I’m familiar with geometric dimensioning and tolerancing (GD&T) being used extensively in the aerospace and automotive industries, however many industries don’t use it at all. Is there a need for GD&T in Wind and Solar energy, computers and electronics, or medical devices?


I believe my question is: “How useful is GD&T?” If you use it, why? What does your product or company gain by using GD&T? If you don’t use it then please feel free to comment on why your company does not use GD&T?


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I use GD&T all the time. Most of the equipment I design is made in China. If you don't add a large helping of GD&T you will not get the quality you require. I find manufactures in China suffers from "it's good enough" syndrome. One issue that comes to mind is a weldment I sent over. Even though I did not need a accurate location, the welded part should be square. It did not end up that way. India can be worse. We shipped a frame from India that was bent about two inches in the center. Problem was, "no where on the print did it say it had to be straight". Here in the U.S. manufactures tend to take some pride in a finished weldment. Everything is located accurately and all angles are square and straight, and the part just looks good upon arrival.
It's the simplest, somewhat universal language for conveying on a drawing what you really need the part to look like to function properly. When there is a difference in language between designers and manufacturers, then having a symbolic language that is concise and well defined is essential. Even when these groups use the same language, the discipline of GD&T ensures that the design is faithfully executed when hardware is produced.
If done correctly, it will also allow the greatest manufacturing tolerance (lowest cost) that will still let the part assemble and function properly.
It also assists when analyzing assembly tolerance stackups to guarantee that the asembly will go together everytime. I work with 30-year old legacy drawings that had no GD&T (or worse yet, incorrectly applied GD&T) and it is amazing that we didn't have more assembly interferences than we did (sometimes having a production run measured in a few dozens is a blessing compared to the embarrassment that would have ensued if we were making things by the thousands).
There was a time when Draftsmen reported to Engineers and GD&T was crucial for communicating the idea across a spectrum of individuals using the part drawing. Unfortunately, with the advent of CAD, the Darftsman became obsolete, allowing engineers to develop parts without help. This has resulted in low quality drawings as a whole.
I'm trained as a draftsman, and educated as an engineer, somewhat. The drawings I see from the desks of my peers would make my old instructors weep.
What took me two years of post secondary training learning, engineers are given a 16 week course to learn absorb and use. Believe me, they don't.
GD&T is absolutely essential when communicating ideas in a drawing. There can be no shortcut taken in order to accomplish the goals of a given part. GD&T is nothing less than a great insurance policy against shoddy fabrication, expensive rework, and costly delays. What could be made here in the States/Canada without it, can't be produced in emerging industrialized nations. As Ward pointed out; overseas manufacturers suffer from a severe lack of training and education; they have some kid operating a turret lathe that was picking rocks yesterday and he can't tell a 6 from a 5.
Best to use it,

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