GD&T Curriculum for our Inspectors and CAD Technicians

[NWrubberQA]

I need a good GD&T curriculum for our inspectors and CAD Tech. Any suggestions??

 

[Stijloor]

Re: GD & T Curriculum

I need a good GD&T curriculum for our inspectors and CAD Tech. Any suggestions??

I can help you. See my personal profile for specifics.

Stijloor.

 

[David DeLong]

Re: GD & T Curriculum

I don't know how to address this question since I have been training in GD&T for over 20 years and ASME certified. As Stiljoor stated "check my profile". I guess that is the answer then.

 

[Stijloor]

Friends,

There is such a great need for GD&T training. Engineering students graduate with virtually no clue about this very powerful engineering drawing language. I am always amazed when I ask my course Participants about previous GD&T education. Blank stares....:mg: Well, I do not mind and my friend David DeLong would agree that it keeps us busy. Well...right now is a little different.

I am curious what my Fellow Covers think. What needs to be done to promote the use of GD&T in the USA? Suggestions?

Stijloor.

 

[Jim Wynne]

Friends,

There is such a great need for GD&T training. Engineering students graduate with virtually no clue about this very powerful engineering drawing language. I am always amazed when I ask my course Participants about previous GD&T education. Blank stares....:mg: Well, I do not mind and my friend David DeLong would agree that it keeps us busy. Well...right now is a little different.

I am curious what my Fellow Covers think. What needs to be done to promote the use of GD&T in the USA? Suggestions?

Stijloor.

Part of the problem is that it's not something that can be learned in the abstract--you need to be able to actually see how the requirements apply to products. I do find it ironic that in general, quality people understand it much better than design people do, and the fact that design people use it without understanding it causes incalculable waste.

 

[Stijloor]

Part of the problem is that it's not something that can be learned in the abstract--you need to be able to actually see how the requirements apply to products. I do find it ironic that in general, quality people understand it much better than design people do, and the fact that design people use it without understanding it causes incalculable waste.

Jim,

So interesting you brought this up. When I was a machinist apprentice in The Netherlands, GD&T was part of the curriculum along with drafting, sketching, reading blueprints and the like. To us, it was another technical ABC you had to learn and master. When I moved to the US, I was very surprised about the lack of GD&T knowledge in design, manufacturing and in quality.

Stijloor.

 

[Matt Swartwood]

A few of us where I work luckily had experience through automotive, defense, and aerospace backgrounds. When it came to training the workforce, we had a very difficult time finding someone knowledgable who could do the training.

 

[David DeLong]

I agree with Jim that I have found that the people in Quality seem to have more knowledge in GD&T than the Designers. That said, it really isn't taught too well in colleges/universities in Canada but it should be an integral part of any mechanical technology. It just isn't.

It is a tough subject and if it wasn't for the fact that in my early vocational years, I was a CMM Operator at GM, I could not train in this subject. I know and understand metrology and, frankly, enjoyed it. It still took me about 10 years of GD&T training to become comfortable in fielding the various questions and when I first tried to GD&T Professional exam, I failed (have past it since though). It is not an easy subject.

The ASME Y14.5 standard does not state GD&T application so we have some training companies professing that we must place it everywhere on the drawing including having it as a default tolerance. We have all seen drawings loaded with GD&T and when we ask about its application, the answers were vague. We could end up with checking fixtures on features that have no meaning to its function and that has happened. How many times have we scanned a surface shown as a Profile when, in fact, it had no function and was in space?

If one does not need GD&T, it should not be placed on the drawing! Apply GD&T when a feature has a function or relationship to other features or the mating part.

There is a new ASME Y14.5 - 2009 out now. If you think the 94 standard was somewhat confusing, just go through the 2009 standard on datum reference frames. Wow - it seems to get more complex.

 

[Jim Wynne]

If one does not need GD&T, it should not be placed on the drawing! Apply GD&T when a feature has a function or relationship to other features or the mating part.

Great advice! Another evidence of ignorant designers is having drawings for mating parts where the GD&T doesn't match.

 

[Paul F. Jackson]

Dave,

If one does not need GD&T, it should not be placed on the drawing! Apply GD&T when a feature has a function or relationship to other features or the mating part.

If by GD&T you mean just geometric contols that use designated datum features (as necessary), specified basic geometry, and controls designated in feature control frames... not excluding other direct tolerancing methods necessary to completely define the end product...

then your advice is consistent with the fundamental rules described in 1.4(c).

Apply GD&T when a feature has a function or relationship to other features or the mating part.

If you mean that features need not be toleranced unless they have "a function or relationship to other features or the mating part"...

then your advice is contrary to the standard.

GD&T encompasses the complete dimensional definition process not just those designated by defined symbols. I trust that you do not disagree with 1.4(c) that "No more dimensions than those required for complete definition shall be given".

Paul