clearance distance

[[An...]]

When I go to measure a diameter, most of the time it just plunges into the hole like it is not going to the clearance distance, but sometimes it will stop above the hole at the clearance distance and then proceed into the hole. Doesn't matter if its from the CAD model or learn programming. Inside the feature strategy, the clearance distance is in there and "before and after" is checked. If another clearance distance is added in strategy, it will actually go to that clearance distance before plunging into the hole, but It will not let me delete the original clearance distance and it will go to the clearance plane twice. Has anybody experienced this?

[[Ow...]]

Clearance distance in normally set to ZERO.
The retract distance is the amount the probe stays off the bore while traveling to it.
See below.

[[An...]]

so is that basically stating that the clearance distance is only read on non-orthogonal holes? For example, lets say I have a hole that is directly on top of the part and the probe is coming straight down in z minus. I have my clearance distance set at (lets say) 5mm and then I want to measure 10mm deep inside the hole. It will dive straight down from the clearance plane to the 10mm deep inside the hole and measure the feature. I would like it to stop at the 5mm above the part first (clearance distance), then go inside the hole 10mm deep to measure. Do I understand correctly that If this were and angled hole, It would stop 5mm above the part, but if its not an angled hole, it won't?

[[Me...]]

I believe in your example you would set the clearance distance to 15mm regardless straight or angled as it is incremental from where the hole dia. is measured. You can also set the speed to enter/exit slowly through - Measurement plan editor features - travel - speed.

[[Da...]]

I'm interested if both of these 2 situations would to set clearance distance to 0? Is there any difference?

[[Ro...]]

Extras>Settings>Measurement
First tab is travel, set clearance distance default to 0 and never have to worry about odd ball movements breaking your probes anymore.

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[[SH...]]

I think,this might be due to the speed you set,while running the programming .if you wanted to feel the clearance distance, the features speed must be less than the running speed.

[[To...]]

As mentioned previously, there are 7 steps of navigation for every feature when using standard clearance planes. It is important to totally understand how these moves work, especially when troubleshooting a problem with your program,

1 - Clearance Plane
2 - Clearance Distance
3 - Retract Distance
4 - Probing/Scanning
5 - Retract Distance
6 - Clearance Distance
7 - Clearance Plane


The following assumes you're using a clearance distance like 10mm, not 0.000 and using standard clearance planes designated with "CP"

If you measure a linear feature, i.e. point, line or plane and the probe is normal to the clearance plane, i.e. plane on top of part and CP +Z, Calypso does not stop at the clearance distance. It will drop from the clearance plane right to the retract distance. If the probe is not normal to the clearance plane, i.e. plane on side and CP +Z, the probe will move to the clearance distance first, then to the retract distance.

If you measure a circular feature, i.e. circle, cylinder, cone, etc., and the probe is normal to the clearance plane, i.e. circle on top of part and CP +Z, Calypso does not stop at the clearance distance. It will drop from the clearance plane right down to the Z value of the circle, staying one retract distance away from circle radius. If the probe is not normal to the clearance plane, i.e. circle on +X side and CP +Z, the probe will move to the clearance distance first, then to the X value of the circle,circle's center, staying one retract distance away from circle radius.

Standard Sub-Clearance Planes are known as "null" sub-clearance planes. They don't move to a specific location or height. They only affect the behavior of the 7 steps listed above.

Assume you're measuring 3 circles on the top of the part. The Z value is -5mm deep. The Retract Distance is 5mm and the Clearance Distance is 10mm. For this example, let's assume the +Z Clearance Plane is 20mm above the Z origin plane.

Circle1 uses SCP +Z
Circle2 uses SCP +Z
Circle3 uses SCP 2+Z

Circle1 will start at the +Z clearance plane and unlike what I said earlier, when using sub-clearance planes, it WILL stop (hesitate) at the clearance distance, in this case, it will stop 10mm above the circle ( 5mm above the part). Next, it will drop down to the circle's height of Z-5mm and will be 5mm away from the wall of the circle. Next, it will measure the circle and retract 5mm away when it's done. Next, it will jump up 10mm to the clearance distance and compare its' SCP value to the next feature. Since Circle2 is also using SCP +Z, it will move the clearance distance of Circle2, skipping the move to the clearance plane (step 7). Circle2 will finish and look at the clearance plane of the next feature. Since Circle3 is using SCP 2+Z, which is NOT the same, the probe will move to the parent clearance plane of CP +Z.

If you are using a 0.000 clearance distance, it will jump from retract distance to retract distance, which would be disastrous in the previous example.

Sub-clearance planes need a minimum of 2 features in a row with the same sub-clearance planes in order to work. A sub-clearance plane on 1 feature will do nothing.

In an earlier post, the discussion creating new sub-clearance planes was mentioned. During this process, you have the option of ticking a "retract plane" check box. This allows you to enter a value where you want the probe to retract to in-between features, thus ignoring the clearance distance.

FYI, I've seen many drawings that show the clearance distance and clearance plane values drawn to the center of the probe. What I have found is the value is to the tip of the probe. In other words, a 10mm clearance plane or clearance distance will allowing a 10mm pin or block to slide snugly under the probe.

[[Me...]]

Great explanation, Tom! ❗

[[Ri...]]

The majority of the work I do doesn't need a clearance distance - retract can handle my needs.

Clearance distance is a must when measuring holes that aren't perpendicular to a surface.

There are other cases where I was trying to get into a deep bore that I needed to come from the +Y, but I was unable to use that clearance plane, so setting it to use the +Z and utilizing the clearance distance helped getting in and out of the feature.

I do get driven mad by watching programs run and people just use a blanket cd & rd, and the probe is close to smacking into walls getting in and out of the feature.

[[To...]]

If you want to see the clearance distance and retract distance positions, go to CAD > Settings > Strategy and tick Clearance Positions checkbox. When you open a feature, you will now see 2 arrows. The clearance distance and retract distance will be represented at each end of the arrows. These 2 locations will be probe center representations. The arrows will not appear if you use a 0.000 clearance distance. These arrows are helpful in determining navigation into an angled hole like Richard was talking about.

[[Cl...]]

Is that a global setting?

[[To...]]

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Yes. In the same CAD Settings window, click on Save and Load and click Save as System Setting

[[Te...]]

The Clearance Distance box tends to "uncheck" itself for some reason, been these way forever. If you don't see the brown and purple arrows just turn it back on and close out the feature and re-open and they will show back up.