Profile of a Surface - Applying Profile of a Surface Geometric Control Symbols

[optomist1]

Good Day to All,

I know I have this written down in my notes....of course my course notes are not with me;

When does one use the "all around", the "between" or "no symbol" for applying Profile of A Surface geometric control?

Thank you for your assistance..

Regards,
Marty

 

[bobdoering]

"All Around" means to surfaces all around the part view shown (not limited to the surface the leader line arrow is pointing at).

"Between" means limited segment of aurface between designated extermities

No symbol means just the surface indicated by the leader line arrow.

 

[optomist1]

Hi Bob,

Thank you for the information....I am finding out just how powerful a Geometric Control "Profile" can be....

Regards,
Marty

 

[Jim Wynne]

Hi Bob,

Thank you for the information....I am finding out just how powerful a Geometric Control "Profile" can be....

Regards,
Marty

Unfortunately, it's used far too often by lazy designers who think they can control all kinds of things with it. It's especially abused by using it to control feature locations that should be controlled with position tolerances.

 

[optomist1]

Hi Jim,

That is exactly the point of the material I am covering now....."correct and efficient use of Profile....it is not meant as a catch all.....

Regards,
Marty

 

[bobdoering]

Look on the bright side, usually a bad GD&T callout is still better than a traditional tolerancing.

The other brutalized usage of GD&T is concentricity - which is for use in rotating cylinders (drive shafts, etc.), not for fit.

 

[optomist1]

Hi Bob,

Good point(s) in fact, one of my first post graduation jobs was Product Assurance on rotating mass gyros/guidance components...I was fortunate; for six months to be under the tutelage of a bonafide metrology sensei....where concentricity was correctly called out and saw how relatively expensive it was to verify....

Thanks for the insight....

Regards,
Marty