slot as a secondary datum with MMB

[MikeF]

is there a way to use a round slot feature as a secondary datum with rotation and shift? MMB

[neil.challinor]

This is discussed in the following posts

https://www.pcdmisforum.com/forum/pc...lot#post450165
https://www.pcdmisforum.com/forum/pc...ogy#post473133
https://www.pcdmisforum.com/forum/pc...d-c#post473489
https://www.pcdmisforum.com/forum/pc...ums#post471372

[MikeF]

I constructed a 2D width feature for the secondary and in the out put it shows fixed

[neil.challinor]

Not sure I understand. Can you post the drawing (or at least the section of it that shows what you are tying to do) and your code?

[MikeF]

see attached drawing, I want to use datum DJ shift and rotation

[neil.challinor]

OK, I assume its the bottom LH callout for the 4x tapped holes - Position| Ø0.4 MMC |R|DJ (mmc) |H. I can't see datum H on the section of drawing you've posted but datum R would need to be a plane and for datum DJ you need to measure each of the slot sides as planes and then construct an inner 3D width from them.

[KIRBSTER269]

Not seeing H, but since it doesn't have Max Material. It's going to lock rotation so there is no Rotation, best your going to get is shift on one of your Datum's.

Actually the slot would control Rotation my bad, but it wouldn't allow it it to rotate? it would set a boundary of 2 planes to lie in? Brain fart monday. maybe shift but no rotate?

Click on customize to see what PC-Dmis is doing, might have to change things in there. Capture.JPG

[MikeF]

I tried using a 3d width feature for datum DJ seems to work but it flips trihedron around

[neil.challinor]

XactMeasure shows a trihedron that represents the datum reference frame. It tends to make the direction of the primary datum ZPLUS (internally it is creating an alignment that levels ZPLUS to the primary datum feature). Select "current alignment" rather than "datum reference frame" on the advanced tab when creating the dimension if you want to display the coordinates relative to your existing alignment.

[oddam]

When I have to rotate to a round slot, majority of the time it's locked in the width. I measure the slot with sample hits and if pierced, measure the shear, then construct a sphere. The sphere will be centered of the slot and as wide as the width only. I then align to the 3d sphere locking in the rotation. The iterative alignment seems to prefer a 3d feature, but I have also constructed a point also, it works for me.

[KIRBSTER269]

Finally showed up to the party, That's what I was thinking in post #7. but with Max Material will allow shift in 1 direction with it having a third datum feature not allowing it to shift in the other.

[MikeF]

If I use a 3D width feature and the DRF option it works, it rotated and shifts just flips the axis around, if I use the current alignment option it does not work.

[KIRBSTER269]

Of course that won't work, That first one is a fixed location, only allowing the diameter to move in 4 directions. That will never give you any bonus. If you want to see what it looks like in Legacy disable Xact. Xact will setup a 3D boundary allowing it to move in any direction with in that boundary.

Untitled.png

Click on this to use Legacy position, and don't pick Datums if you want to use current position or alignment. If you pick datums in Legacy, pretty sure it don't recognize widths.


Capture.JPG