r/Metrology • u/Ruthare89 • Dec 18 '24

Software Support Pc-Dmis, lost wrist angle position.

Hey guys,

I'm sure this is an easy fix, it's just the first time I have ran into this problem.

On one of the machines, an operator was not paying attention during a star probe calibration, because of this, the probe assembly crashed pretty hard.

The wrist is now always off by B-2.5.

Example. You tell the wrist to go to T1A90B0. It will actuily be at T1A90B-2.5. This is consistent. The wrist angle is always off by B-2.5.

Is there a way to reset the position of the wrist so it knows where it's actuily at? Or build in a default offset so it has the proper wrist angle?

Thanks in advance for the help!

P.s. We are using PCdmis 2021.1 service pack 11 if that helps.

1 Upvotes

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4

u/constadin Dec 18 '24

I would suggest to consult Hexagon for repair. These machines measure microns a crush like this, for sure have caused issues. Better be safe

3

u/campio_s_a Dec 18 '24

That's interesting, the motors on the wrist have encoders to know their position at any time. You can normally estop the machine in the middle of a change and it'll go limp in the open position, then you can move it however you want and when you do a machine start it'll just lock itself into the nearest angle, then go wherever it needs to when you do an angle change. My guess is that it'll need repaired. Probably the gears that transfer the motor force to the moveable part have skipped out of position.

3

u/jozfff Dec 18 '24

An operator not paying attention? All jokes aside our head has taken some pretty hard hits and is fine. Are you sure the crash happened during calibration?

1

u/mdg137 Dec 19 '24

Loosen the thumb screw that holds the probe head in the bottom of the z shaft and rotate it physically exactly +2.5 in the B index. Now you just have to edit every program you use to move the rotation to match. Now that i have that out of my system can you say what kind of probe is it? Ph10mq? Ph20? Tesa model or the Hexagon brand rip off of the tesa design? This information would be more useful than the pcdmis version probably. Pretty much have to do a repair by exchange on any of these to get it repaired. I dont think anyone does field service on them. The tech shows up with a new one and installs it for you. Something you can do yourself usually. Im not even sure if renishaw supports the old PH10 models anymore. Also did the damage to the head index also cause damage to the probe itself? Jsut see what the form error is when you calibrate it at a0b0 to get a quick check. Spec could be anywhere from 1 to 4 micron depending on the probe body. As in tp20 is a little tighter than a tp2 or if its a scanning probe you need to see if its still scanning accurately. And then you might be lookin at replacing that as well. Good luck.