Profile, variations of evaluation methods

[[Tr...]]

Howdy all,

I have a problem that I have been trying to tackle but the numbers just aren't adding up.
I have exhausted too much time and mental energy so I decided to create a post.

There is a variation between how I am constructing a profile measurement and how our supplier is constructing the measurement.
We are both using calypso and I have ran through both programs.
We have spent multiple hours conversating about the issue and our team has tasked me with figuring out the difference between the methods.

So, to start out the material is cast and in the past has had issues with warpage.
The intent of the measurement is to control form variation of plane/Datum S and it's distance from Datum K.
Evaluation Method for Datum is Outer tangential feature, Ref. calculation as per ISO 5459 is on.
We have a Datum that is a compound plane across 6 surfaces, this plane has an average form of 0.09mm and a sigma of 0.02 mm.
This Datum is created by recalling the feature points of 6 individual plane features.
The Datum Nominal values are as described on the print. (deriving from other datums across the part)
We shall call this Datum K.

I have constructed an additional alignment with Datum K establishing rotation in space and the Z axis. (Everything else is left blank)
Lets call this Alignment 1.

I have constructed another alignment with Datum K establishing only Z. (everything else is left blank)
Lets call this Alignment 2.

There is a Bilateral Profile call out that is compounded across two surfaces. (of equal distance deriving from Datum K)
This Profile tolerance is 0.50 mm with respect to Datum K.

A plane is constructed to recall the feature points of the 2 surfaces(S1&S2). (Nominal values reflect basic dimensioning on print deriving from Datum K)
Lets call this plane Datum S. Plane S1 (RFP) +Plane S2 (RFP)= Plane/Datum S

A Freeform Surface is constructed by recalling the feature points of planes S1&S2.
Lets call this Freeform S

The variations of the callout with in calypso are as listed below:

-Profile of Plane S held to Alignment 1
-Profile of Plane S held to Alignment 2
-Profile of Plane S held to Datum K, Datum K, Datum K

-Profile of Plane S1 held to Alignment 1
-Profile of Plane S1 held to Alignment 2
-Profile of Plane S1 held to Datum K, Datum K, Datum K
-Profile of Plane S2 held to Alignment 1
-Profile of Plane S2 held to Alignment 2
-Profile of Plane S2 held to Datum K, Datum K, Datum K

-Profile of Freeform S held to Alignment 1
-Profile of Freeform S held to Alignment 2
-Profile of Freeform S held to Datum K
-Profile of Freeform S held to Datum K, Datum K, Datum K

Which is the most accurate reading?
The supplier is also not having Datum K deriving from where the print calls out.
They have constructed their own base alignment ,which is fine, but they have no secondary alignment constructed of the datums in which Datum K derives from.
Their nominal values for Datum K also do not match what the model nominal values are for the 5 surfaces making up Datum K.
I have tried going through the default report and crunching numbers but they still don't add up.
The closest I can get mathematically is 0.002 mm.

Thanks,
TK

[[Mi...]]

This isn't the answer you asked for because without seeing both programs everybody is going to be guessing.

But it sounds like you're the customer? If that's the case, and you're sure you are correct (hopefully you have a second programmer to verify your program), I would be more inclined to push the supplier to measure it my way by having them use our program.

Or at the very least it's their job to correlate their program to ours.

We are both supplier and customer depending on the job, we often push other companies to use our programs because it removes variables in trying to correlate.

[[Ri...]]

Can you layout the features and get the results?
This is how I determine who is correct or not.