Kaw Per. Bkt Minyak, 14100 Bukit Tengah, Penang

Presented by: Timothy WooiFor: JMC Group of Companies

Geometric Dimensioning & Tolerancing (GD&T)

Course Content. Day 1, Morning

Introduction to GD&T

• What is GD&T, GD&T Definition &

Application of GD&T

Definition of GD&T

• What is Dimensioning & Tolerances.

• Exercise : Simple definition on

Geometry, Dimensioning and

Tolerance.

• Dimension

Standards for GD&T.

• ASME , ISO & Din Standards

Direct Tolerancing

Methodology

Application examples on sizes

and dimension with lecture with

some simple illustration

Exercises

• Sample Lead frame example.

• Application using lead frame

sample


Course Content. Day 1, Noon

Common Symbols in GD&T.

• List of symbols and their interpretation

Assessment

Geometric Characteristic Symbols

• Symbols application

• Datum reference application to various

symbols

• Assessment Exercise

• Composite Tolerancing

• Example and exercise


Rules for Drawing and DesignsEnvelope Principle.

Rules for Gear and Splines.

Regardless of feature size.(RFS) settings

Maximum Material Condition (MMC)

Least Material Condition (LMC).

Virtual Condition and Resultant Condition.

Case studies:Interpretation of drawing and designs

involved hardware components

ExerciseStudy of tolerancing condition

Maximum Material Condition (MMC),

Least Material Condition (LMC) and

Regardless of Feature Size (RFS)

application and interpretation

Day-2, MorningSimultaneous Requirements for Combined parts Profile Controls

Profile tolerancing- Computation of holes in relation to leading hole in various materials condition.

Composite Position Tolerance

- Application of the condition to achieve better machine settings.

Exercise

Computation and interpretation


Two Single Segment Feature Control Frame- Interpretation and understanding- Exercises and examples - Assessment test: -Using GD&T on various component, interpret fabrication of parts successfully considering business factors.

Day-2, Noon


Inspection for proper Tolerances & Dimensioning- Appropriate and correct approach of during inspection. - Correct position and method of measurement of parts based on the technical drawings. - Datum & relevant Selection - Definition of datum reference frame –

Definition of datum reference points -Decision Diagrams Study of Sample Drawings -Exercise and Workshop: Interpretation of sample mechanical drawings. -Convert from +/- to true position tolerancingConclusion and Q & A session

End of day 2

GD&T Course Objective

(Based on ASME Y14.5M-1994)


To allow Participants to master techniques of GD&T in the ASME standard to;

integrate smoothly into engineering design applications and modern inspection systems at work.

Provide Participants with Fundamental concepts of GD&T to express, understand and interpret drawing requirements using GD&T to ANSI / ASME Y14.5M Standards.

GD&T: An International Language

GD&T: An Exact Language

GD&T Provides Uniformity

What is GD&T?


GD&T stands for Geometric Dimensioning and Tolerancing, as defined by ASME Y14.5


GD&T: An International Language

GD&T is an international system of symbolic language used on drawings to accurately describe a part.

Definition

GD&T: An Exact Language

Geometric tolerancing is an exact language that enables designers to “say what they mean” on a drawing, thus improving product designs.

Production uses the

language to interpret

the design intent, and

inspection looks to the

language to determine

set up.


GD&T is a method for stating and interpreting mechanical engineering design requirements.

GD&T is a very useful & efficient tool to make engineering drawings a better means of communication from design through manufacturing and inspection.


GD&T Provides UniformityBy providing uniformity in drawing specifications and interpretation, GD&T reduces;

controversy,

guesswork, and

assumptions

throughout the

manufacturing and inspection process.


Language of GD&T

The language consists of a well-defined set of symbols, rules, definitions, and conventions that can be used to describe the;

size, form, orientation, and location tolerances of part features.


Application & Advantages of GD&T

The advantages of applying GD&T in design specifications are:

Uniformity in design practiceClear interpretation of tolerance classification. Ensure interchangeability Maximum tolerance allocation.


In-depth knowledge of GD&T application allows optimum form, fit & function between the various complex pieces of parts assembly.

Starting with basic principles in coordinate dimensioning & tolerancing and progressing on these principles to understand & apply GD&T requirements to ad concepts to real work applications.


Before an object can be built, complete information about both the size and shape of the object must be available.

