Position control with only one datum
Position control with only one datum
(OP)
A simple question but need your comments.
Please ref to the attached sketch, it's a zinc alloy die casting part, can we use position control to locate the tab with only one primary datum? The designer intends is to control the centerplane parallel to the datum A or just its location?
Thanks for the assists
SeasonLee
Please ref to the attached sketch, it's a zinc alloy die casting part, can we use position control to locate the tab with only one primary datum? The designer intends is to control the centerplane parallel to the datum A or just its location?
Thanks for the assists
SeasonLee





RE: Position control with only one datum
Frank
RE: Position control with only one datum
As for second question, based on what is shown his intent is to control both - loaction (position) and orientation (parallelism) of centerplane relative to A. Simply because position indirectly controls orientation (but not opposite).
RE: Position control with only one datum
You caught the point, the problem is on the basic dim.
SeasonLee
RE: Position control with only one datum
Sorry, I should say both of you caught the point.
Thanks
SeasonLee
RE: Position control with only one datum
RE: Position control with only one datum
Can it be exchange to symmetry or parallelism for both tab's surfaces?
RE: Position control with only one datum
pmarc?
Frank
RE: Position control with only one datum
RE: Position control with only one datum
Frank
RE: Position control with only one datum
I guess I am not suprised we disagree. I really do hope you are not M. Foster from yahoo GD&T group.
Frank
RE: Position control with only one datum
Look to para. 7.2 of Y14.5-2009. It clearly states that: "Position is a location of one or more features of size relative to one or more datums".
Now, 1.3.32.1 says: regular feature of size is "... a set of two opposed parallel elements or parallel surfaces, each of which is associated with a directly toleranced dimension".
That being cited, basic 6.00 would not be directly tolerance dimension, therefore would not meet feature of size definition, therefore could not be controlled by position callout. Does that make sense?
RE: Position control with only one datum
Thanks,
Frank