ACCURACY CHECKS

[[Ry...]]

Hello Everyone,

My shop's Zeiss O-Inspect 322 was just calibrated last week and was found to have a faulty sensor causing our machine to be out of spec by a few microns. This has set off some alarm bells with upper management & they are now asking that I create a procedure to periodically verify that everything with the machine is in working order. When the calibration tech was here, I asked what we could do to validate things on our own & not have to wait for an annual calibration to find out that things are not where they should be and he told me that most shops use an artifact like a ring gage for reference.

I've ran this by our quality engineer and his response was that the unit operates at varying conditions at different distances/locations & would like to use something that would encompass the entirety of our measuring area on the Zeiss.

In the metrology shop, I found this "CMM Check 1.0 O-INSPECT, calibrated" under the references and checks section: https://shop.metrology.zeiss.com/INTERS ... ation=true

Is this what I would be looking for to satisfy our needs? What are some ways that your shop makes sure that your machine is measuring accurately?

Thanks,
Ryan

[[Cl...]]

We measure several "Master Parts" weekly. These are high volume parts. They must repeat within 10% of the tolerance of the initial master part layout.

[[DW...]]

In your case, I think it really comes down to budget. If your company is on board with paying $15,000 for an artifact then that's the right choice. The ring gage with a current calibration certificate is a decent choice for the more budget conscious folks. Periodic checks are a great idea.

[[Ry...]]

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Devin,

I think we're going to go with the ring gauge approach. Something that I am confused about is how measuring a diameter would determine that all XYZ coordinates are functioning properly. Would I make the diameter my XY origin & then take singular points in the X+, X-, Y+ & Y- directions, outputting a distance? I assume we should be using a gage block to validate the Z axis as well.

[[DW...]]

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Hopefully someone more intelligent on this topic weighs in, but I don't believe the idea behind periodic checks is to capture the entire volume of your measuring envelope. It is more or less just to verify that the machine is outputting the values you expect. By measuring the ring (which is a known diameter) and comparing it against the machine values you are verifying that the machine is still giving you the results you expect. If you do not get correlation, then it would be time to investigate.

If you would like something that better captures more of your measuring volume, perhaps a ball bar would make sense. You could then move your ball bar around the CMM volume and measure the diameters and distance between the spheres to check a larger portion of your measuring volume.

[[Ma...]]

I'm going to get this made for weekly checking probes - if will probe be out of tolerance - then requalify.
It's first prototype for just position - for wear i would still use cal. sphere.