Y14.5 - 2018 Dynamic Profile

[[Ja...]]

Little confused here. Y14.5 - 2018 Dynamic Profile. Specifically 11.10.2 (Figure 11-36) VS 11.10.3 (Figure 11-37).

In 11.10.2 a composite Profile control is used and the dynamic profile tolerance zone is allowed to translate relative to datum B.
In 11.10.3 a "Two-Single-Segment" Profile control is used and the dynamic profile tolerance zone is not allowed to translate relative to datum B.

What is the difference here? Really, why is the zone allowed to translate relative to B when it is a composite control?

[[Br...]]

In figures 11-36 and 11-37, the lower segment references AB, not just B. So just forget about dynamic profile for just a minute. If this[figure 11-36] was a composite profile tolerance without the dynamic profile modifier, what would it mean? It would mean that the upper segment is treated like a typical profile tolerance to ABC. Then lower segment has a tolerance zone of 0.4 and Datums A and B constrain its rotation and the tolerance zone is free to translate.

Now what would figure 11-37 mean without the dynamic profile modifier? We have two separate segments, so they should be treated as two seperate profile tolerances, one in reference to ABC, and one in reference to AB. (No freedom to translate because it is not a composite tolerance.)

Now all the dynamic profile modifier does is give the profile the freedom to expand and contract (i.e. change size), on top of what we already understand about composite and single segment profile tolerances.

So your question has nothing to do with the fact that a dynamic profile modifier is present in these figures. It's simply the way composite tolerances vs. single segment tolerances work.

[[Ja...]]

Thanks Brett,

That is what I was worried about, I wasn't sure if it was unique to dynamic profile. So if I am understanding this correctly - The top line of the composite control is locating the entire pattern relative to the datums/basic dims but the second line creates a zone that is free to move around within the pattern locating zone without explicitly being constrained to datums? In the case of two separate segments, each line has to adhere to it's datum constraints as is typically done?

[[Br...]]

Please sign in to view this quote.

It's free to Translate. The rotational degrees of freedom are still constrained relative to the DRF in the lower segment, but the translational degrees of freedom are unlocked.

Please sign in to view this quote.

Yes, treat them like you normally would any other single segment feature control frame.