Need Examples Of GDT

[RPF1968]

Hi

I am a trainee CAD Draughtsman and need help with applying GDT.
My job consists of creating detail drawings from 3D parametric models created by our engineers in Seimens NX.
(The dimensions on the models are applied to the mean value.)

The models vary in how much that they adhere to design intent.

I need to have more of an understanding of GDT.

All that I have read about GDT just show how to use it in respect to a single part which I can understand - the difficultly that I have is in applying it within the context of an assembly.

Does anyone know of any books or literature which might tell how to apply it with 'real world' examples rather than just explaining - positional, cylindricity .etc.

Thanks

Richard

[Kelly_Bramble]

Draftsman = Draughtsman
USA vs UK

I think it is great that you’re looking beyond part level dimensioning and tolerancing but being that you are a “trainee CAD Draughtsman” I think you’re getting ahead of yourself in regards to what you should be learning.

First, you should be mastering CAD and part level drafting. Also, engineering process, change notice creation, team work skills and learning about the products you’re working on. I sincerely hope you have a mentor or a guru to help you out.

Then you should learn engineering material characteristics, corrosion (galvanics), part level manufacturing process, and manufacturing process tolerance capabilites.

From there you should learn about end-item assembly or integration requirements, applicable specifications, and assembly level drafting.
The short of it – learn the basics first before moving on to more advanced applications, like tolerance analysis and assembly tolerance distribution methods.

There are books available that do illustrate assembly level tolerance structures, however I doubt you are going to find a book with YOUR application centric examples. This is why learning the basics is so one important in that when mastered you can then develop the unique part and assembly level design, tolerance structures in view of application and manufacturability.

[Kelly_Bramble]

Just for reference, I have created several and more to come GD and T application videos as follows:

• GD&T Application Single Datum Axis - Two Datum Features
• Position Tolerance Application GD&T
• GD&T Training Video Refinement of Orientation Using Parallelism
• GD&T Circularity Flare Fitting Application
• What is the Right Flatness Tolerance for a Gasket Application GDT Training

GD&T Geometric Dimensioning and Tolerancing Applications