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Sub Clearance


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I have a series of smaller diameters at the bottom of a bore that is roughly 4 inches deep. I want to measure each of them without retracting back to the Z+ CP. I have created sub clearance planes at the Z height for each of the diameters and assigned them to each feature. The CMM still retracts to the Z+ clearance plane after each measurement. I tried setting my clearance distance to zero and unchecked the Move to Before and after measuring box with no luck. I read that I need to check the Multi Clearance Plane box but it wont let me check it. Any ideas? Seems simple and I have used sub clearance in the past but only with space points not circles. I'm stumped.
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Yes, I tried that and it seems to work. I created my own SCP under Plan/Navigation/Sub clearance and gave them specific name. Inside the 4 inch bore depth I have 4 different diameters to measure. I would like to go from one to the next without retracting until the last diameter on the bottom is measured. Can I not set a SCP for each of the circles? Maybe I will try setting the default SCP +Z to just above the last feature and set all of the previous Clearance groups to SCP +Z.
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Set the same SCP for all 4 circles. Sub-clearance planes depend on the clearance plane of the next feature to work. In other words, when circle1 is done, it looks at the next feature. If the next feature uses the same sub-clearance plane, then it ignores the move to CP+Z and moves directly to the clearance distance of the next feature. If you use 0.000 for your clearance distance, then it will move from the retract distance of current feature to the retract distance of the next feature. When circle4 is finished, and it sees the next feature is not using the same sub-clearance plane, then circle4 will move the CP+Z
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Thanks Tom. I had a eureka moment while typing my last post and tried what you are suggesting. I set my SCP +Z to the Z height of the bottom circle and it worked perfect. Sometimes it helps just to talk it out with other just to get your wheels turning.
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If it is moving to clearance distance or retract distance then what is the use of inner retract distance??. I think it will move to the sub clearance plane.
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Inner plane allows you retract to 1 specific level, similar to regular clearance plane. Let's say Circle1 was at Z-1", Circle2 was a Z-2" and so on. Do I want the probe to come back to 1 level or move the shortest distance between circles?

https://youtu.be/KjnvDq7GbpE
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You're welcome

Below is a video with 10mm clearance distance.

https://youtu.be/zRxRTc0pR7Y

Look at this way. There are 7 moves associated with every feature:
1 - Clearance Plane
2 - Clearance Distance
3 - Retract Distance
4 - Probing/Scanning
5 - Retract Distance
6 - Clearance Distance
7 - Clearance Plane

When you use a sub-clearance plane with clearance distances, it moves from step 6 of current feature to step 2 of the next feature.

If your clearance distance is 0, then it moves from step 5 of current feature to step 3 on the next feature. As long as the next feature is using the same sub clearance plane.
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The first circle was at Z -.100 and the fourth was at Z -4.250. I set SCP +Z at -4.250 and assigned it to all four circles. It measured them one after the other without retracting until the last circle it retracted back to CP +Z. Clearance distance was set to 0.000 and Move to....was turned off. Perfect. Thanks!
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Interesting. I've never heard of setting the sub-clearance plane below the features. So, as long as the features are above the clearance plane, whether a normal clearance plane or a sub clearance plane set to an inner retract value, you are technically above the clearance plane.

Matthew, try turning of the inner retract value and see if it behaves exactly the same. Would save you a step in the future.
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Something to ponder.
Using Sub Clearance Planes.
All features associated to the sub clearance plane shouldn't be ran separately, they should to be ran as a group. If ran separately, make sure you are within the sub clearance plane boundary.
Features associated to sub clearance planes can crash into the part/fixture if you do not start from within the sub clearance plane boundaries.

The CMM can take off in a direction not normal to typical movements.
I rarely utilize sub clearance planes, the excess time for movements justifies the cost of a crash which can get quite expensive.
Even experienced CMM users will not realize whats happening until its to late.
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