Alignmnet with two tooling balls

[A Disho]

I get always fixtures with three tooling balls, which I run iterative alignment ,
I have in a fixture with two tooling balls,

1-One tooling ball called master with x,y,z and one extra reading ( 10601 lh p2)
2-Second tooling ball called secondary with x,y,z, and same extra reading(10601lh p2)
3-The top of surface has three locations as circles with ( this surface 100 to POR).
4-Side of the fixture block has reading ( 370 TO POR ).
5-End of the fixture block has reading ( X 4030 REF.).
What POR means. what is the best alignment ,please give me details in steps.

A Disho

[Matthew D. Hoedeman]

Measure a plane in the 3 circles, measure the side stamped 370 to POR, then measure 1 tooling ball. Simple 3-2-1 alignment, level to the plane, rotate to the line, set XYZ origin at the tooling ball

LEVEL = PLANE
ROTATE = LINE
X ORIGIN = TOOLINGBALL
Y ORIGIN = TOOLINGBALL
Z ORIGIN = TOOLINGBALL
X OFFSET = opposite of amount stamped, ie if the ball says X=1200, then use -1200 for the offset
Y OFFSET = opp. stamped amount for Y
Z OFFSET = opp. stamped amount for Z
CAD=PART (you MUST do this)
end of alignment.

[A Disho]

alignment

Matthew,
Thank you for quick help.
why did they put two tooling balls in this fixture,
Thanks

[Matthew D. Hoedeman]

Well, what are the numbers on the balls?

Does this fixture hold 2 parts (rh and lh maybe?)

Just a couple questions, if it does hold 2 parts, one will be for the part, and the other for the other part.

Also, it may be set up so it can be easily aligned by different machines, horizontal or vertical is a possibility, but unlikely in my opinion. But, in any case, 2 balls is not enough as you well know, or you wouldn't have posted to begin with! IT is also possible that you wil need to use the 2 tooling balls to construct a line for you to rotate to instead of the side of the fixture.

[Lawrence Hardtacke]

I have a customer who insists their fixtures be built this way. As Matt said use the three inscribed circles for your plane. One of the tooling balls is intended to be used as the Origin (marked as CMM Start, Master); the other tooling ball is there for the creation of a line for rotation during alignment and has no other purpose that I am aware of.

This customers fixtures are built to these datums and always rechecked to an alignment created from them.

The edges of the fixtures are reference only.

[Matthew D. Hoedeman]

Well, if Lawrence (may I call you Larry?) is correct, I would suggest using the 3-D line for the construction between the balls. This will keep Pcdmis from 'forcing' the line into any workplane, then when you use it for rotation, it WILL give the correct value for the rotation axis. Sometimes, when doing this with 2-D, it will not quite work out right since the line is being constructed in an alignment PREVIOUS to the one you want to use. 3-D eliminates this.