Polyworks problem

[Alan Lowbands]

Hi guys,

I was hoping someone will be able to help with a problem with a polyworks report.

It was created from a scan and reports the positions of 4 lifting attachments.
The problem is it's reporting the position and diameter symbols but including an S symbol.
I assume this is spherical symbol but not sure why it's there.

If anyone can help it would be really appreciated.

thanks
Al

 

[Alan Lowbands]

Belanger,
Thanks for the reply.

You may be onto something there.
The position they need to report is a point where the cylinder intersects the top face of the equipment.
I've no idea why it would do that but I wonder if this is why it's calling it?

regards
Al

 

[Burunduk]

If the controlled element is a point it is reasonable to have a spherical tolerance zone for it. But it is unusual to derive an intersection point from a cylinder and a face and control it by position. This is not a standardized practice, and the way to do that may be open to interpretation. For example - should the axis intersect a tangent plane or a best fit plane? Etc.

 

[3DDave]

They are reported spherically because someone told the software that was what the feature control frame was controlling.

That is an input to the CMM software by the CMM operator or by importing the model.

 

[axym]

Al,

As 3DDave has pointed out, the numbers don't add up. I'm not able to figure out how the 1.822 and 2.328 values were calculated. They don't represent the diameter of a spherical zone based on the X and Z deviations - there must be some other math going on there. If we assume that there are unreported Y deviations, by my calculation they would have to be 0.248 for Point 1 and 0.686i for Point 2.

So you could say that the results are complex - there is literally a real component and an imaginary component. ;^)

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca