Stylus system rigidity

[[Do...]]

I've built a new stylus system and am curious about the rigidity values I am seeing. Based on what I've read, an ideal system would have a rigidity of 50+ while Zeiss recommends a rigidity of at least 30 to minimize deflection error. The system I've built shows a rigidity between 14 and 15 for either stylus while performing a standard Tensor qualification. I also tried a dynamic tensor qual and it was the same result. For reference, the only stylus on our machine that reaches 50+ is the masterprobe (barely). All other stylus' on our machine fall short of the 30 threshold. Both the styli and extensions are carbon fiber for this system. Is this an expected rigidity or do we have a potential issue with our Vast XT?

[[Ch...]]

try CFX Reach extensions ??

[[Wo...]]

I don't think rigidity over 50 is reachable with T extensions. I have only a few probes over 50 and they short probes directly attached to the cube or with a very short extension. Myself, I don't worry about rigidity causing issues if it is over 20.

[[Ri...]]

If you are looking for maximum rigidity, use a buildup like this as your base. 

https://shop.metrology.zeiss.com/INTERSHOP/web/WFS/IMT-US-Site/en_US/-/USD/ViewProduct-Start?SKU=626107-2040-110&CategoryName=326023&CategoryDomainName=IMT-US-300000

5mm_T.SystemDocumentation.pdf

Here's a complete buildup.

Edited yesterday at 06:01 PM

[[Ja...]]

I've always gone by the Modulus of Elasticity. I didn't know SSC would give me rigidity values. Where can I find them?

[[Do...]]

Thanks all who replied. The values seemed quite low considering the arrangement so I was inclined to believe there may be an issue with the head as none of our other systems even meet the 30 mark. Would be great if someone were able to replicate this build and obtain rigidity values on their machine to compare results.

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  Thanks Chris, I am using the Reach CFX extensions in this setup at all three joints. All components are new as well, including the adapter plate. I used the standard probing force/speed during qualification. Should those be adjusted in this case?

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 Thanks for this reference Richard. I do not have the larger extension you listed for the Z axis, but I would be curious how the results would compare. I'll look more into this if I can.

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 I was referring to the rigidity values taken from the stylus system management tab on the CMM. I do not believe SSC gives a rigidity estimation.

[[Ch...]]

nope,  for Dk = 5, 200 mN should be fine.