Ideal probe angle

[[Ja...]]

Had a quick question regarding probe angle theory. What is the most appropriate choice of angle per given feature? For example, is it always better to approach "straight on" (feature has normal vector i=1, j=0, k=0 - should I rotate to A0B-90)?

If a plane has a vector somewhere in Z and X (closer to Z) is probing at A0B0 sufficient or should I rotate to be perpendicular to the plane?

Which angle in the following picture is a better choice of probe angle? If either is better, is the gain in accuracy worth the addition of time to the routine?

[[Cl...]]

My contribution.

Generally speaking, yes!

[[Ma...]]

I don't believe in the example you gave it would make a difference. It is the vector angle that is the most important, for probe compensation. Obviously it will matter when measuring an angled hole, etc.

One thing to take in consideration is the lifespan of your probe head. It is easier on the probe head to probe, in your example, in the first diagram than to always drive the probe like the second diagram.

Mark

[[Br...]]

I agree with Mark. Also another thing to consider is the fact that when the stylus is making contact at the normal vector, chatter becomes more prominent. The chatter can be filtered out but you will only increase your accuracy by reducing the chatter. This is probably more pronounced with the passive sensors than the active ones.

[[Ch...]]

I was taught that to maximize accuracy, then the example on the left is the better evaluation. The reason for this was to better utilize the tensor analysis of the bending of the stylus. Additionally, you maximize your accuracy if you approach your part from one of the machine axis'; as opposed to approaching the part at a 45 degree angle.

I can't say I've tested this and have supporting data. I'm just repeating stuff that I've heard.

[[Da...]]

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I've seen some thread/document by someone on the other forum saying the same. I also never tested if true. I have no idea what's the name of the topic, sorry.

[[Ja...]]

Great responses, thanks everyone.

[[Cl...]]

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I stand corrected.

[[Ch...]]

I remember talking to my trainer in Brighton about this. I think this is relevant information. The specific example I was talking about was when scanning a cylindrical shaft with a tight tolerance on the rotary table using the rotary table to spin the part while measuring. When doing this I always scan it with my probe orientated like the illustration on the left.

However, for most features, I probe it the way it is illustrated on the right.

[[Ri...]]

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Ditto on the RT tip. On that one I've also seen a difference when scanning a plane from the bottom on which direction I rotated (it was only a couple of microns, but it did make a difference).