Base Alignment Error Too Many Iterations

[[Co...]]

We started having a problem for one of our parts where it does the base alignment but for some reason doesnt calculate it right so it forgets where it is and starts speeding towards the fixture. It shows this error right before. Does anyone have any help with how to fix this. We have ran this part for years now all of a sudden it cannot do the base alignment correctly. What does this error mean?

error.png

[[Ma...]]

It's hard to answer your problem. But mostly common is using bad setup for base alignment - aka not reliable features.
Often people make base alignment same as DRF on drawings.

Did you upgrade Calypso?

My problem was using cylinder +Y and sphere on +X position to keep it in same height - i rather use 3d line from sphere to cylinder to have reliable alignment.

[[Cl...]]

I'd start with the Base Alignment itself. Go through it feature by feature, looking for errors.

[[Ke...]]

It looks like it does not like the Slot, specifically.
Open the feature:
How does the Form look?
If you cannot view the measured points, then right click on the screen and select view all measured points.
It may help to slow down the scanning speed, and/or increase the data collection.

[[Co...]]

Yes this only happens after it measures the slot. I used the same datums as on the print and we have been running this for a long time. I have tried increasing the number of points and slowing down the speed. We also did recently just upgrade our calypso this could have been the reason? This part is 8ft long with datums being a slot on one end and a hole on the opposite end then a basic A plane.

[[No...]]

Technically, the error means that the best fit algorithm reached its maximum limit of iterations before it could achieve a stable result. All best fit algorithms like Gauss etc. are approximations which repeatedly iterate until the remaining error is small enough and doesn't change (much) anymore on further iterations.
Practically this could mean some alignment features give unstable results, like Martin already said. But it's only one of several possibilities.

[[Ke...]]

Could you post screenshots of the features in question, including the nominals, strategies, and evaluation settings? It may be possible for someone to spot a cause in that information.

[[Co...]]

Yes here is all the information for the slots. I have the base alignment looped and the slot referenced so I thought this would give it enough stability and it was working until around the time we upgraded calypso. I am not sure what this would have to do with it but the timing matches. This is the information for the reference slot, the actual feature has all the same strategies below.

Capture1.PNG

[[Ke...]]

The only thing I see in the screenshots that stands out as a potential cause is the 5 adjacent points, perhaps try reducing that to 3 (or for testing, turn it off entirely on a part that fails to calculate and see if it resolves), especially depending on how many filtering iterations you are using. I most frequently see the Too Many Iterations error when there is not a sufficient number of points for calculation either due to too few sampled points or highly aggressive filtering, or on conical features where the scans are too close together for Calypso to calculate an angle or the physical feature is not conical.

[[Er...]]

In my experience...
Look at the points from the scan. They are probably going everywhere. A lot of them are probably red.
The deviation from where the slot is expected to be is too much.
With an XXT I cannot scan slots in a base alignment. I have to use single points or I get the same type of response from Calypso.

[[Co...]]

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Thank you, this is what we ended up doing to get it to run fine with no problems anymore.