Geometric Dimensioning and Tolerance (GD&T) is a vision and design tool that helps engineers and designers. It communicates and brings part designs to life, how to move from paper and screen to something functional, tangible, and physical.  If properly documented with GD&T, you can build a part that matches the plan on paper in terms of fit and function.

Excedify’s G&T courses are prepared by a team of experienced GD&T trainers, currently working with engineering professionals, and technicians from giant companies, especially with managers of German origins. Since we are aware that every specialist working in this area needs perfect quality education.

 

GD&T basics

The manufactured object will be a different size than the original CAD model due to changes in the manufacturing process.  In order to have better control and management of variations, engineers and manufacturers use a symbolic glove called GD&T.  It stands for Geometric Dimensions and Tolerance.

Before GD&T, production characteristics were defined by the X-Y area. For example, when drilling an assembly hole, it must be at a specific X-Y point.

For functional assemblies, products with many parts, or components with complex functions, it is important that all parts work well together. All relevant parameters and factors must be specified to minimize the impact on the production process and associated investments. Although it is still functional.

Doubling clamping tolerance can lead to higher rates of scrap and tool changes, doubling or even increasing the cost. GD&T is a system that optimizes its functionality without increasing production costs.

GD&T is a system that describes the intent of the design rather than the resulting geometry. Like vectors and mathematical expressions, this is not the real object, but a representation of it.

It is easier to describe the shape of a product in terms of its function and production approach than to describe it all in terms of linear dimensions.  It provides tools to communicate with manufacturers, customers, and quality control inspectors.

Done correctly, GD&T also allows you to control process statistics (SPC), which reduces product rejection rates, and assembly errors.

As well as the effort required to control quality, it helps save a significant amount of money and critical resources. This is because we share the same ideas and language about what we want to achieve.

 

The function of GD&T

The drawing must indicate the dimensions of all the elements of the part. In addition to these dimensions, tolerances with minimum and maximum tolerance limits must be specified.

There are parts with very unpredictable variations and too complex geometries, so they require GD&T techniques that go beyond simple additive/subtractive tolerances. Similarly, a cylinder with a tolerance diameter will not precisely fit into its hole if it is bent during its manufacture.

That is why righteousness must also be controlled. This would be difficult to communicate with more or less conventional tolerances. However, pipes that must be perfectly adapted to the complex surfaces to which they are welded need to have their surface profiles controlled.

The art of tolerance requires determining the correct variation in design elements to maximize the success of the product manufacturing process and the visual and functional purpose of the part. The metric system has international standard tolerance (IT) grades that can be used to indicate tolerances using symbols.

Drawings should accurately convey the idea of the product without adding complexity or unnecessary limitations. It may be helpful to remember the following suggestions:

• The clarity of a drawing is even more important than its accuracy or completeness.
• Improve readability, draw dimensions and tolerances above the boundaries of parts, and apply them to lines that appear in perfect outlines.
• Use one-way read directions, transfer part features, group and/or place overlapping dimensions, and take advantage of spacing. Always design your designs with as many tolerances as possible to keep costs down.
• Use the general tolerances listed at the bottom of the drawing for all dimensions of the part. A wider or narrower specific tolerance shown in the drawing replaces the overall tolerance.

 

Excedify GD&T Course Curriculum

Excellent gd&T training for fabricators, inspectors, technicians, engineers, and designers is paramount to the maximum scope of your career.  This specific online course covers the basics of intermediate concepts.  At the end of the entire course, you will have a lot of knowledge and will be able to safely understand and realize the engineering drawings of gd&t.

The course is intended for beginners and intermediate levels.  The instruction is done from the hill, going from the basics to the intermediates, doing deep moderately.   It does not matter if you already have the knowledge, it is recommended in the same way, since it will help you extend the information you know.

To take the course you don’t need much, just have basic technical drawing reading skills, including the ability to interpret drawings and projections and know something about dimensional tolerances.

This training is given through various videos, which contain animations and graphics, with specialized content in the illustration of concepts. As the course progresses, different exams are carried out to check the level of knowledge acquired.

At the end of the chapters, the students must apply the knowledge in projects, and practical tasks, in order to maintain learning, since practice makes the teacher.

The direction of this course not only includes the symbols but also, seeks to teach you the meanings behind each of them. As well as, tolerance zones, measurement methods and how to use gd&t safely, among others. In order to save costs when designing and manufacturing different parts.

It is quite attractive, since, it makes dynamic lessons with real and everyday examples, makes you study the cases, and provides practical exercises.  It offers support team that will guide you through the entire process, is available to your needs.  And best of all, they give you your certificate at the end of the course.