***Disclaimer*** - I'm not a machinist

I'm having a hard time understanding why my CMM is showing these results. I'm measuring the concenticity of 2 circles to 1 cylinder. I use the cylinder as my XY origin then probe 23 points for each circle. 1 circle is a little larger than the cylinder diameter and the other circle is much larger than the cylinder diameter. I then dimension X, Y, and Diameter for the cylinder and 2 circles.

I get that my cylinder XY is 0 due to the fact that I orgin'd to it and the diameter is in tolerance. My first circle diameter and X is in tolerance but my Y is dev from nominal by -0.008". My much larger circle diameter is undersized and X is in tolerance but my Y dev is -0.030". So my circles are not very concentric to my cylinder.

It makes sense that the circles are not concentric to my cylinder because a different tool cuts the cylinder and another tool cuts both circles. The problem is that the circles are machined (lathe) with the same tool during the same path/machine operation so production is like no way that these diameters are that far out. I understand that however I've been trying to figure out what I'm doing wrong for over 2 weeks.

I'm using a 7.10.7 with a touch trigger probe. My probes aren't long enough to reach the circle diameters in A0B0 so I have to use multiple angles and vector points. I used auto circle with to points toggled on and made sure I had clearance to hit each point without hitting the part. So the cmm routine is probe comes above part, changes to an angle, goes in and take 2-4 points, comes up, changes angle and so on until I have made a diameter. I've used different probes and different angles, started the a new program and I can't shake this deviation.

I have 12 parts to check and I've only checked 2 but the results are similar. Tomorrow production is going to try and put this parts back in the CNC machine and indicate it to see if its truly off.

My boss told me today that I did something wrong and I know i'm not perfect but it struck a nerve. I've done everything I could think of to shake this deviation and it wont go away.

I'm having a hard time understanding why my CMM is showing these results. I'm measuring the concenticity of 2 circles to 1 cylinder. I use the cylinder as my XY origin then probe 23 points for each circle. 1 circle is a little larger than the cylinder diameter and the other circle is much larger than the cylinder diameter. I then dimension X, Y, and Diameter for the cylinder and 2 circles.

I get that my cylinder XY is 0 due to the fact that I orgin'd to it and the diameter is in tolerance. My first circle diameter and X is in tolerance but my Y is dev from nominal by -0.008". My much larger circle diameter is undersized and X is in tolerance but my Y dev is -0.030". So my circles are not very concentric to my cylinder.

It makes sense that the circles are not concentric to my cylinder because a different tool cuts the cylinder and another tool cuts both circles. The problem is that the circles are machined (lathe) with the same tool during the same path/machine operation so production is like no way that these diameters are that far out. I understand that however I've been trying to figure out what I'm doing wrong for over 2 weeks.

I'm using a 7.10.7 with a touch trigger probe. My probes aren't long enough to reach the circle diameters in A0B0 so I have to use multiple angles and vector points. I used auto circle with to points toggled on and made sure I had clearance to hit each point without hitting the part. So the cmm routine is probe comes above part, changes to an angle, goes in and take 2-4 points, comes up, changes angle and so on until I have made a diameter. I've used different probes and different angles, started the a new program and I can't shake this deviation.

I have 12 parts to check and I've only checked 2 but the results are similar. Tomorrow production is going to try and put this parts back in the CNC machine and indicate it to see if its truly off.

My boss told me today that I did something wrong and I know i'm not perfect but it struck a nerve. I've done everything I could think of to shake this deviation and it wont go away.

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