Most engineers and product designers have encountered geometric dimensioning and tolerancing, better known as “GD&T,” at some point in their careers. Some use GD&T quite often, whereas others rarely use it at all.

This system for defining and communicating design intent and part function can be intimidating for those who don’t know it well. In fact, many engineers aren’t even taught GD&T in school. 

Not every part requires the technical expertise of GD&T, but when it comes to complex CNC machining, GD&T is an excellent system to use. Here’s a closer look at 5 benefits of using GD&T:

Why Use GD&T in Complex CNC Machining?

  • Simple communication. GD&T allows you to convey substantial information about your part’s design using a relatively small amount of letters, numbers, and symbols. No long paragraphs of explanation necessary! The ability to communicate efficiently reduces back and forth between you and the contract manufacturing service you are working with.
  • Accurate production. Since GD&T is such a precisely articulated system of language, it minimizes ambiguity in the description of a part’s design. As a result, you can be confident that your part will be manufactured with the highest degree of accuracy and work as intended in the field.
  • Known tolerances. GD&T gives manufacturers a clear understanding of the tolerances for a specific part. It provides the maximum amount of tolerance for the part to function properly, which reduces part complexity so that you aren’t overspending for a minimum tolerance that you may not need. 
  • Universal language. You may find yourself in a situation where you want to work with a contract machining company in another country with a spoken language that is different from yours. Great news! GD&T is a universal language widely accepted across the world, thereby eliminating frustrating language barriers for overseas production. 
  • Precise assemblies. If you have two mating parts that need to come together in an assembly, GD&T is an excellent way to communicate how this interfacing can best take place. In these situations, GD&T clearly depicts the tolerances of each part so that manufacturers can easily tell if a measurement is off and adjust accordingly. 

It is best to decide ahead of time if you’re going to use GD&T to communicate with your contract machining provider. You want to avoid using both GD&T and traditional dimensioning language within the same design because it could cause confusion and lead to errors in manufacturing.

GD&T

If you don’t know GD&T already and would like to learn more, here are some helpful resources: 

At Reata Engineering we are experts in using GD&T to machine complex parts for our customers and will always be honest with you if we don’t think it’s necessary. Feel free to reach out to us and we can help you determine if your part design would be best served by GD&T.

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