Part and Assembly GDnT

[jpjamo]

Howdy,

I have been doing a bunch of reading on GD n T through James Meadows' text. It has been definitley a good buy as the more I read it the more I seem to understand on the matter (I think!).

However, I am working on a project were the client wants a quality drawing showing a plastic button assembled to a plastic molding.

My first problem is the button. The mounting points (which are flexible flange like things that are heat staked in the assy) on the button need to be controlled so I have a part drawing showing the button in side view defineing a datum A which is a flat surface on the button. I then have a front view with a Feature Control Frame that indicates a profile surface control on the mounting flanges of 0.2 while the datum A is held. These surfaces are non-planer so flatness or the like is not an option.

Is this a valid way to contol these mounting flanges?? They are the most important area I think because if they are out of whack when assembled the button is out of shape in its housing.

My second problem is the assembly. Is there a way I can control the orientation of the button in the assy with GDnT?
I would like to indicate again a profile surface control on the main button surface and/or a concentricity control between the button and its housing (in their nominally designed assy position) but I have not been able to find any examples of such.

Any feedback would be greatly appreciated!

Cheers
James

 

[Tunalover]

James-
I suggest you re-post with an attached sketch. A picture's worth a thousand words.


Tunalover

 

[jpjamo]

Hi Tunalover,

I have uploaded a picture at mooload ->

http://www.mooload.com/file.php?file=files/1134038227/gdnt+reference+part+2.jpg

What it shows is a button that is a much simpler representation of what I am talking about - I couldn't put the actual one up. One main difference is that on the actual button the ONLY flat surface is off the posts that are marked as datum A - everything else is curved in 2 directions.

One thing I thought about doing was giving a dimension to the points marked W, X, Y & Z - I could then give a positional tolerence frame for each point - saying it had to be within 0.2 whilst holding datum A??


Cheers
James