true position

[\v/inston]

iterative alingment three hole DAT-B-, DAT-C-, CIR6 (DAT-C- and CIR6 are cast from the slots).

the trihedron is 3D and NOT square to anything and since the print is 3D and NOT 2D. how do you dimension the true pos. if I use XYZ and DATUMS ABC then the TP looks like sh*t, like 8-9mm out of spec. the TP calculation is for deviation in 2 directions X&Y perp to A right? the part fits the fixture, the fixture checks good, the stab pins all go with no problem, but pc-dmis says the holes are bad.

[\v/inston]

...

[Jeffrey Lovely]

match

check the cad model vs print vs gage
since we both work at the same company
I bet it dont match !!!

[Paul Sarrach]

True pos is 2d. do not use the surface axis.

[Jeffrey Lovely]

if using the gage for set up -check your tooling ball numbers

[Matthew D. Hoedeman]

In the TP dimension itself, there is a toggle option for PERPEN to CENTER LINE, toggle this ON to simulate a stab pin in a fixture.

[Jeffrey Lovely]

I have a program for that part

[\v/inston]

the print has no 2D basic dimensions to use for the true position alignment. jeff that is the print in the picture. and i forgot to say that i am checking in the freestate.

[kbotta]

Winston,
Are there basic dimensions on the drawing (somewhere?)?
If not remember this. The tolerance zone is normal to the hole, or in other words, they have 'parallel axis'.
You need to get the trihedron looking down the axis of the hole (nominal) and then report/measure the feature. Position in 2-d, check the perp seperatly (or check position in 2 places).

So, with rotations, offsets etc... you need to be 'normal'

I'm not normal. Just ask....
Kev

[Jeffrey Lovely]

222 part ?

[\v/inston]

jeff send it over


matt -> http://www.mmiclan.com/smilies/vb_notworthy.gif

[ag162]

I agree with Matt. Also, just for a sanity check, put the part on the fixture, use the fixture alignment and check the out of tol areas. Apples to apples.

A.Gore

[kbotta]

Use your math data to find the rotation (nominal) so the cmm looks down the nominal axis of the hole. find the basics from that...
kb

[Jeffrey Lovely]

looking for it

[\v/inston]

yes 222