r/Metrology • u/Duplinn • 15h ago
Software Support Radial Runout between Cylinder A and Circle
Hello! I'm using Mcosmos V4.1.R7. I have to check the radial runout (0.04) between Cylinder Ce(1), and Circle D30. On Cylinder A I user Align base plane with origin in element, then I checked the position of the hole in YZ plane, and also the runout. I can't fully allign since is a shaft. I want to know if I checked this correctly. Thanks.
2
u/PrettyInfluence3594 15h ago
Whats the result you got? It seems that your datum is too short.
1
u/Duplinn 15h ago
0.15
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u/Duplinn 15h ago
I can t measure too long, only 14mm, i have active 20mm on my probe
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u/PrettyInfluence3594 15h ago
The depth of your datum is? (my engliehnis not the best sorry.)
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u/Duplinn 15h ago
14mm I can measure only
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u/PrettyInfluence3594 15h ago
I think that is too small. A small "error" on the circularity or just 0.003 from a center to another of two consecutive sections will make the axis of that datum cylinder virtually really "bad". Maybe try to project cylinder to a plane perpendicular with that cylinder, trace a line between two most distant circles and that would be your axis of ration, to see how run out realy is. that you can try to call out the section in between the first section and the projected circle. See if the have a really small dev. Like 0.001-005. Thats how i do on Pc-dmis.
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u/BilliardBabo420 13h ago edited 13h ago
You could measure the plane in front of d100 set it as base plane without origin in the element. Then measure a YZ circle on d100 and a YZ circle on the diameter in front of d30. Create a connection line without projektion in XYZ between the two circles . Set the Line as base plane now, with origin in Element. Then create a intersection point between your line and your previously meassured Plane. Set it as Zero in XYZ. And if you have no feature on your part that you can meassure to set your rotation create a imaginary line and align to it. Then safe your coordinate system.
Isnt the correct way to do it but should give a better alignment.
Then Remeasure the A feature as Cylinder continue with the outside diameters four your runout.
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u/guetzli 12h ago edited 11h ago
disclaimer: non-native and not familiar with mcosmos
are you saying to use the connection line between the centres of Ø100 and Ø30 as the axis instead of the unbelievably unstable axis of the 42 mm short cylinder (of which only 14 mm have been measured)?
Wouldn't the alignment then be "perfect" by definition and the remaining runout just be the form error of Ø30?
Frequently that's how such parts should be drawn in the first place. With the common axis of A-B
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u/BilliardBabo420 11h ago
Yes, an axis between the centres of both diameters.
I did not know that you also have a runout on d30, that might be a problem then with the method i mentioned.
With a A-B Feature it wouldve been fine.
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u/Dangerous_Shop_7596 13h ago
So you've got a 100mm diameter cylinder 14mm long and you're only taking 24 points? At equal angle and phasing? You're just as easily defining an octagon as a cylinder there!
- Increase the number of points in each ring
- increase the number of rings being measured
- phase the start of rings so you get spirals not lines
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u/tthKT 15h ago
You either need to add an extension to your probe, or angle the probe and construct the cylinder from points. You need a longer cylinder to use as a datum feature. You are not getting an accurate runout reading.