# Simple doubt about profile.

• 11-28-2015, 03:02 AM
thilag
Simple doubt about profile.
Hello Friends

Please find the attached excel file.

As per GD&T Standard profile tolerance will not affect the Worst case boundary (WCB), but the attached file contains 2 example simple problems is include the profile tolerance in WCB.

Kindly clarify.

thilag
• 11-28-2015, 06:32 AM
thilag
The minimum distance for "x" is 5.2 and in other example the worst case outer boundary for the 50.2 basic dimension is 50.4. But my doubt is if profile is not affecting the WCB then how this result is possible.

thanks

thilag
• 11-28-2015, 07:15 AM
Kelly Bramble
Question 25

The wall thickness is 6 mm

Each Profile of surface tolerance is bilateral equal, therefore the thinnest wall is equal to:

6
- .6/2
- 1/2
_______
5.2
• 11-28-2015, 07:20 AM
Kelly Bramble
Profile tolerances by default are bilateral equal. Meaning the tolerance boundaries are distributed evenly or symmetrically about the basic dimension location of the concerned surface.

Second example question ..

Outer boundary

50.2
+ 0.4/2
_________
50.4

Inner boundary

50.2
- 0.4/2
_________
50
• 11-28-2015, 07:22 AM
Kelly Bramble
The parallelism is ignored because being that it is a orientation tolerance, the tolerance boundaries will always be contained within the tolerance boundaries defined by the profile tolerance.
• 11-28-2015, 11:22 AM
thilag
I already know how the solution arrived. But my question is i learned as Profile will not affect the Worst case boundary, if so then how it is exceeds the basic dimension.
• 11-28-2015, 12:16 PM
Kelly Bramble
[QUOTE=thilag;11686]I already know how the solution arrived. [/QUOTE]

No you don't...

[QUOTE=thilag;11686]But my question is i learned as Profile will not affect the Worst case boundary.[/QUOTE]

"Worst case boundary" is just a referenced size or location of a surface and conceptually is not bound to any particular geometric characteristic or tolerance.

[QUOTE=thilag;11686]But my question is i learned as Profile will not affect the Worst case boundary, if so then how it is exceeds the basic dimension.[/QUOTE]

A basic dimension does not include a tolerance.. Basic dimension are to be considered tolerance-less or having no variability.

The Profile of surface specification within the feature control frame defines the tolerance boundaries. Those tolerance boundaries are LOCATED bilateral equal or symmetrical about the surface located by the basic dimension.