Question about perpendicularity

[thilag]

Hello Friends

I have a doubt about the perpendicularity. I attached a 2010 excel file <Playing Perpendicularity 031215.xlsx>.

I have a image and 2 stack up questions and answers also plotted. But my question is in first question perpendicularity is taken in account to do stack and in second question it is not considered.

Anybody please explain this.

thanks in advance

thilag

[Kelly_Bramble]

Technically, both questions should require the perpendicularity tolerance to be accounted for.

For question #1 the 30.6-30.0 hole - when the part is setup against the datum simulators - three areas of contact will be obtained from datum A, two against datum C and one area contact against datum D. These areas of contact are the outer-most areas of the as-built feature. Therefore the feature could tilt or taper the entire perpendicularity tolerance closer to the hole feature for datum features C and D.

So, imagine an imperfect part where datum features B and D are as-manufactured within the specified perpendicularity tolerance where the upper edge is at MMC and the lower edge is at LMC relative to the perspective hole features.

[Kelly_Bramble]

BTW - I prefer Minimum wall thickness or distance and Maximum wall thickness or distance as opposed to "Worstcase".

Of course - I'm not the author of your training materials...