Tricky Datum Reference Frame 2

[SSergey]

Hi Team,

Would you mind taking a look at the attached drawing and let me know if I am missing anything, please?

Thank you!

Best,
S

 

[SeasonLee]

1. Diameter symbol Ø need to be deleted at Datum C FCF callout, the toleranced zone is a derived median plane Instead of a cylinder
2. The feature of 2X Ø.197 is not a FOS(feature of size), a semi-circle is not a FOS, so only profile FCF can be used here, not position callout.
3. The DRF |A|B(M)|C(M)| is Okay.---(Edit by adding #3)

Season

 

[SSergey]

Season,

Thank you for the great comments!

 

[powerhound]

the toleranced zone is a derived median plane Instead of a cylinder

The datum is a centerplane, not a derived median plane. The centerplane is what needs to be in the tolerance zone, not the derived median plane.

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech

 

[SeasonLee]

Thanks for correcting on the right term used.

Season

 

[AndrewTT]

Does the stock material have a standard governing its form? If not you may be underdefined for the form of datum feature A.

 

[SeasonLee]

Its really a good practice to add a form control on datum feature A as recommended by AndrewTT.
Whenever a planar surface is used as a primary datum feature, a flatness control need to be applied to the datum feature, since this will improve the stability between the datum feature and the datum feature simulator, in this way the datum feature A can produce an repeatable datum situation.

Season

 

[SSergey]

Hi Andrew,

I specified MIC-6 which is controlled to +/- .005 in thickness.

Thank you to all for your input! Really valuable and good to know.