Report Machine Position for a feature and do you measure your Reference Sphere each program?

[[Mi...]]

I have been requested to start measuring the Reference Sphere (RS) after qualifying the probes used in my programs.

This was brought up by an inspector running QUINDOS on one of our Leitz Infinity machines.

As I understand it it goes like this:

1. Define Position of RS with Master Probe.

2. Qualify Probes used on RS.

3. Measure RS with Qualified Probes. (we use points only, no scanning)

4. Verify radius and machine location match #1 of list. (with form looked at as well)

5. If numbers look good (within tenths of a micron) continue programming part features.

So not only will report show part characteristic values it will show RS Machine CYS and the sphere characteristics (radius, form and ideally Machine/CMM X,Y,Z)

[[Mi...]]

The answer to your title question is no. That entire line of questioning sounds like it's coming from a manager that doesn't understand the machines and just wants it to be the same as something else. This just sounds like a can of worms.

It's not practical as in general the RS would be moved after calibration so it's position is irrelevant - Unless you have a very larg CMM, but then the argument could be that your best practice is to calibrate near where you measure so the RS would still move. We do use the RS and a really simple program as a quick and dirty "Does this CMM need calibration?" test but nothing like what you said.

I'm not sure all of that can be accomplished without PCM

But, if your sphere doesn't move.

In your program, create a Secondary Alignment, set it to "CMM System". You can then use this alignment to report features to the CMM coordinate system.

The program would have to be:

Define reference sphere position as normal ( Manual process)
Calibrate probes as normal using the Calibration Characteristic
Measure RS using whatever method and whichever probes you are required, with those features on the CMM system alignment.
Report values for those features, appropriate tolerances to satisfy your #4 point.
Condition on those characteristics to stop the program if not good.
If good, run program as normal.

One of many issues I see with this, is unless you have PCM and are quite good with it, how are you going to react to the S Value of the Calibration not being within whatever spec? That's why Calibration is generally(for us anyway) done in a separate program, immediately prior to running the sensitive one if it's required.
Why do they care where the RS is? Do they just need to be taught how Calibration works in Calypso?

[[Mi...]]

Thank you, I had seen the CMM System drop down in alignments yet it didn't click in my mind what it was for or when to use.


I was told the probing of the RS is for Verification of a Qualified Probe. Without using ring gauge or certified artifact we are more or less just trusting the CMM/software.

I measured the RS using your method using a qualified probe.
Deviation from the SR Master Probe is: +0.0017, +0.0002, -0.0005 & Dia -0.0006, form 0.0007 (50 pnts)
Granted different measuring method and points.


I'm guessing someone wrote an NCR for a part and was challenged by the machinist or programmer of how do we know our Qualified Probe is verified?

Personally I think QUINDOS programmer/operators think a little bit different.

[[DW...]]

Absolutely not.

[[Ch...]]

I would say this would add inefficiencies to each program and slow the measurement process down without adding much value. Unless there is a lot of concern for damaging probes in-between every part run.
Instead I would suggest creating a stand alone "Probe Verification Program" that you can run intermittently (however often you deem necessary for applications). This way you run a one time verification across all probes (or break it into small batches) on a regular basis but you are not slowing down each and every one of your programs.

Here is a ZEISS KBA that talks about this in a bit more detail: https://portal.zeiss.com/knowledge-base?id=2437337