XXT How slow do i have to go to avoid air scanning?

[[Ro...]]

XXT Articulating head.

Im having a terrible time writing programs and no matter how slow i go i get rescans and "Scanning Optimization".

Im as slow as 0.150 inch on a 1 inch diameter circle to avoid the rescans

Is there a trick i need to know? is there a setting for the Scanning Optimization?

Right now im pretty much using points on all my circles.

[[Ma...]]

You could pre scan a feature with points. I think you can do that in feature projection - not sure exact name, but a few month back it was debated here on forum.

[[Ma...]]

As Martin says you can measure, typically a 4 point circle, I name it Pre-Circle1 prior to your scanned Circle and then go to the scanned circle Projection and choose Ref Feature and select the Pre-Circle1. This will probe the 4 point circle for location then use this circle as the reference location.

[[Ri...]]

As Martin was saying, you could have it probe (4) points before measuring. Projection - Meas. Ref. - Own Geometry. 

Unfortunately this only works for Circles. 😞

As for the optimal speeds, I tend to follow the cookbook when it comes to the XXT. On a 1" diameter, the cookbook would suggest a 2mm/sec for Form, 3mm/sec for Diameter, and 5mm/sec for Position. 

There are times where you are going to get Scanning Optimization no matter what - especially as the feature size gets smaller and smaller. 

You can turn it off in Resources - Compatibility Settings, but please note that it is for the entire measurement plan, not just one feature, so use at your own caution. 

[[Za...]]

aside from what everyone else here mentioned, i'd like to share this Knowledge Base Article on the topic, which discusses a few solutions, depending on what works for you.

https://portal.zeiss.com/knowledge-base?id=443336

[[Ri...]]

I have found that most of my air scanning warnings are due to location of a feature.

It could be from incorrect nominals, or it was machined off nominal, typically this happens when a feature location is as little as .007" from nominal.

[[Ka...]]

Dear Mr. Stehlin,

How to access this knowledge base?
If I try to follow your link, i get a "page not found" message. Or is this knowledge base only accessible for US?

Regards
Karsten

 

[[Ma...]]

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[[Dr...]]

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I'd be very curious to know what the ZEISS™ Official™ positioning error threshold is for the "expected measuring force" message to appear, as well as the threshold for scanning optimization. I know it's more complicated than just positioning error, but that's the primary factor.

You've seen .007" in your experience, I have notes that say 0.1mm/.004", and the value I've parroted (though I can't remember where I first heard it) is .006", which agrees with my experience. I imagine it should be relatively consistent, and the decision of whether to perform pre-positioning can have a significant impact on cycle time.

[[Ri...]]

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The .007" came from collecting data of off a nominal feature as machined, it is an average of deviations of 50 samples. The samples were from a Ø.125 hole at a compound angle, difficult to set a center drill let alone drill the location to 1.10" depth (Thru). It made a good target as its location varied from nominal on average.

It wasn't a full-blown investigation, I just wanted to know when scanning optimization most likely occurs.

[[Za...]]

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Here is a pdf version for you Karsten.

CALYPSO_ Air Scanning & Optimization for Passive Sensor - Carl Zeiss Industrial Quality Solutions, LLC.pdf