Roll,pitch,yaw

[[ch...]]

I would like to know more about geometrical errors specifically the roll pitch and yaw. I know it error is related x y z Axis rotation.
My question is how CMM metrologist calculate these errors??.
Can any experience operator understands these errors using ordinary observation??

[[Er...]]

Not sure I understand what you mean by "calculate these errors". But you can "calculate" them by determing the rotation a round the specific axis. Isnt this used to describe the movements of a plane or a helicoper?

But in metrology we usually describe rotational difference between to coordinate systems with euler angles. I usually use a matrix if I have to solve it my self.

Did a quick duckduckgo and found this. Pretty self explanatory.

[[ch...]]

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I was talking about CMM angular errors, I don't know how CMM engineer calculate it. Euler angle is used in spherical co-ordinate system?? I think we can convert it into Cartesian coordinate system using i j k vectors.

Screenshot_2020-03-28-22-09-31-67.png

[[Er...]]

Are you talking about the cmm it self? And its squareness error?

Like machine moves 10mm in only +Y. But since there is squareness error, it's actually now located in X0.0002 Y9.9999 Z-0.0001.

The principle is not that hard to understand. But since the error most likely isn't linear, it gets very complex. And I dont know exactly how Zeiss (in this case) determine thire values for "computer aided accuracy" I know the use prisms and laser. But the rest is nothing they share I guess.
And I know no details, so I cant help you with that.

Otherwise, I still dont know what you are asking.

[[ch...]]

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Yes, iam talking about CMM itself. In my company they are using step gauge for calibration not laser technology. Roll , pitch,yaw are errors in CMM. But I don't know how they measure it.

[[Er...]]

Okey now I see. They are measuring gague block to see if the machine is within the limits of MPE.

I have never heard of this error described as pitch, roll or yaw.. To me its presented as either linear error per lenght in one or more axis MPEe, or as roundness error RONt, or scanning respecting probing error, MPE-THP/MPEp. (Or something like that, not sure I remember the actual mpe-names)

Small correcttions can be done. But if the machine squareness is to big. They bring in the laser.

Maybe someone with more knowlage of this particular area can help you better. But one guess is that they use trigonometry to convert length error to angular error in your case. And since the errors probably isnt linear, it sounds stupid. But I have no clue.

[[Ro...]]

I agree with Eric
I've had lots of "Lathe Parts" that are turned and have holes/slots drilled into the side using live tooling that needs to be clocked to a datum, we never use the terms R,P,Y we just communicate
Me "Yo you need to move these holes counter clockwise by a couple degrees"
Operator "counter clockwise from what end?"
Me "As it site in the machine"
Operator "My machine?"
Me " No, The CMM, look how its fixtured in the CMM"
And then we do a lot of hand gestures to each other so we both know what direction the holes need to move.

[[SH...]]

I have seen a youtube video , that a ziess engineer disclosing about these errors to another person. These errors are related to the structure of the CM M machine. I think parameter like coefficient of thermal expansion might influence these errors. I think CMM operator or programmer can't do anything on this errors. These problems are corrected during CMM calibration.

[[Ma...]]

The CAA error map for our Zeiss bridge CMMs (older lab grade machines) are determined with a laser interferometer system. This is done at the Zeiss factory and if and when necessary in the field. Five of the six degrees of freedom for each axis are measured with standard laser interferometry optics. Roll deviations cannot be measured with the standard optics package and require some special equipment and are typically not measured in the field.

[[Kl...]]

A short "shopfloor" handout about CAA and what's possible at costomer side