calibration issue ?

[francisco_cmm]

Hello all!

I just really confused my self here. I heard someone last week saying the my CMM calibration ( Global Image) calibrates in Microns.? I always though it was on the tents. I'm inspecting parts that are .0004 tents on profile, I get results of .0009 tents.
now going back to my calibration results are .0004 tents. could this tents be issue on why my profile is coming out bad? I also get the same results when I do total runout.

UPDATE: CALIBRATION WAS DONE IN INCHES THEN I RAN THIS PROGRAM ON MM

[Hi-Tech Redneck]

I always thought it calibrated in whatever unit the program was set up in...

[francisco_cmm]

I thought so too. but then I heard some one that it calibrated in microns ? so I'm confused now lol

[BIGWIG7]

so whats the question here?

[francisco_cmm]

two questions.

one does the cmm calibrate in inches ?

second could the dev on my probe calibration be the reason why my profile is coming out bad ?

[BIGWIG7]

yes It calibrates in inches.
it could be but it's highly likely.
I would recalibrate and rerun your program and see if the deviation repeats.

[acgarcia]

Yes it can calibrate in inches. Check your displayprecision to 4 or 5

[acgarcia]

Yes, if ur probe has a flat spot or build up on one side it can show bad results.

[acgarcia]

I think the lower matrix calibration must be calibrated in mm

[RIDER]

When Hexagon calibrates your machine, the reports are in microns. When you qualify your probes, the results are in the unit you chose when you created the program.
Also, if you have 0.0004" standard deviation on your results, I would not trust the data that you get on a 0.0004" profile call-out. I would clean the sphere and the ruby with alcohol and blow them off with compressed air before re-measuring the tip angle. If you're checking ±0.0002", you need to eliminate as many uncertainties as you possibly can. The software is going to always give you a number. The crux is knowing that you can trust that number.
HTH

[francisco_cmm]

I am having calibration be done to the machine in a few weeks. I also clean everything and continue to see the same results no matter how many time I change to a different probe.

[francisco_cmm]

UPDATE:
I continue to calibrate the probe ( different probes ) I check to make sure the sphere and probes are all clean. I reset tips and re-did calibration 3 times each probe different speeds and all probes Standard Deviation of .0003. all probes repeated the same. all of our prints are +/- .0001 - .0002 - .0003.. could this deviation be the reason why some profiles come out .0003 out of tolerance? because of the deviation. print calls out for probile to be .0003 and results are .0006

[Schlag]

tenths.... in this case, short for ten thousandths

[francisco_cmm]

right

[RIDER]

What are the details of your machine (probe, controller, probe build, etc.)?

[francisco_cmm]

Global B&S Image, Renishaw PH10QM SP25M TM25-20 3X50MM

[Mike Ruff]

Have you tried calibrating with more points/levels? I usually use 3 levels and 13 hits, but if my STDs start getting worse then I will increase the hits to 17, 19, or 23. It usually gets better and my STDs become more manageable

[francisco_cmm]

thanks mike, I did that and it got a bit better. instead of .0004 is now .0003.

I guess that's as good as it gets.

[Douglas]

3 levels and 13 hits is my standard as well giving 7 hits first level, 5 on second and one at the top.