Cylindrical Base alignment

[[sh...]]

Good Afternoon,


I'm new to Calypso but I've creating programs with PCDMIS in the past. Currently, Calypso seems much more user friendly and at the moment I'm attempting to create a base alignment using 1 cylinder and 1 plane with the cylinder laying in a V-Block.

When i construct this base alignment the CMM continues to try and scan in different areas of the part , it knows where the cylinder is, it just believes it should start scanning the cylinder in different areas. I've set the start and end angles of the scan correctly and watched it run afterwards. Closing and then opening the program days later it will change, Why would it do this? Would anyone have more insight into this matter?


Thanks in advance!

[[To...]]

Can you post screenshots of your base alignment, and the 2 feature windows?

[[Aa...]]

I would need to see a screenshot of your base alignment and the 2 feature windows to know for sure, But I would assume that your plane is being used for "planar rotation", even though it likely doesn't control the rotation of the part. I have seen this several times on parts where a cylinder is the primary datum, and an end plane on the part is a secondary datum, being the only 2 datum features called out.

If you extract both of these features, and look at the Space Axis that these rest on, they are the same axis (see attached example). I am unsure of exactly how calypso interprets this, however, it seems to me that when the plane is used as the "Planar Rotation" calypso tries to clock the part to the plane origin (or measured plane origin), while still "showing" an alignment that makes sense for the part. This then throws off the actual starting rotation for the program, but all the features will still appear correct (because their locations have not changed, only the rotation that calypso believes it is starting at). I have run into this issue multiple times, and every time it was for the exact same reason, I used a plane for planar rotation, that did not control the rotation from datum A.

The best solution I have found for this is to NOT use a Planar rotation (as the quick example I attached shows). I work with a company that uses many shaft parts that are dimensioned like this. If there are no shafts/bores perpendicular to the main axis of the Shaft, then the part is usually (for me) identical around 360 degrees, and therefore cannot utilize the Planar rotation, as there is no feature to control that rotation. The plane in this case is ONLY setting the Z location (based on my example).

Secondary Datum.PNGPrimary Datum.PNGIncorrect Base Alignment.PNGCorrect Base Alignment Per example.PNG

[[sh...]]

Sounds like exactly what was occurring! Luckily inside of the part close to the end, There were two small radii that were 180° from each other.I used those features to construct a line and used that line for rational purposes. "locking in/skewing,clocking". Or in Calypso speak ...Planar Rotation

Thanks !