Find hole center

[Joe Zastrow]

Auto Features – Circle v 3.7

Where is the setting to set the depth of sample hits taken in the hole to find center?

Thanks much

[Mike N.]

if i understand correctly i think its the "check distance" under parameters F10

[tking]

In the "hits" area DEPTH, this is relative to your coordinate system origin.

Example: If the hole center at the surface is o, o, o (xyplane) DEPTH at 3 with a +1 Z feature vector would probe (center of probe) at 3 below the surface.

TK

This is for probing the feature, not sample points , duh!

[Matthew D. Hoedeman]

Not sure that is the point. Sure, you can set the depth and if you are using sample hits, it will probe that far below the surface, if you are not using sample hits, it will probe tha far below nominal. What he want is the FIND HOLE, where it goes into the hole (holefully) and starts looking for it, and it does this BEFORE it take the surface sample hits. So, if the surface of the part is 2mm low and you have a 2mm probe and a thickness of 0.5mm, using a 0.25mm depth, it will never find the hole because the actual is too low for the probe to touch. So, where is the setting for the 'search' depth is what I think he is asking, and I have no idea where it is. I had a customer program come in here once that used that functionality, and I thought it bit the big one. It spent about 5 minutes tring to find a hole and didn't so I change the all the READ POS. It meant that I had to position the probe, but that was a LOT quicker than waiting for it to find that little-bitty hole.

So, I can't give you an answer, but I hope I clarified your requestion.

[Cumofo]

Hmmm, I use find hole like mad. Even to drive aligment routines. I like it a lot cause I'm really lazy, and I like to post on obscure forums instead of werking....

Check/Distance= "The amount past the feature to check"/ "a fraction of that distance to use for the find hole feature".

[Dannyrl]

I use this quite a bit and this is something that could be addressed by Wilcox. I haven't found a way to set the depth on FIND HOLE other than using the depth that measures. As Matt said If you have a depth of .5 mm and depth is more than .5 low, the probe misses the material.
Danny

[Joe Zastrow]

Not sure that is the point. Sure, you can set the depth and if you are using sample hits, it will probe that far below the surface, if you are not using sample hits, it will probe tha far below nominal. What he want is the FIND HOLE, where it goes into the hole (holefully) and starts looking for it, and it does this BEFORE it take the surface sample hits. So, if the surface of the part is 2mm low and you have a 2mm probe and a thickness of 0.5mm, using a 0.25mm depth, it will never find the hole because the actual is too low for the probe to touch. So, where is the setting for the 'search' depth is what I think he is asking, and I have no idea where it is. I had a customer program come in here once that used that functionality, and I thought it bit the big one. It spent about 5 minutes tring to find a hole and didn't so I change the all the READ POS. It meant that I had to position the probe, but that was a LOT quicker than waiting for it to find that little-bitty hole.

So, I can't give you an answer, but I hope I clarified your requestion.

Thanks for clarifying this worthless feature Matt.

I do still need a solution for this problem, normally I measure tooled parts where there is little difference from part to part but today I am measuring fabricated parts and the hole is three bends away from the datum’s and is floating around and never in the same position.

Thanks again

[Cumofo]

GRRR!

1) Set a surface point somewhere near the feature.
2) Extract the Z value as a variable.
3) Pass that into your auto circle with find hole.
4) Log on to myspace and look for a date tonight.

[tking]

Not sure that is the point. Sure, you can set the depth and if you are using sample hits, it will probe that far below the surface, if you are not using sample hits, it will probe tha far below nominal. What he want is the FIND HOLE, where it goes into the hole (holefully) and starts looking for it, and it does this BEFORE it take the surface sample hits. So, if the surface of the part is 2mm low and you have a 2mm probe and a thickness of 0.5mm, using a 0.25mm depth, it will never find the hole because the actual is too low for the probe to touch. So, where is the setting for the 'search' depth is what I think he is asking, and I have no idea where it is. I had a customer program come in here once that used that functionality, and I thought it bit the big one. It spent about 5 minutes tring to find a hole and didn't so I change the all the READ POS. It meant that I had to position the probe, but that was a LOT quicker than waiting for it to find that little-bitty hole.

