Reference sphere size recommendations?

[[Th...]]

I have a Contura 7/7/6 that shipped with a 30mm reference sphere. Lately I've come to the conclusion that the sphere is too large for our typical usage, as the largest standard stylus we have in regular rotation is 2mm, and we routinely use a 0.5mm stylus as our smallest. I even have a 0.3mm unthreaded on order, and I don't think I'll be able to get good coverage with such a large ref. sphere. We do have a semi-custom 10mm diameter, short-height cylinder stylus, but this is for a very narrow set of inspections. Given this range of stylus sizes, I think either the 15mm or 8mm sphere would be best. Is there a compelling reason to choose one over the other? A 0.3mm stylus has me leaning toward the 8mm sphere for fear that the 15mm still won't let me qualify it correctly, but is there a significant downside to picking that over the 15mm sphere?

Update: The 0.3mm stylus just arrived at my desk. It is frighteningly tiny.

[[Ma...]]

Yes, you should use a smaller diameter sphere to achieve a 180 degree measurement over the sphere. With the .3mm stylus diameter a 30mm sphere this would this impossible.

With Calypso you can keep multiple calibration spheres and just switch between them as needed. This is done under Reference Sphere Management (On your Probing system qualification page, the second icon from the left).

I've used two at the same time before on a machine with a VAST Gold head. One in the #1 position and another in the #3 position. This covers the full range of styli I needed to measure.

Within the Reference Sphere Management you can also create Virtual Reference Sphere positions.

Mark

[[Th...]]

Yeah, this is ultimately what I'll do. I can probably get away with ordering just the sphere assembly and swapping it onto our existing RSH when I need to, since this .3mm isn't going to be qualified or used very often at all.