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Haas Renishaw Probe issues

velocity101

Aluminum
Joined
Apr 21, 2013
Location
United States
Can anyone help shed some light and/or correct me if I'm making a mistake somewhere in the process.

I have a 2014 Haas VF2 with Renishaw probe. The issue I'm having is the disparity in sizes when I measure a part with calipers (quality Mitutoyo) and when I use the probe to measure the size of the same part. My process (with the probe) is probe both sides of a part and calculate the size by subtracting one number from the other. The probe seems to measure the part with a 0.35mm - 0.40mm error. I've also done this with precision parts (to eliminate caliper error) with known sizes--and the probe comes out with this size disparity as well.

I've run the probe calibration cycles as well as physically balanced the ruby stylus tip (0.05mm+/-)... Am I doing something wrong or is there something wrong with my machine/probe???
 
Are you doing this manually, or in a probing cycle like measure boss or bore? The cycle calls the probe calibration data. Doing it manually may not. I find I'm generally +/- .0005 or better with the probe using inspection plus from Renishaw.
 
Are you doing this manually, or in a probing cycle like measure boss or bore? The cycle calls the probe calibration data. Doing it manually may not. I find I'm generally +/- .0005 or better with the probe using inspection plus from Renishaw.

I'm using the built-in Haas cycles for the probe but measuring a single direction at a time; for instance > I'm measuring X+ on one side and then X- on the other side to calculate the width of a part. I'm only doing as a test because I noticed a discrepancy between what I CAD modeled and what my probe was showing; and sure enough, the probe is giving me different dimension than what the part should really be.

a +/-.0005 would be acceptable, however, I'm getting +/-0.0078" which might as well be a mile.
 
What you modeled in CAD means spit. That's what size the part should be, assuming your tools cut on center and they are the optimal diameter. A tool that runs out or is a larger diameter will make your part too small. The point of probing is to check so you can shift a tool wear offset and come to size as needed. As far off as you are, I'd stick an indicator and measure the runout of the probe. It's either not running true, or you have incorrect calibration data entered. Chck the probe for runout and adjust it to the tiniest value possible, then recalibrate your probe. Not sure about HAAS, but Renishaw has 2 ways to do so, and you want to use the longer method that picks up calibration data from several angles. MAke sure the ring you use to calibrate the probe is accurate as well.
 
Runout of your probe tip is .05mm? That's pretty crappy.

Are you leaving the probe in the machine? If not, and you have that much runout, then load the probe oriented incorrectly, you will have terrible results.

Sure it can have some runout, and the calibration does correct for this, but .05mm is a LOT. I'd say you should try to get that down to .01mm Not very hard, just be patient.

Second, what are you using to calibrate? Ring gage? And more importantly, are you verifying after the calibration? Run a bore measuring cycle. Check #188 for size.

My guess is it's not kept in the machine and being loaded backwards. Right?
 
Runout of your probe tip is .05mm? That's pretty crappy.

Are you leaving the probe in the machine? If not, and you have that much runout, then load the probe oriented incorrectly, you will have terrible results.

Sure it can have some runout, and the calibration does correct for this, but .05mm is a LOT. I'd say you should try to get that down to .01mm Not very hard, just be patient.

Second, what are you using to calibrate? Ring gage? And more importantly, are you verifying after the calibration? Run a bore measuring cycle. Check #188 for size.

My guess is it's not kept in the machine and being loaded backwards. Right?

I do actually keep the probe in the toolchanger. Your tip on the calibration ring rang a lightbulb though! During probe calibration, I was not entering the PRECISE size; I was entering 25mm when I should have measured the precise bore and entered 25.35mm -- THIS is what made all the difference and now everything matches up!

Thank you!
 
Glad you got it worked out. I agree with others about how much runout you have. I can usually indicate the probe tips to .0002" (.005mm) easily and never let it go more than .005" (.0125mm).
 
I think it's important to note that the Renishaw manual states to indicate the probe tip to ±.0025mm (essentially ±.0001", so .0002" total runout). I recently indicated ours after a slight probe crash that required replacing a part and indicated to .0001" total runout. Took about 20 minutes in total. Not too bad really.
 








 
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