Probe Calibration issues

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armymachinist
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Probe Calibration issues

Post by armymachinist » Mon Sep 14, 2020 5:05 pm

I am having issues with probe calibration. Running CMM Manager 3.9 SP2, on a Brown and Sharpe CMM with a PH10MQ head and an SP25M probe with SM25-1 module. Ref_Tip is 4mm X 25mm.

A few days ago I wrote a program, and attempted to calibrate the probe before running it. When the machine moved the probe above the calibration sphere, it beeped, like it had made contact, even though the probe tip was still out in space.
My first step to fix this was to calibrate my Ref_Tip. That resulted in the same behavior, the machine would beep like it had taken a hit, but the tip had not touched anything. At this point I restarted my computer and the machine. After homing the machine I attempted to calibrate the Ref_Tip again. I had the same results This time I moved the tip closer to the sphere, much closer than the software designated half inch. The calibration cycle started to work normally. It took four points around the hemisphere and then went to begin the scanning cycles. When it started to scan, the indicator lights on the probe head went out as normal, but again, the probe tip was not contacting the calibration sphere. The tip was approx. ¼” away from the sphere, moving like normal. Out of frustration I attempted calibration twice more before it finally was acting normal. I did not change anything, I just kept trying until it worked.

Once the Ref_Tip was successfully calibrated, I measured a ring gage and the results were dead on. I then attempted to calibrate a different probe to verify my results, and the odd machine behavior started all over, again taking several attempts to get any of my probes to calibrate. But still, each probe measured my ring gage with good results once it had been calibrated.

Has anyone ran into issues like this? I need to get this issue resolved ASAP. I have also tried using the "Locate Cal. Sphere" function, without any luck.

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Re: Probe Calibration issues

Post by armymachinist » Tue Sep 15, 2020 4:13 pm

Update. Today I shutdown both the machine and computer, and then unplugged both from their power source for a few minutes before restarting. This seemed to fix the problem and I was able to calibrate a few tips without issue. Unfortunately the issue soon returned and I am back where I started.

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Re: Probe Calibration issues

Post by CMM Guru » Wed Sep 16, 2020 6:35 am

What controller do you have? UCC? Do you have another SP25 body/module you can substitute and try? This is sounding a bit like there has been a crash and the -1 may be... "off center" which would require an RBE from Renishaw. The only easy way to test this is to try another module though.

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Re: Probe Calibration issues

Post by armymachinist » Wed Sep 16, 2020 8:38 am

unfortunately we do not have any spare modules. We do not have UCC. Controller wise I believe it is an LK controller. What is an "RBE" from Renishaw?

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Re: Probe Calibration issues

Post by armymachinist » Wed Sep 16, 2020 4:23 pm

Another update.

After spending some time on the phone with Nikon, it appears that our SM25-1 is faulty. Possibly due to excessive probe lengths over an extended period of time. After some digging, I found a SM25-5 module that we have, but for some reason have not been using. I am going to get some probes built on this module and will hopefully see this issue resolved. I will update in the future.

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Re: Probe Calibration issues

Post by CMM Guru » Thu Sep 17, 2020 7:22 am

I was indeed suspecting a faulty -1 module.

An RBE is Repair By Exchange.

If the -5 works correctly, even if you go back to a -1, it is a pretty good indicator that the -1 is indeed bad.

Just so you are aware, SP25's are a very delicate component compared to tactile probes. A 6" drop at just the right (wrong?) angle to the granite can "offset" the internals to a point where it will no longer work. This applies to the SP25 body as well.

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Re: Probe Calibration issues

Post by armymachinist » Fri Sep 25, 2020 1:54 pm

Hopefully the final update: We ended up with a -2 module, which was recommended by Renishaw, for our application. So far everything seems to be working out. All tips have calibrated without issue.

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