So, I can't give you an answer, but I hope I clarified your requestion.

The "duh" was for me for not reading and understanding the question before I answered. I think you've got his question nailed and I think a local Z hit is the fix (or X or Y, whatever) and depth from there.

TK

[#2#]

So, if I understand correctly the surface in which the hole is located may not be in the correct location relative to your orgin. If that is the case, can you measure the surface location changing prehit/retract in f10. Then align on the surface and measure your findhole at the depth you want.

Now another problem I have run into is when the hole isn't deep enough for the find hole function. If this is the case I fiddle with the nominals of the hole so that it stops "looking" for the hole just above the bottom of the hole. Then I just set the depth so it measures in the hole.

[Tested]

I think CUMOFO had it.

Check/Distance= *******

[Matthew D. Hoedeman]

If you use READ POS, you simply have to put the probe over the rough center of the hole and hit the DONE button on the joy-box. It will then try to measure the hole based on the location of the probe when you hit the DONE button. Sure, it take the operator to do this, but it works, and it works about 99% of the time (depending on the size of the hole). HOWEVER, you may or may not get an error when using this option in V3.7 MR3. If it is the first feature after a tip change, you will get some M error, something about a manual move in DCC or a DCC move in manual mode, something like that. Anyway, you just click on CONTINUE and it keeps going, ignoring the error which is an error in itself.

[baylorbear]

Read Position

I started out using find hole but found like someone else said Read Position was faster. We do Instument panels and consoles at my plant. When I found the Read position it save me allot of time. I use a 2mm tip and sometimes we have holes that are 3mm and sometimes a little smaller. I am sure we have all evolved in our cmm jobs and found things that changed our world like that. That is why I really like this forum because you get allot of different ideas that will make your job easier. I hope this makes sense.

[Joe Zastrow]

Thanks for the help guys

Can someone school me on what type of features you are using this on I might be using this feature incorrectly I am assuming that the find hole center is performing a mini alignment to find the hole location in 2 axis so the correct vectors are being used when measuring the hole, the 3rd axis is found with the surface sample hits that are standard to Auto Circle without find center on.

I have used the re-measure feature but decided to try find center because I have never used it and wanted to learn how it worked and thought it would be a better method of measurement.

[Matthew D. Hoedeman]

Well, I think (mind you, it is my opinion) that the FIND HOLE feature is nothing more than an animated version of READ POSITION. If you start too far off center in measuring a hole, your results COULD be skewed a little. Also, if the hole can wander away from nominal by a significant amount, it might crahs when trying to measure it. So, you tell it to find the hole. In the one program that this function was active (program from a customer) it was being used on a very small hole (for me, anyway, 3mm) that hadn't been 'locked down' to a repeatable position in the dies yet. So, it would probe 'into' the hole and if it hit on this probing, it would start moving in a spiral around the nominal locaiton, probing to find a 'no hit'. When it found a 'no-hit', it assumed that was where the hole was at. However, with the size of the hole and the size of the probe (3mm vs. 2mm) it was pretty much a lucky break if it found a 'no-hit'. However, the use of the read pos let ME put the probe in the center of the hole. In both cases, the 'no-hit' and the manual positioning, it used the location as a target location for the measurement of the hole. As far as I am concerned, if either of these options is being used, then the REMEAS option should be as well. The REMEAS option will re-measure the hole at the actual location that it just measured the hole at. This will give you the best results for the locaiton of the hole. Also, when using the READ POS and REMEAS together (as long as you respond to Pcdmis's prompts correctly) it will store the final, actual location as the target for the next measurement. Then, if the hole is off location (otherwise, why FIND or READ POS the hole?), the next time it goes to that hole (on the next part) it will move to where it was on the previous part.