[Lo...] Posted May 16, 2023 Share Posted May 16, 2023 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. Lou1.PNG Link to comment Share on other sites More sharing options...
[Ri...] Posted May 16, 2023 Share Posted May 16, 2023 You are running into Projection errors. What is your spatial rotation using? Link to comment Share on other sites More sharing options...
[Lo...] Posted May 16, 2023 Author Share Posted May 16, 2023 I am using a circle on X+ towards the end of the part. Thanks Link to comment Share on other sites More sharing options...
[Da...] Posted May 17, 2023 Share Posted May 17, 2023 I'm fairly certain you shouldn't be using a circle as a feature for spatial rotation. Are you sure you use a circle as the primary feature in your base alignment? Link to comment Share on other sites More sharing options...
[Ma...] Posted May 17, 2023 Share Posted May 17, 2023 What is the datum callout for the concentricity spec? Link to comment Share on other sites More sharing options...
[Lo...] Posted May 17, 2023 Author Share Posted May 17, 2023 Dimension on X+ is 16.50mm to the bore of the barrel which is 13.36-13.49mm. And concentricity spec is .100mm Link to comment Share on other sites More sharing options...
[Ma...] Posted May 17, 2023 Share Posted May 17, 2023 Please sign in to view this quote. What is the bore supposed to be concentric to? Concentricity requires a datum reference to be valid. Is the datum the outside of the barrel or some other circular feature? Link to comment Share on other sites More sharing options...
[Lo...] Posted May 17, 2023 Author Share Posted May 17, 2023 Mark, The Datum is the bore of the part 13.49-13.36mm that runs the length of the barrel 164mm. Link to comment Share on other sites More sharing options...
[Ma...] Posted May 17, 2023 Share Posted May 17, 2023 Please sign in to view this quote. Lou, if I am understanding you correctly you are trying to measure concentricity of the bore to itself? If this is the case, the result should be zero. Perhaps a little sketch or snippet of the drawing would help me to understand this better? Link to comment Share on other sites More sharing options...
[Je...] Posted May 17, 2023 Share Posted May 17, 2023 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. Link to comment Share on other sites More sharing options...
[Ch...] Posted May 18, 2023 Share Posted May 18, 2023 I could go on all day about concentricity over a distance. Projection error is your problem here. Read this pdf and see let me know if you have any questions. The real magic starts on page 79ish.Profile_Concentricity_CALYPSO.pdf Link to comment Share on other sites More sharing options...
[Ri...] Posted May 18, 2023 Share Posted May 18, 2023 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. 🤣 Link to comment Share on other sites More sharing options...
[Ch...] Posted May 18, 2023 Share Posted May 18, 2023 Please sign in to view this quote. This is huge. And it doesn't matter how good of a programmer you are; It's a math problem. I've seen cases where when you factor in the stated accuracy of the cmm, then the anticipated projection error is LARGER than the tolerance itself. Link to comment Share on other sites More sharing options...
[Lo...] Posted May 18, 2023 Author Share Posted May 18, 2023 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 Link to comment Share on other sites More sharing options...
[Lo...] Posted May 18, 2023 Author Share Posted May 18, 2023 Please sign in to view this quote. Thanks Chad I will definitely read up on this............and send it to management. Link to comment Share on other sites More sharing options...
[Ri...] Posted May 18, 2023 Share Posted May 18, 2023 Plane1 is not a suitable Spatial Rotation for this part. Even a 3d Line constructed from Circles on either side would be much better and stable. Link to comment Share on other sites More sharing options...
[Ro...] Posted May 18, 2023 Share Posted May 18, 2023 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. Link to comment Share on other sites More sharing options...
[DW...] Posted May 19, 2023 Share Posted May 19, 2023 Please sign in to view this quote. 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! Link to comment Share on other sites More sharing options...
[Lo...] Posted May 22, 2023 Author Share Posted May 22, 2023 Please sign in to view this quote. 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! Link to comment Share on other sites More sharing options...
[Lo...] Posted May 22, 2023 Author Share Posted May 22, 2023 Please sign in to view this quote. Robert, thanks for the reply. I will be able to work on this in a few days. I've tried looking for the the 3D Line feature but can't find it. What am I missing? Thanks Link to comment Share on other sites More sharing options...
[DW...] Posted May 22, 2023 Share Posted May 22, 2023 See pictures. Use ctrl+LMB to highlight both circles after recall.Capture.PNGCapture1.PNGCapture2.PNGCapture3.PNG Link to comment Share on other sites More sharing options...
[Ke...] Posted May 22, 2023 Share Posted May 22, 2023 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 Link to comment Share on other sites More sharing options...
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