Position: Independent Tolerance According to Radial/Angular Location

[[Ri...]]

I got a fun one. A dual Position callout on a pattern of holes where they want a specific tolerance for the radial location, and another for the angular location. 

Apparently this is achievable in certain DMIS based softwares, but not easily achievable in Calypso. 

Thoughts?

[[Ma...]]

Can you post sketch? Perhaps i'll VOODOO something 😄

[[Ri...]]

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Since I needed Datum Shift - here was my first stab at it. 

I created a Bore Pattern Position that allowed Datum Shift. 

Then I created individual Position callouts that referenced the Bore Pattern as the Datum. I then rotate each one to the nominal angle of the hole, and evaluate the X/Y Position independently.

I wanted to new the GD&T Position, but the Simultaneous Evaluation is not very optimized, and it doesn't allow separate tolerances per direction like the original Position does, so I'd have to double the amount of characteristics which in turn makes the Simultaneous Evaluation even slower.  

[[Ma...]]

Is that part like cylinder in Z axis and holes in Z axis, or cylinder in Z axis and holes from shell of cylinder to center?

[[Ri...]]

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Just imagine a bolt pattern of holes on a flange. They lie in the X/Y plane. 

A = Top Plane

AE = Center Diameter

C = Clocking Hole

[[Ma...]]

Ok, now i have a vision 🙂

I wonder - what if they inteded to use rectangle tolerance? Having hole on top ( aka X=0 Y=radius ) and tolerance X=0.06 and Y=0.03?

And i forgot one mention - there is no Ø sign

Edited February 18

[[Mi...]]

I think your plan is good, it makes logical sense to me, as I saw you commented elsewhere PCM will almost definitely help make this a less arduous task

Except is there going to be a problem with the fact that X and Y will not quite equal radius and angle? Don't bring it up, because I'm pretty sure there's no way to have a rectangular tolerance zone with the Feature set to Radius and Angle.

[[Ri...]]

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Yes - you are correct - the only logic that I could put to it is it's the same way that we evaluate Position on a Slot. I've been asking for a way to do Angular Position only, but no success yet. 

[[Mi...]]

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We would use the crap out of that.

 

When I'm giving the machinists offset values, like average clocking of the pattern in a situation like this, I end up using trig and a result element to give them a single Angular value to adjust to. It's fine, but I either need to recall the feature in question into a correct secondary alignment ( something I'm allergic to due to the chaos of programs I've had to deal with) or use PCM to pull the values from hidden Position Characteristics... It all works but I wish it was simpler. 

[[Da...]]

But...why would each have a different tolerance? When you are doing cylindrical coordinates, you are not dealing with mm's and degrees, you are going for a round tolerance zone around a theoretically perfect point either way. The number you get SHOULD be the same.........

[[Ma...]]

I personally think that this callout should be evaluated as one with rectangle tolerance - text there is telling in which direction is which tolerance.

But in doubts i would contact customer for clarity.

[[Ri...]]

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The customer's legacy equipment can easily handle this callout. 😞

 

T(A_HOLE_ANG_TP_.06)=TOL/POS,3D,0.06,MMC,ANGLE
T(A_HOLE_RAD_TP_.03)=TOL/POS,3D,0.03,MMC,RADIUS

 

[[Da...]]

So, under Size>Standard> there are polar positions for radius, angle, and height. Would you not use these for each hole? The radius position sits on a bolt circle with each hole at an angle from the clocker hole. The radius distance is from the centerline A-E. I think you would have to have each hole positioned individually. You could check the group to the bolt circle, but the angles need to be evaluated separately. 

[[Ch...]]

Kind of like with X/Y position Calypso allows you to select position in X or Y only - but I don't believe these options are available for polar features. We should request it on MyVoice.

 

I would probably rotate to the feature so in cartesian it is on X or Y, then report X + Y individually and rename them as RADIUS + ANGLE etc.

[[Da...]]

Does Calypso actually call Cylindrical components "polar"? I still remember my dynamics professor banging into our heads the 3 different dimensional systems: Cartesian (X,Y,Z), Cylindrical (Radius, Azimuth angle, Z), and Polar (Radius, Azimuth angle, Zenith angle). 

[[Ch...]]

I tihnk in some places they do call it polar, and in other cylindrical ...

[[An...]]

I've heard spherical coordinates called spherical polar coordinates, but I've never heard cylindrical polar coordinates.  Worse than odd naming conventions are the mathematicians who flip the polar and azimuthal angles. Or the physicists who decide their new textbook needs to be "different" and uses the elevation angle instead of inclination as the polar angle and make the whole darn coordinate system left-handed for no reason. 

Edited February 20
Clarity