Friday, June 12, 2009

GD&T Concepts Definition | GD&T symbols explanation with pictures | Chart with Examples

What is Gd&T and How to apply:

Geometric Dimensioning and Tolerance is always heart of Engineering Drawing. Though draughts men are using it since engineering drawing is evolved, not all engineers are good at it.

Interestingly use of CAD software's and growing no of Design Engineers has brought awareness about it.

Engineers would expect the product from machine shop as they have defined in the drawing. Its not fair to expect all dimensions of component to be as per drawings eg: Len 25.05

Every machines in the shop floor has its own tolerance adding to it human errors are always possible. Even though advance technologies and use of robots in CNC machines can reduce errors. Still specifying tolerance is very essential for critical dimensions.

This has made Engineers to specify Tolerance for geometry,Feature Dimensioning,Feature position. On the other hand, it is very important that shop floor worker understand drawings as Design Engineer intended. After machining process, machined component has to be checked for specified tolerances by Quality circle people. Overall knowledge about GD&T is every important in an industry.

ASME Y14.5, GD&T concepts

Fig: GD&T symbol and how it works.

Now I will show you site, Draftingzone which is dedicated for Drafting engineers. They give training,sell books on Geometric dimensioning and tolerancing. They have panel of experts who could train engineers on line or on field by paying.

 GD&T Basics and Symbols

Fig: Tolerance zone and its use.

The above you can see the GD&T symbols explained with pictures, how to use it, where to apply tolerance. This poster available at drafting zone and you can buy now..

Disclaimer: This GD&T book/Poster is availabe at Draftingzone for purchase,All materials contained on the site are protected by United States copyright law and may not be reproduced, distributed, transmitted, displayed, published or broadcast without the prior written permission of Genium Group, Inc.