straightness / flatness tolerance
 

http://www.eng-tips.com/viewthread....d=258473&page=1
pete6696 (Mechanical)7 Nov 09 5:29
I am trying to place a straightness / flatness tolerance on a flat circular rubber part (dia 40mm) to constrain the amount of warpage allowable. The part is 2mm thick with size tolerance of +/-0.1mm. It is acceptable that the part warps +/- 1.5mm (z-axis) in either direction for it to pass. 1) Is the straightness / flatness tolerance allowed be greater than the 'size tolerance' or do I need to use a different tolerance type? 2)I am unsure whether I should use straightness / flatness, what determines which one I use?