Probe life input?

[[Do...]]

Good afternoon Forum!
I just recently in 7 year career of programming, running, and upkeeping, a CMM and its young brother, ran into the first time in our shop that I have to replace a probe due to wear! (continuous improvement is paying off. 😉 )

Having said that, does anyone in our vast community have any insight on how long both Ruby and Silicon Nitride are capable of being utilized before the flat on the sphere is egregious enough to have the probe fail all qualifications?
A few preface bits of info: hours would be useful over days, due to the great deal of difference between 4-6 hours of continual use we have on average, and some places who run 24/7.
100% dynamic (probe measuring force)
Ø's from .0197m - .0984M
Lengths range from 1.5" - 3.5" with extensions.

Any insight anyone can offer would be greatly appreciated! :}

[[Do...]]

Forgot something.
70% of the measuring is being done in Z axis (A0B0) another 10% is angled but still uses the surface area affected by scanning in Z+.

😃

[[To...]]

I don't have an answer to your specific question but I have some thoughts on a related topic.

Unfortunately, the probe qualification may not be a "fail safe" method to determine whether a probe has a wear issue. After the scanning portion of a Passive Qualification, the routine takes 6 points on the reference sphere. The 2 points on top are not directly at the center so you may not pick up the beginnings of a worn flat on the end. To get a better idea of the condition of a stylus, it is a common practice to create a program that scans a sphere artifact (Zeiss does not recommend using the Reference Sphere), however I think it will work in a pinch. The routine would have Base Alignment to pick up the X/Y and Z origin on the sphere using the Master Probe. Then, with your stylus, measure a sphere, scanning in various directions, i.e. around the equator and over the top in Z/X and Y/Z planes. Then, evaluate X, Y, Z and roundness of the sphere. Since the artifact is probably rounder than we can detect, any form deviation will be from the probe itself. 2 cents.

[[Ri...]]

I wouldn't rely so heavily on your sigma value to determine if you have a flat spot. I've had probes develop flat spots, but not show much over a micron of sigma.

I would suggest adding redundant checks to catch things like this.

[[Do...]]

We actually could not get our long medium probe to qualify with any form of qualification process. (auto, manual, etc.) even with dynamic change. I put in our magnified comparator to see what could be causing the issue ( I've . The sphere had a .0125" flat on the tip. (.3175mm) upon replacement everything was fine from there (qualification wise, we use the geometry requalification for our daily routine, and the passive once a month on all angles)
The biggest concern was the fact that a part showed out of tolerance on the machine with the affected probe. It's younger brother measured the part in tolerance.
If I can find an acceptable timeline that isn't too short, yet not long enough to potentially cause another incorrect "red" tag, would be ideal.

Having said that I can't recall to many times where "ideal" actually happens, but shoot for the stars right? 🤣

[[Ty...]]

I think there is too much variance to give expected hours of use. Like others have said, you can't trust the sigma value to let you know if there is ware. I've started to also look at the radius. If there is a flat spot or too much build up, the radius value should give a red flag. If you have a 2mm probe and radius is measuring 0.970, there is an issue with your probe.

[[Is...]]

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That's the reason what I miss the max/min calibration values from ZEISS Umess Software, See this topic:
viewtopic.php?f=18&t=1298

[[To...]]

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I see the flat spot difference if I use a 6 point calibration vs the dynamic (which does the same thing with the 2 top points being off from the top dead center). Dynamic tensor sigma looks good, but the 6 point sigma bad.