Probe always travel ~10mm outside of -Y clearance plane

[[Me...]]

Hi, I have a problem with the clearance plane and I wish somebody can give me a hint.

I have a clearance plane -Y 50, +Y20, +Z 10, -Z 50;. I am not using CNC end parking position.
At the end of the program, the probe is going to check some features on the -Y side (using the -Y clearance plane), but when it finished checking, the probe will stop at -Y 62.79 instead of -50. In the CAD, the probe object shows also at -Y 62.79, outside of the clearance box.

I tried to increase the -Y clearance plane to -60, then, the probe will stop at -Y -72.79.
I also tried to use +Z clearance plane, but on +Z direction, I do not have this trouble at all, the probe will stop right at +Z 10.

Can anybody give me a hint why in -Y direction, the probe is traveling an additional 12.79 mm out of the -Y clearance plane?

Thanks in advance, I am running Calypso 5.8.

[[Ow...]]

Does the last feature use tangential probing?
I haven't the time to explain or even if I can but, if it's using tangential probing, turn that off and see if it helps.

[[Me...]]

Thanks, Owen, but I didn't active the tangential probing at all. It is a space point feature.

I tried to create a new program and a created a new probe (straight down) to test the clearance issue, I found that when I click the "test drive to selected clearance plane" button, in both +X/-X, +Y/-Y direction, the probe will travel additional 50mm away from the selected clearance plane, however, on the +Z direction, the probe will stop right at the clearance plane.

Is this from the global settings for clearance box or is this the way how Contura G2 to make sure the Vast head is also cleared out of the clearance box?

[[Ri...]]

Is there a stylus that used to be on that stylus system that isn't any more?

[[Me...]]

There is no other probes on the stylus system before, I thought the same thing at the very beginning, then to test:


I create and qualified a brand new stylus system (with only one probe pointing down) then, I created a brand new program (only 3 3-point-planes for base alignment, then made a clearance box 10 mm outside of the planes). When I select "test drive to selected clearance plane", in +X/-X, +Y/-Y directions, both the actual probe and the probe's CAD object goes 50 mm away from the selected clearance plane.

[[Re...]]

Maybe the reason is the setting of the Z-Axis diameter in cmm setup

[[Me...]]

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Thank you very much, I checked my setting, mine is vast-XT gold head, with 100mm diameter. I believe this is pretty much the reason why I got additional 50mm travel on both +/-Y, +/-X direction out of the clearance planes.

1) Are there anyway I can avoid this 50mm's additional travel? [In your case, your head is diameter 80mm, are you expiring an additional travel of 40mm? Say if you set you -Y clearance plane to be -10mm, will your probe stop at -50mm? ]
2) How did you active the CAD of your head on the screen? I can only "show probe object". [I do not have the off-line simulation license, can I still show the CAD of the head]

Thank you very much! 😜

[[Re...]]

Hello,

you should leave the setting like it is for safety reason.

1. It only drive to that diameter if you have no probe in this direction or a probe which is shorter than the safety diameter.
2. It is only possible to show the probehead with simulation license.

regards

[[Ma...]]

Is this only happening at the end of the program? Is it happening throughout the program and your not noticing it as much? My line of questioning is along the lines of clearance distance is activated to before and after or after measurement either globally or just for that one feature. This would definitely give you that type of behavior.

Clearance distance should only be applied when needed.

Mark

[[Ni...]]

Sorry to resurrect an old post but has this issue been solved?
I just got this issue yesterday and it is happening exactly the same way as the original poster. Clearance planes Y+, X+ and X- work perfectly. Clearance Y- goes to the clearance plane but then travels an additional inch or two. I have looked at every setting possible and i just cannot understand why its happening.

Googling the issue led me here so I'm wondering if this issue got fixed.

[[No...]]

Well, look at Reiner Gerke's post above and the screenshot he posted. The red line shows that not only the probe tip but the whole probe head has to be moved outside of the clearance plane. Otherwise the head might collide with the part when going further around the clearance cube. So if your stylus in +Y direction is shorter than the head diameter, the head will travel an additional distance. That was the cause of the above mentioned issue.

All you can do is to try using a different clearance plane if the feature to be measured allows it (e.g. +Z instead of -Y if you measure a vertical plane in -Y). What you should NOT do is change the head diameter in the settings shown above, as this would put you at the permanent risk of head collisons.

[[Ni...]]

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But my stylus system has a long extension on the Z- which clears the head and sensor. There shouldn't be any reason to move more than the clearance plane just to go back to the same place I need it to be.
Also for this part I am trying to scan a slot, so i need to come in from the Y-.
Z- would crash into the part, unless I add a clearance distance right?

I guess I can rotate the stylus 90°on A only for the Y+ probe so the head is not my Y- clearance plane. Right?

[[Ro...]]

This doesn't solve your problem, but you can eliminate clearance planes and use move points for features that are hard to navigate.

[[Ni...]]

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I mean that's one possibility but we have hundred of programs that would need to be adjusted.
I managed to fix the issue thanks to Norbert's explanation. I just rotated my head 90°. So instead of having my star probe at A0 B0,
Now its at A90 B0. Only for my Y+ probe though. The rest are still at A0 B0.

This puts my Y+ probe to the side of the head instead of directly in front of it. So now when my Star probe travels on Y-, it doesn't move an additional amount like before to clear for the head.

Just wanted to outline what I did to help future people with similar issue.

[[No...]]

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You are right from the perspective of a human being with a brain. But Calypso is a dumb piece of software (sorry 🤣 ). It doesn't "know" things. It doesn't even have any foresight of which movements the program will perform next. It just follows simple rules. The next move could go to -Z for whatever reason, then the head would crash into the part if it's too close.

See it from Zeiss' perspective: They need to make the CMM and software as safe as possible, which includes clear rules of movement.

[[Ni...]]

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Can't wait for zeiss to implement AI on future revisions haha.
But thank you for the explanation. I was able to fix the issue because of you.