Perpendicularity without form.

[[Mi...]]

I need to report Perpendicularity of Plane to Bore, with Tangental plane modifier. Because Plane to Bore indirectly controls the form of the of the plane.

The problem with that is I'm not confident in how to do it in Calypso, because the plane is a round counterbore.

I recalled the Plane using Recall One Feature to get a theoretical perfect plane, and usually this drops the perpendicularity by what you'd expect.

However it seems the issue now is the reference lengths that show up in the perpendicularity characteristic using the recalled plane, now it appears to be using the entire square plane instead of just the measured points. So the odd time the result appears to be significantly worse than you would expect.

I thought about changing the lengths of the recalled plane to the radius of the circle path used on the original, but this may not be completely correct either.

[[Ro...]]

Instead of recall one feature did you try recalling the actual feature points into the plane?

[[Mi...]]

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You mean Recall Feature Points from the original Plane to the one I want to use for measurement?

RFP keeps the form.

and it won't let me just Recall the original Plane with another.

[[Ro...]]

I'm having a difficult time understanding what you're trying to do. You say the plane is a round counterbore. Do you mean it's the bottom of a counterbore with a circular path? Why can't you use the original plane for calculation? You can change the evaluation type of the plane to anything you want in the Characteristic. Can you post a picture or something visual for reference?

[[Mi...]]

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This is ASME, so perpendicularity of the Plane to Bore indirectly controls the flatness of the plane as well - this is what Calypso does.

I'm trying to use Tangential Plane Modifier, which removes the flatness from the Perpendicularity result.

Since there's no way to put that modifier in the characteristic I need to create a plane with no form, derived from the OTE of the measured points.

[[Ro...]]

Why can't you change the plane evaluation to OTE in the characteristic? I'm clearly not understanding this.

[[Mi...]]

Because that doesn't remove the form error.

"Where the tangent plane symbol is used, the flatness is not controlled..."

[[Jo...]]

I would think the theoretical plane must extend to the full size of the considered feature to be legal. Just because you undersampled it wouldn't mean you can use that probe path would it ? That would be the equivalent of shortening the cylinder axis for better results if done in reverse. If you switched the cylinder to the considered feature and the plane as the datum, it by default eliminates that form error, however that's not the equivalent unless the axis and plane were the same lengths.

Are you selecting the CAD geometry, and does it not maintain that border when recalling feature into it ? OR are you using a generic plane, then recalling measure plane ?

[[Mi...]]

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It's a round 75mm diameter plane. We aren't undersampling anything. We make round parts.

On the real plane it uses the measured points for perpendicularity.

On the theoretical recalled plane it's using the reference lengths and is extending much past the actual plane because calypso is treating it as square 75x75. So that method of "Recall one feature" doesn't work for us having round parts.

So I'm trying to find another way to meet this callout

[[Jo...]]

You posted while I was editing. I don't know what the behavior is if you select the cad geometry then recall. It overides the circular border to be square ?

[[Ro...]]

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I'm interpreting this to mean using a tangential plane for evaluation as opposed to using the entire surface to construct the plane, which is the default. The flatness isn't controlled because the OTE isn't considering the entire surface. That's my interpretation but I could be wrong. Hoping to learn something here.

[[Jo...]]

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OK, I just tested this on a part. If you select a circular bounded plane and then recall a feature into it, it DOES override to a square theoretical. In my case it split the borders because it was bounded inside and out. It appears you can calculate hypotenuse and arrive at a legal "worst case" that mimics your circular boundary limit. That would satisfy my conscience . lol

[[Mi...]]

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Changing the toleranced plane from LSQ to OTE or anything else doesn't change my result (ver. 2018)

I originally hoped it would be that simple.

[[Da...]]

Is this older thread of any help? -> viewtopic.php?t=3342

[[Mi...]]

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That is definitely a very similar situation to what I'm facing, I need to read it slower a few more times but it looks like the corners are a problem nobody actually overcame.

[[Jo...]]

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Try this, Create a theoretical cylinder (from your datum) with an axis length equivalent to your plane diameter (origin at plane). Then use that cylinder as the considered feature, and the measure plane as the datum..

[[Ri...]]

Cant you use a Theoretical Plane?
Form is removed from Theoretical features.

[[Mi...]]

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I actually did exactly that and I'm saving it as a possible solution. The results appear to make sense.

Also, tried creating a secondary alignment with the Cylinder as x,y, and spatial. Then creating a theoretical cylinder on that alignment and using the theoretical cylinder as the toleranced feature and the plane as the Datum.

Both options net the same result.

[[Ro...]]

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Ahhh. Now I remember this. This is good information. Thanks for posting that, Dane. I understand the problem now. Calypso doesn't act the way I would expect it to on this. 😕

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It shouldn't be considering the form error on an OT plane, right? So, is Calypso broken on this? Is this a bug?

[[Jo...]]

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I wouldn't consider Calypso broken, as this is an exception or modification to the default. There isn't an easy "T" button modifier in Calypso so it requires creative methods to deliver the equivalent. It is releasing form from the orientation control.

Profile=location, orientation, form
Parallelism or Perpendicularity = orientation, form
Flatness= form

If you want independent control you use the modifier
An example is a diameter with AVG that releases form from size, then you must apply a form control.