Definition of GD&T

The exact shape of an object is communicated through orthographic drawings, which are developed following standard drawing practices.

Definition of GD&T

The process of adding size information to a drawing is known as dimensioning the drawing.

Definition of GD&T

Geometrics is the science of specifying and tolerancingthe shapes and locations of features on objects.

Once the shape of a part is defined with an orthographic drawings, the size information is added also in the form of dimensions.

Definition of GD&T

Dimensioning a drawing also identifies the tolerance (or accuracy) required for each dimension.

GdnT Rules Based System

Dimension


Basic Dimension.ppt

Basic Dimension.ppt

Dimensioning standards play a critical role in the creation and interpretation of engineering drawings. They provide a uniform set of symbols, definitions, rules, and conventions for dimensioning.

Standards for GD & T. – ASME, - ISO, - Din

Without standards, drawings would not be able to consistently communicate the design intent globally.

ANSI - American National Standards Institute

- This institute creates the engineering standards for

North America.

ISO - International Organization for Standardization

- This is a world wide organization that creates engineering standards

with approximately 100 participating countries.

DIN - Deutsches Institut für Normung

- The German Standards Institute created many standards used

world wide such as the standards for camera film.

JIS - Japanese Industrial Standard

- Created after WWII for Japanese standards.

CEN - European Standards Organization


These two standards have emerged as the primary dimensioning standards. There are also several other standards that are in use in lesser degree eg. Deutsche Industrie Norm (DIN) standard.

There is increasing pressure to migrate toward a common international standard as the world evolves toward a global marketplace.

Most dimensioning standards used in industry are based on either the American Society of Mechanical Engineers (ASME) or International Organization for Standardization (ISO) standards.

ASME is an engineering society focused on mechanical engineering in North America, is thus a standards organization, a research and development organization, a provider of training and education, and a nonprofit organization. - A document that communicates a precise description of a part.- This description consists of pictures, words, numbers, and symbols.

Standards for GD&T. (ASME),American Society of Mechanical Engineers.

http://en.wikipedia.org/wiki/Mechanical_engineering

http://en.wikipedia.org/wiki/North_America

http://en.wikipedia.org/wiki/Standards_organization

http://en.wikipedia.org/wiki/Research_and_development

http://en.wikipedia.org/wiki/Nonprofit_organization

This standard was created to unify design and interpretation, minimizing errors in the production of parts and assemblies.

In 1982, the first GD&T (Geometric Dimensioning and Tolerancing) standards were introduced to the ASME.


The standard was revised in 1994 and again in 2009.


ASME StandardsASME Y14.5 – Dimensioning and TolerancingASME Y14.5M-1994 Dimensioning and TolerancingASME Y14.5.1M-1994 Mathematical Definition of Dimensioning and Tolerancing Principles

Many multi-national corporations use ASME Y14.5 (ASME Y14.5M-1994 or ASME Y14.5-2009) as their GD&T standard worldwide for their international operations.

The ASME Y14.5 standard is considered the authoritative guideline for the design language of GD&T.

ASME Y14.5-2009 is a replacement of ASME Y14.5M-1994.

Now, a consensus committee of experts has revised ASME Y14.5 for 21st-century applications.

Important changes address: concept of feature of size; datum references and degrees of

freedom; composite position tolerances; surface boundaries and axis

methods of interpretation; profile tolerances; and symbology and modifiers tools.

Additionally, the subject matter has been restructured for better readability, with profile, orientation, and form now in separate sections, and material within sections reorganized.)


ASME RevisionsASME Y14.5

Dimensioning and Tolerancing

ASME Y14.5M-1994 Dimensioning and

Tolerancing

ISO 1101:2004 Geometrical Tolerancing.


The International Organization for Standardization (ISO) also has a version of GD&T, which they call ISO 1101 Geometrical Dimensioning and Tolerancing (GD&T).

At present the ISO standards do not recognize the interpretation of concentricity and symmetryas defined in the ASME Y14.5 standard.

The concentricity and symmetry characteristics in ISO have the same interpretations as the position characteristic in the ASME Y14.5M 1994 standard.

Differences between the ASME and ISO for GD&T

Nomenclature differences

Other Differences:1. In ASME the rule #1 controls Size and Form simultaneously.

In ISO, Form is independent of Size and is additive to size. An encircled E symbol in ISO invokes the envelope principle in ISO.

ASME ISOBasic Dimension Theoretically Exact DimensionFeature Control Frame Tolerance FrameReference Dimension Auxiliary DimensionTrue Position Theoretically Exact Position

Other Differences:2. General Tolerances are not covered under ASME. General tolerances can beapplied in ISO drawings by putting a note ISO-2768. When ISO-2768 is referred on the drawing, general tolerances are invoked on linear and angular dimensions.3. ASME does not specially define non-rigid parts as separate entities. A F-modifier is used to show that the geometry should be checked under Free State. ISO shows non-rigid parts by putting a note stating ISO-10579-NR in the title block.4. Under ASME, tolerance zones are always Normal to the geometry. Under ISO,you can define tolerance zones that are at another angle to the geometry.5. ASME defaults to third-angle projection. ISO defaults to first-angle projection


Other Differences:6. Under ASME datum feature leader cannot point towards axes and Center planes. Under ISO the datum feature leader can point to an axis or a Center plane.7. Under ASME, datum precedence has to be strictly maintained. Under ISO, ambiguous order of datums is allowed, so long as the order is not important.8. Under ASME, composite position tolerances are interpreted as PLTZF and FRTZF. Under ISO, the two segments of a composite position tolerance frame are interpreted as separate tolerances.9. Under ASME, Concentricity and Symmetry are always applied RFS. Under ISO they can be applied at MMC, LMC or RFS.10. ASME is a single standard. ISO has collection of standards addressing various Geometric tolerances.


Application examples on sizes and dimensions. Dimensioning and tolerancing philosophy -

Fundamental Rules.

Direct Tolerancing Methodology

There are some Fundamental Rules that need to be applied.These can be found on the GD&T Rule Based System.

Fundamental Rules

Exercises

Fundamental Rules (trainer's copy).ppt

Fundamental Rules (trainer's copy).ppt

Course Content. Day 1, Noon


• List of symbols and their interpretation

Assessment


• Symbols application

• Datum reference application to various

symbols





Rules for Drawing and DesignsEnvelope Principle.

Rules for Gear and Splines.

Regardless of feature size.(RFS) settings

Maximum Material Condition (MMC)

Least Material Condition (LMC).

Virtual Condition and Resultant Condition.

Case studies:Interpretation of drawing and designs

involved hardware components

ExerciseStudy of tolerancing condition






List of symbols and their interpretation Assessment

Common Symbols in GD&T

Exercise

Study of tolerancing condition





GD&T Symbols

GD&T_Symbols_Reference_Guide.pdf

GD&T_Symbols_Reference_Guide.pdf


Symbols application

• Datum reference application to various symbols





Exercise

Workshop Examples (trainer's copy).ppt


Rules for Drawing and Designs

Envelope Principle.

• Rules for Gear and Splines.

• Regardless of feature size.(RFS) settings

• Maximum Material Condition (MMC)

• Least Material Condition (LMC).

• Virtual Condition and Resultant Condition.


Rules

Rules 1&Rule 2 (trainer's copy).ppt


Case studies:

Interpretation of drawing and designs involved hardware components


Workshop Examples




Exercise

Study of tolerancing condition


Least Material Condition (LMC) and Regardless of Feature

Size (RFS) application and interpretation

Exercise



Day-Two, MorningSimultaneous Requirements for Combined parts Profile Controls

Profile tolerancing- Computation of holes in relation to leading hole in various materials condition.

Composite Position Tolerance

- Application of the condition to achieve better machine settings.

Exercise

Computation and interpretation


Two Single Segment Feature Control Frame- Interpretation and understanding- Exercises and examples - Assessment test: -Using GD&T on various component, interpret fabrication of parts successfully considerating business factors.

Day-Two Noon


Inspection for proper Tolerances & Dimensioning- Appropriate and correct approach of during

inspection. -Correct position and method of measurement of parts based on the technical drawings. -Datum & relevant Selection -- Definition of datum reference frame –

Definition of datum reference points -Decision Diagrams Study of Sample Drawings -Exercise and Workshop: Interpretation of sample mechanical drawings. -Convert from +/- to true position tolerancingConclusion and Q & A session End of day 2

Thank You!

End of Day 1


two days gd&t course for virtue technology sdn bhd.day1

Engineering