[To...] Posted August 28, 2018 Share Posted August 28, 2018 Sorry for the dumb question..... Regarding measuring the true position of a cylinder. When Additional Printout, formerly Additional Position Results, is activated, what do the X and Y values represent? In other words, where are those values coming from? Link to comment Share on other sites More sharing options...
[Me...] Posted August 28, 2018 Share Posted August 28, 2018 Hmm, trihedron center....scanned points....projection, maybe. I don't know. Good question! Link to comment Share on other sites More sharing options...
[Cl...] Posted August 28, 2018 Share Posted August 28, 2018 Is this what you are referring to? Link to comment Share on other sites More sharing options...
[De...] Posted August 28, 2018 Share Posted August 28, 2018 I just looked at the results of a part with a lot of true positions for cylinders and I turned on axis end points in characteristic settings editor to see if I could determine anything. From what I can see, the numbers provided are not simply reporting the positions of one or the other end of the axis. It appears after looking at it, that the X and Y positions reported with additional printout are the values for the maximum error in each position, which is what you would logically expect. In other words if you do the math to calculate true position on your own using the values provided, you should get the same answer for true position as Calypso provides. Watch out for rounding errors however as this might throw off your answer a bit as I am fairly sure Calypso does the calculation prior to rounding the values. Link to comment Share on other sites More sharing options...
[St...] Posted August 29, 2018 Share Posted August 29, 2018 If you want to confirm the X and Y values you are seeing are the errors in each position use the formula below. Two multiplied by the square root of the deviation from nominal in X squared plus the deviation from nominal in Y squared. You should get the same value you are seeing for the true position. 2 x sqrt (deviation in X² + deviation in Y²) Link to comment Share on other sites More sharing options...
[Da...] Posted August 29, 2018 Share Posted August 29, 2018 Can you intersect cylinder and plane ? Link to comment Share on other sites More sharing options...
[Mi...] Posted August 29, 2018 Share Posted August 29, 2018 they are the axis end of your cylinder showing the greatest deviation from nominal. If you use the "Axis End Points For Position Tolerances" it gives you both ends of the axis including any projection. Link to comment Share on other sites More sharing options...
[An...] Posted August 29, 2018 Share Posted August 29, 2018 _ Link to comment Share on other sites More sharing options...
[To...] Posted August 29, 2018 Author Share Posted August 29, 2018 Please sign in to view this quote. Resources - Characteristics Settings Editor - Axis end points for position tolerances Link to comment Share on other sites More sharing options...
[Cl...] Posted August 29, 2018 Share Posted August 29, 2018 Ok, I'll bite. I went to resources/Characteristics editor/Axis end points for position tolerances. This option is greyed out, won't allow me to select on, or off. Also what do I get if I was able to turn this on? Link to comment Share on other sites More sharing options...
[Ri...] Posted August 30, 2018 Share Posted August 30, 2018 Andreas,, Calypso calculates the axis end points by creating a circle center at one end of the measured data and another circle center at the other end of the measured data. The X and Y or Y and Z or Z and X values presented are a aid to any process adjustment that might be necessary. Link to comment Share on other sites More sharing options...
[Ri...] Posted August 30, 2018 Share Posted August 30, 2018 Clarke, it should be active. You have to have cylinder or a cone on your feature list and a Position Characteristic for either a cylinder or a cone on the Characteristic list. What you will get is the X,Y or Y,Z or Z,X values of the cylinder or cone center line end points. These might be helpful if you need to communicate a machine move to your CNC operator. Link to comment Share on other sites More sharing options...
[To...] Posted August 30, 2018 Author Share Posted August 30, 2018 Please sign in to view this quote. Clarke, Can you post a screen shot? Link to comment Share on other sites More sharing options...
[An...] Posted August 30, 2018 Share Posted August 30, 2018 _ Link to comment Share on other sites More sharing options...
[Mi...] Posted August 30, 2018 Share Posted August 30, 2018 I found that if I select or have selected either "Group in custom printout" or "Formulas in default printout" it greys out the other selections. I click on the "Additional Printout" then OK out, then back in and everything will be fine. Or change Accept for: to selected features. Link to comment Share on other sites More sharing options...
[Mi...] Posted August 30, 2018 Share Posted August 30, 2018 Please sign in to view this quote. Good question. I kinda figured it depended on how the feature was evaluated. Link to comment Share on other sites More sharing options...
[To...] Posted August 30, 2018 Author Share Posted August 30, 2018 The circles/end points are calculated based on the evaluation setting of the feature in the position. I just performed the following test to verify Richard's description. I created an intersection of the cylinder shell and the top plane. The X&Y values were the same as one of the axis end points. The diameter and projection angles of the intersection were the same as the cylinder. To check the bottom, I created a theoretical plane at the cylinder's nominal depth. The X&Y values were the same as the other axis end point, and the diameter and projection angles were the same as the cylinder. In my test, all evaluations were LSQ and then again at OTE. To review, I don't think the issue is whether it creates circles at the end points, but rather it creates intersection points at the defined end planes of the cylinder. And those intersection points are where the axis end points are defined. Link to comment Share on other sites More sharing options...
[An...] Posted August 30, 2018 Share Posted August 30, 2018 _ Link to comment Share on other sites More sharing options...
[De...] Posted August 30, 2018 Share Posted August 30, 2018 I don't get why this is surprising. True position is a tolerance zone that the axis of the hole must remain inside of. It is not a point at one Z height, it is a zone the length of the cylinder. Given this is the case, how else would Calypso determine if the entire axis of the hole fell within the zone. If you have any angular error of the axis of the hole, then projecting the axis out farther the error will be multiplied as the length increases, the opposite is also true - if the cylinder length is decreased, the error will also be reduced. If the hole is perfectly aligned with no angular error to the nominal hole axis then the error would remain the same regardless of the hole length. This is the entire reason that projected tolerance zones are a thing. Link to comment Share on other sites More sharing options...
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