Probe force issue? Probes being eaten...

[[Si...]]

See Picture.

So I notice this mainly on one supplier Part we have recently started to check due to some issues.

When I check the core to TP, eventually the center section of the Sphere becomes scratched up, gouged and also some material built up on it. I normally use a Silicon Nitride Tip, but switched to the Ruby to see if it would have the same effect, which it did.
Could this be happening due to a force applied from the CMM? I do not touch those parameters or when I calibrate as well.

Just had a second part from same supplier cause the same issue on a 1.5MM Tip today.

Anyone see this issue as well? Any tweaks I should make to mitigate it? I use the cook book for most of the measurements so not sure if maybe speed could be a factor in the scanning.

Probe Worn.JPG

[[Si...]]

Just wanted to clarify *Bore, and it is happening on a machined surface. Sometimes that surface is a little rough though.

[[Mi...]]

What is the material? I have seen that on aluminum and have had the same thing using SiN stylus on a proprietary "magnesium" alloy. Ended up using touch points. You could try a more aggressive cleaning, may be just surface oxides but that is a stretch

[[Si...]]

Aluminum Alloy, ADC12 (ALSi9Cu3) with a Finish of Trivalent Clear Chromate, MIL-C-5541 III.

[[Ri...]]

This is a problem when scanning Aluminum parts. You can try and clean with a dilute mixture of Muriatic Acid and a soft cloth but how much time and effort will it take before it would just be cheaper and easier to replace the stylus. Silica Nitride and Tungsten Carbide Stylus show slightly better performance. They still will pick up material at the equator but you might get a little more time with them before you should replace. Diamond stylus don't pick up material, I have been told. And I wasn't told that by a diamond stylus salesman.

[[Si...]]

Ok, this is great to know. Typically have Plated material but these parts are not, just strictly machined and checked on arrival.
Should I invest in at least 1 or 2 Diamond tips? But any who, thanks a lot guys for the information.

[[To...]]

Please sign in to view this quote.

Invest is a good word.

[[Si...]]

Oh I should've asked, if the piece was Plated, there would be no material build up correct? Is because these parts are not Chromated that I am seeing this.

[[Ri...]]

I am not sure about the answer to that question, Silvio. A good tool to have available is a microscope. Set up a brand new stylus and measure a ring gage, then measure 10 plated parts. Take a look at the stylus with the microscope. Is there a noticeable buildup of material at the equator? If there is, measure the ring gage again. How does the first ring gage measurement compare to the second? Testing takes time and it can be difficult to fit in with production schedules but it is a vital task that needs to be done for questions like these.