Base Alignment Shift from Second Alignment

[[Au...]]

Hi Everyone,

I'm new here and to Calypso, but these forums have been immensely helpful as I am finding my footing. Thank you guys for all the help! 😃

My question involves the use of position characteristics on features taken from a secondary alignment. I have a part I am trying to measure where I need to flip the part over and measure a bunch of holes. I have been doing this with CMM stops and secondary alignments thus far. However, due to the geometry of this part, I cannot position the flipped part back on the table in exactly the same spot as the base alignment position. Additionally, I can only measure the datum features from the initial "top" position because they are inaccessible from the second "bottom" position. I believe I can use the "Special Functions" window to shift the DRF to the second "bottom" alignment, but I am not sure how I would calculate the difference between the two part positions. Any ideas?

[[SH...]]

You should measure datum and features in single setup...

[[Au...]]

Alright, let's say that I hypothetically have a part that resembles a cone without a point on top. There are features (holes, slots, etc.) on every surface of the part. Datum A is the top surface, and datum's B and C are located on the curved surface. For the purposes of this example, let's say the curved surface is rather steep, and B and C (and A) are inaccessible if the part is flipped.

How would I go about measuring this part, particularly for feature positions?

[[Jo...]]

A picture of this would help. There are ways of doing leapfrog alignments, and ways to flip a part and continue measuring with a second model. The location of "flipped" portion is referenced from base alignment so it is possible to offset the flipped model and start another alignment to continue measurements. If you propose a special alignment offset , that is going to be complicated.

[[Je...]]

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Austin,

Those are excellent questions. I think many programmers have had to deal with this scenario.

There is a function in Calypso known as "Base Alignment Match" that may intend to solve this type of problem, but I haven't used it much. I've attached the manual's brief explanation of this function.
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[[Ri...]]

I've only ever used Base Alignment Match on parts that are too long. I'm not certain if it would work, or how well it would work trying to flip a part - I don't think it was intended for that.

[[Mi...]]

Not the direct answer to your question, but a different suggestion for dealing with your issue.

We machine carriers - not sure what you make. And it seems like automakers are getting more and more creative with their Datum Structures.

Due to this we have custom fixtures that load and locate parts in the ZY Plane instead of XY, this allows full access to all important sides of the part with no flips. There are limitations to this especially with XXT machines, even the TL3 only allows for 60mm or so radial direction.

Essentially we get simple custom vises made up to slide onto a small shallow V block. The vises can be changed at will, and still allows us to load parts directly to the V block as needed.

CMM Vise 3.PNGCMM Stand 1.PNG