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Concentricity

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By [Lo...] ,
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[Lo...]

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Hello everyone,
I have a concentricity issue. I attached a picture below. On the barrel I am checking a circle on either end, the dimension is 13.49-13.36 and the length is 164mm. Dimensionally the circles are with in tolerance but when I check concentricity I am getting some numbers that don't make sense. Tolerance for concentricity is .100mm. The results range from .500mm to .745mm. I have tried using a cylinder to circle and getting better results but still pretty far off from the .100mm tolerance.
I know this can't be correct, because I have a gage pin the same length and it slides straight through the barrel easily.
What am I missing here? Thanks for the assistance.

Lou

1.PNG

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[Je...]

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Based on the statements, I am guessing this has to do with the relative alignment and an error in projection over length. If you evaluate the datum as a cylinder at full length (measuring both ends) rather than a circle, does this impact your results? Im willing to bet your local alignment or base alignment are not properly capturing the features axes. If this is just evaluating 1 circle on 1 end to another circle on the opposite end, I am certain of it. Also willing to bet that the results vary wildly with each run.
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[Ri...]

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I'm finding more and more issues with results that stem from projection error - even in cases where you wouldn't normally think it would have that significant of an impact.

Been working on a part for a customer where the datum structure is based off two holes spread .250" apart, and then you project them 6' (yes 6 feet) away to check a position. 🤣
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[Lo...]

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Everyone,
I appreciate all of your replies and I apologize for any confusion. Please bare with me on this. So the SAT file I am using for one reason or another is not correct when I have my base alignment it seems everything is shifted. For this particular part I am having to work with engineering on the other side of the globe. So I gave up on it and have done it manually. I am also dealing with management that for whatever the case may be hates Zeiss yet has little experience with it other than a short time in the late 90's. Allegedly! I was told to do two circles on either end, well aware this is not going to work, it's a thin wall aluminum part and it's not even a good clean machine surface inside. Sorry for the rant, I feel better!

So I have done a manual inspection on this part. I have attached a picture of the alignment and features. Circle one is on the end of cylinder one....my bad! So per print Datum A would be the length of the tube circle 1,2,3, or cylinder 1,2, with a centricity call out of .100 mm to a dimension which I do not have in the picture which is 16.50mm. Management changed the print to do a concentricity on Datum A to Datum A using a circle on either end 164mm apart. I know this is not going to work but I was over ruled. Obviously when I do a concentricity to circle 1 and 3 the results are .450 roughly and are inconsistent. Now when I do concentricity to cylinder 1 to circle 3 the results are .0845 roughly and is to print. I do appreciate everyone's feedback. Sorry again for the rant, but I'm glad I got this off my chest.

Thank you!

Capture1.PNGCapture.PNG

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[Ro...]

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To add to Richards post...

Measure a circle on each end of the part on the datum surface. Create the circles as far apart as possible for a stable alignment. Create a 3d Line and recall (not recall feature points) the circles into the line. Measure a plane on the end of the part. If there is a clocking feature (looks like Plane 2) then measure that if you want to clock the part.

In your Base Alignment use the 3d line as your Spatial, Y, and Z origin. Use the Plane on the end of the part as your X origin. Use the plane on the side as your Planar rotation if you want to clock the tube.

Now measure your Datum cylinder gathering as much data from both ends as possible. You can do circles and recall them into a Cylinder, or check it as a cylinder with move points, clearance moves, etc. to navigate both sides of the part. Do the same for any concentric diameters you need to check.

Evaluate and you're off to the races.
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[DW...]

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He hates Zeiss and Calypso because he does not understand the software. I've been there. Learning new software can be very challenging and becoming frustrated is normal. When I was first introduced to Calypso, my coworkers who had been working with the software for some time would refer to it as if it were a person. As if it had a mind of its own. "Calypso doesn't like that" or "Calypso sometimes does that." I was determined to take the mystery out of the software. It's a program, it does what you tell it to do. I studied the help files, read every post on these forums, took all the online learning courses (free and paid) that I could get my hands on. I became very comfortable with using all that it had to offer. Now, my employer is regularly surprised when he asks if I can do a task in Calypso, and I'm like "Yup, no problem. Check this out." The software is good stuff; so become the guru not just to quiet down the boss but to build your confidence with the software and with your position. Best of luck!
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[Lo...]

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100% Devin!
I do my best to keep learning what I can I dang near begged them for more training. I always to try to make time to get on the CMM but unfortunately it collects more dust than it runs. But I ask questions and try and do the research. I am very thankful for this forum!
Thanks!
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[Ke...]

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Pay attention to the order you select the circles for recall-The first one clicked will define the origin point of the line, the second defines the direction.

Lou-I appreciate your desire for more knowledge and training. Have you checked out the free videos available in the Zeiss Academy section of the portal? https://portal.zeiss.com/academy/video-tube/imt

There is also the Zeiss Metrology Youtube channel, which may have some information of value to you as well
https://www.youtube.com/@ZEISSACADEMYMETROLOGY/videos

Lastly, here is a link that has additional information regarding our trainings, which might help convince management
https://experience-metrology.zeiss.com/ ... /portfolio
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