Legacy TP - NoOK, Xact TP - OK

Recently we had a dispute, for many years we measured a part according to the program sent to us by our collegues from another country, I am forbidden to doubt their qualifications. They used an legacy method for measuring TP, everything was in order until we started having problems with the cnc producing this part, some holes went out of tolerance, for the sake of interest I tried to apply xact and for these measurements it is not ideal but in the tolerance zone, now we do not know what to do, because our parts do not pass through the old dimensions, but the repair service says that it cannot find the problem, I am still a beginner and do not want to go against great minds, but I just wonder how it would be more correct. Here measurements of the same part, and we use iterative alignment.
Have a great sunny weekend everyone

Schrocknroll over 4 years ago

Since there isn't a tertiary datum, XactMeasure is doing a best fit rotation. What kind of rotational alignment are you doing for your legacy position?
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Vladimir over 4 years ago

In both cases A level, B origin, C one of the six holes to Y- according to drawing
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KIRBSTER269 over 4 years ago

In Legacy Datum 1 shows a diameter size Datum 2 doesn't show anything, meaning Datum 2 is a plane. They are calling out

Good news if your callout is correct then they screwed up.

Sorry your new, let me be clearer. D1 stands for first Datum in the FCF, its a diameter, so it is leveling to a cylinder, D2 datum means it's rotating to a line or surface if you switch the 2. D1 would not show a plus or minus value or nominal, because it's leveling on a plane, your examples show the opposite.
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Vladimir over 4 years ago

I don't even know if this is good or bad, because I was strictly forbidden to argue with this, I was told that people there have been programming for 10 years, and you are still small and stupid, in principle they are right, but I hope they will listen to me
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Vladimir over 4 years ago in reply to KIRBSTER269

I understand what you mean, but in that program it is not even aligned in a cylinder, but in a circle
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KIRBSTER269 over 4 years ago

Simple Give them this picture and simply ask them. How does a plane have a Plus .25 tolerance and minus 0.000 tolerance when leveling.
Also how does Datum 2 (D2) identify as a Cylinder with NO nominal and NO Tolerance? Give this info to your boss also.
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Kp61dude! over 4 years ago

I don't even know if this is good or bad, because I was strictly forbidden to argue with this, I was told that people there have been programming for 10 years, and you are still small and stupid, in principle they are right, but I hope they will listen to me

Well listen here "small and stupid" time does not automatically mean you're a giant! (I did sense a bit of sarcasm but just in case you're not). Just go to any 'big name' aerospace company's machine shop and meet some of the cats who have been there for 25yrs plus... I've seen young whipper snapperz in it for a few years walk circles around them, it's sad.
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KIRBSTER269 over 4 years ago in reply to KIRBSTER269

That's even worse, because a circle represents a common center POINT, can't level to a POINT, at least with a cylinder it would be a common center LINE, at least you could level to a line, not the best, but you can.
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KIRBSTER269 over 4 years ago in reply to Vladimir

Well if this is the true callout, and that legacy results are theirs, you can tell them, you aren't arguing with the guys 10 years of experience, but for some reason "the guys" on the forum with over 20 years of experience said he or she is wrong, how about that?
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KIRBSTER269 over 4 years ago

Just another option, If you can't argue with the company that is checking this incorrectly, Then you will have to change your way of producing the part. You will have to drill the main hole and use a Pin to Level the part before drilling the outer holes, Because of the way they are calling it out, The outer holes now become more important to being parallel to datum B, then perpendicular To Datum A, that's what happens when you simply switch the 2 Datums.

Datum_B, MUST be a CYLINDER, NOT a circle!!!!!!!
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