Point ration to a scan

[[Ra...]]

We recently started measuring profiles of scans with a tighter tolerance. I was using certain features for the alignment and we noticed that it's not measuring a lot of the points for the angle of the scan. I have attached a picture and I was wondering if someone can tell me why we are not getting points all along the scan. Is there a way to get it to take more of the scan?
Do we have the speed set too high? There are no filters applied to the scan to eliminate outliers.

Global Puck Alignment.JPG

[[Th...]]

My assumption is that this is in inches? Your scan speed looks like it's way too high. That's like a tenth of an inch arc being scanned at a quarter inch per second.

[[Ch...]]

Is this on a rotary table or no?

[[De...]]

With the strategy open, right click and make sure 'Show Masked Points' is checked.

Then it should also show you any points that are measured but thrown out in red.

If it is throwing out most of the points it is likely due to scanning speed.

I would be scanning using 500 points and a speed of 0.026704 for a cylinder of that diameter.

[[Ja...]]

Derek,

How did you determine those #'s?

[[De...]]

I use half the speed Calypso recommends by default.

Otherwise it seems like I always get problems when dealing with very tight tolerances and form - and sometimes no points at all on small features.

For number of points, I figure you need a minimum of 7 points per upr for filtering and usually I am using 50 upr - so that requires a minimum of 350 - I figure the extra 150 points gives the ability to lose a lot to the outliers and still likely have enough.

It is likely overboard for a lot of stuff, but it usually gives good results.

I am sure there will be 12 people jumping up to take swipes at me citing the cookbook - but I have been using this since before there was a cookbook and I have just stuck with what works for me.

[[Ri...]]

Back in my day.... Lol.

I think the cookbook is great for beginners, but I don't like it being used as a crutch.